src/stdlib/SDL_malloc.c
author Ryan C. Gordon <icculus@icculus.org>
Sat, 14 Jul 2007 06:46:33 +0000
changeset 2194 55e987d8e1b5
parent 1895 c121d94672cb
child 2196 2aee80dab68a
permissions -rw-r--r--
Merged r3255:3256 from branches/SDL-1.2: stdlib problem with SDL_memcpy macro.
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2006 Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Lesser General Public
     7     License as published by the Free Software Foundation; either
     8     version 2.1 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Lesser General Public License for more details.
    14 
    15     You should have received a copy of the GNU Lesser General Public
    16     License along with this library; if not, write to the Free Software
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 #include "SDL_config.h"
    23 
    24 /* This file contains portable memory management functions for SDL */
    25 
    26 #include "SDL_stdinc.h"
    27 
    28 #ifndef HAVE_MALLOC
    29 
    30 #define LACKS_SYS_TYPES_H
    31 #define LACKS_STDIO_H
    32 #define LACKS_STRINGS_H
    33 #define LACKS_STRING_H
    34 #define LACKS_STDLIB_H
    35 #define ABORT
    36 
    37 /*
    38   This is a version (aka dlmalloc) of malloc/free/realloc written by
    39   Doug Lea and released to the public domain, as explained at
    40   http://creativecommons.org/licenses/publicdomain.  Send questions,
    41   comments, complaints, performance data, etc to dl@cs.oswego.edu
    42 
    43 * Version 2.8.3 Thu Sep 22 11:16:15 2005  Doug Lea  (dl at gee)
    44 
    45    Note: There may be an updated version of this malloc obtainable at
    46            ftp://gee.cs.oswego.edu/pub/misc/malloc.c
    47          Check before installing!
    48 
    49 * Quickstart
    50 
    51   This library is all in one file to simplify the most common usage:
    52   ftp it, compile it (-O3), and link it into another program. All of
    53   the compile-time options default to reasonable values for use on
    54   most platforms.  You might later want to step through various
    55   compile-time and dynamic tuning options.
    56 
    57   For convenience, an include file for code using this malloc is at:
    58      ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.3.h
    59   You don't really need this .h file unless you call functions not
    60   defined in your system include files.  The .h file contains only the
    61   excerpts from this file needed for using this malloc on ANSI C/C++
    62   systems, so long as you haven't changed compile-time options about
    63   naming and tuning parameters.  If you do, then you can create your
    64   own malloc.h that does include all settings by cutting at the point
    65   indicated below. Note that you may already by default be using a C
    66   library containing a malloc that is based on some version of this
    67   malloc (for example in linux). You might still want to use the one
    68   in this file to customize settings or to avoid overheads associated
    69   with library versions.
    70 
    71 * Vital statistics:
    72 
    73   Supported pointer/size_t representation:       4 or 8 bytes
    74        size_t MUST be an unsigned type of the same width as
    75        pointers. (If you are using an ancient system that declares
    76        size_t as a signed type, or need it to be a different width
    77        than pointers, you can use a previous release of this malloc
    78        (e.g. 2.7.2) supporting these.)
    79 
    80   Alignment:                                     8 bytes (default)
    81        This suffices for nearly all current machines and C compilers.
    82        However, you can define MALLOC_ALIGNMENT to be wider than this
    83        if necessary (up to 128bytes), at the expense of using more space.
    84 
    85   Minimum overhead per allocated chunk:   4 or  8 bytes (if 4byte sizes)
    86                                           8 or 16 bytes (if 8byte sizes)
    87        Each malloced chunk has a hidden word of overhead holding size
    88        and status information, and additional cross-check word
    89        if FOOTERS is defined.
    90 
    91   Minimum allocated size: 4-byte ptrs:  16 bytes    (including overhead)
    92                           8-byte ptrs:  32 bytes    (including overhead)
    93 
    94        Even a request for zero bytes (i.e., malloc(0)) returns a
    95        pointer to something of the minimum allocatable size.
    96        The maximum overhead wastage (i.e., number of extra bytes
    97        allocated than were requested in malloc) is less than or equal
    98        to the minimum size, except for requests >= mmap_threshold that
    99        are serviced via mmap(), where the worst case wastage is about
   100        32 bytes plus the remainder from a system page (the minimal
   101        mmap unit); typically 4096 or 8192 bytes.
   102 
   103   Security: static-safe; optionally more or less
   104        The "security" of malloc refers to the ability of malicious
   105        code to accentuate the effects of errors (for example, freeing
   106        space that is not currently malloc'ed or overwriting past the
   107        ends of chunks) in code that calls malloc.  This malloc
   108        guarantees not to modify any memory locations below the base of
   109        heap, i.e., static variables, even in the presence of usage
   110        errors.  The routines additionally detect most improper frees
   111        and reallocs.  All this holds as long as the static bookkeeping
   112        for malloc itself is not corrupted by some other means.  This
   113        is only one aspect of security -- these checks do not, and
   114        cannot, detect all possible programming errors.
   115 
   116        If FOOTERS is defined nonzero, then each allocated chunk
   117        carries an additional check word to verify that it was malloced
   118        from its space.  These check words are the same within each
   119        execution of a program using malloc, but differ across
   120        executions, so externally crafted fake chunks cannot be
   121        freed. This improves security by rejecting frees/reallocs that
   122        could corrupt heap memory, in addition to the checks preventing
   123        writes to statics that are always on.  This may further improve
   124        security at the expense of time and space overhead.  (Note that
   125        FOOTERS may also be worth using with MSPACES.)
   126 
   127        By default detected errors cause the program to abort (calling
   128        "abort()"). You can override this to instead proceed past
   129        errors by defining PROCEED_ON_ERROR.  In this case, a bad free
   130        has no effect, and a malloc that encounters a bad address
   131        caused by user overwrites will ignore the bad address by
   132        dropping pointers and indices to all known memory. This may
   133        be appropriate for programs that should continue if at all
   134        possible in the face of programming errors, although they may
   135        run out of memory because dropped memory is never reclaimed.
   136 
   137        If you don't like either of these options, you can define
   138        CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything
   139        else. And if if you are sure that your program using malloc has
   140        no errors or vulnerabilities, you can define INSECURE to 1,
   141        which might (or might not) provide a small performance improvement.
   142 
   143   Thread-safety: NOT thread-safe unless USE_LOCKS defined
   144        When USE_LOCKS is defined, each public call to malloc, free,
   145        etc is surrounded with either a pthread mutex or a win32
   146        spinlock (depending on WIN32). This is not especially fast, and
   147        can be a major bottleneck.  It is designed only to provide
   148        minimal protection in concurrent environments, and to provide a
   149        basis for extensions.  If you are using malloc in a concurrent
   150        program, consider instead using ptmalloc, which is derived from
   151        a version of this malloc. (See http://www.malloc.de).
   152 
   153   System requirements: Any combination of MORECORE and/or MMAP/MUNMAP
   154        This malloc can use unix sbrk or any emulation (invoked using
   155        the CALL_MORECORE macro) and/or mmap/munmap or any emulation
   156        (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system
   157        memory.  On most unix systems, it tends to work best if both
   158        MORECORE and MMAP are enabled.  On Win32, it uses emulations
   159        based on VirtualAlloc. It also uses common C library functions
   160        like memset.
   161 
   162   Compliance: I believe it is compliant with the Single Unix Specification
   163        (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably
   164        others as well.
   165 
   166 * Overview of algorithms
   167 
   168   This is not the fastest, most space-conserving, most portable, or
   169   most tunable malloc ever written. However it is among the fastest
   170   while also being among the most space-conserving, portable and
   171   tunable.  Consistent balance across these factors results in a good
   172   general-purpose allocator for malloc-intensive programs.
   173 
   174   In most ways, this malloc is a best-fit allocator. Generally, it
   175   chooses the best-fitting existing chunk for a request, with ties
   176   broken in approximately least-recently-used order. (This strategy
   177   normally maintains low fragmentation.) However, for requests less
   178   than 256bytes, it deviates from best-fit when there is not an
   179   exactly fitting available chunk by preferring to use space adjacent
   180   to that used for the previous small request, as well as by breaking
   181   ties in approximately most-recently-used order. (These enhance
   182   locality of series of small allocations.)  And for very large requests
   183   (>= 256Kb by default), it relies on system memory mapping
   184   facilities, if supported.  (This helps avoid carrying around and
   185   possibly fragmenting memory used only for large chunks.)
   186 
   187   All operations (except malloc_stats and mallinfo) have execution
   188   times that are bounded by a constant factor of the number of bits in
   189   a size_t, not counting any clearing in calloc or copying in realloc,
   190   or actions surrounding MORECORE and MMAP that have times
   191   proportional to the number of non-contiguous regions returned by
   192   system allocation routines, which is often just 1.
   193 
   194   The implementation is not very modular and seriously overuses
   195   macros. Perhaps someday all C compilers will do as good a job
   196   inlining modular code as can now be done by brute-force expansion,
   197   but now, enough of them seem not to.
   198 
   199   Some compilers issue a lot of warnings about code that is
   200   dead/unreachable only on some platforms, and also about intentional
   201   uses of negation on unsigned types. All known cases of each can be
   202   ignored.
   203 
   204   For a longer but out of date high-level description, see
   205      http://gee.cs.oswego.edu/dl/html/malloc.html
   206 
   207 * MSPACES
   208   If MSPACES is defined, then in addition to malloc, free, etc.,
   209   this file also defines mspace_malloc, mspace_free, etc. These
   210   are versions of malloc routines that take an "mspace" argument
   211   obtained using create_mspace, to control all internal bookkeeping.
   212   If ONLY_MSPACES is defined, only these versions are compiled.
   213   So if you would like to use this allocator for only some allocations,
   214   and your system malloc for others, you can compile with
   215   ONLY_MSPACES and then do something like...
   216     static mspace mymspace = create_mspace(0,0); // for example
   217     #define mymalloc(bytes)  mspace_malloc(mymspace, bytes)
   218 
   219   (Note: If you only need one instance of an mspace, you can instead
   220   use "USE_DL_PREFIX" to relabel the global malloc.)
   221 
   222   You can similarly create thread-local allocators by storing
   223   mspaces as thread-locals. For example:
   224     static __thread mspace tlms = 0;
   225     void*  tlmalloc(size_t bytes) {
   226       if (tlms == 0) tlms = create_mspace(0, 0);
   227       return mspace_malloc(tlms, bytes);
   228     }
   229     void  tlfree(void* mem) { mspace_free(tlms, mem); }
   230 
   231   Unless FOOTERS is defined, each mspace is completely independent.
   232   You cannot allocate from one and free to another (although
   233   conformance is only weakly checked, so usage errors are not always
   234   caught). If FOOTERS is defined, then each chunk carries around a tag
   235   indicating its originating mspace, and frees are directed to their
   236   originating spaces.
   237 
   238  -------------------------  Compile-time options ---------------------------
   239 
   240 Be careful in setting #define values for numerical constants of type
   241 size_t. On some systems, literal values are not automatically extended
   242 to size_t precision unless they are explicitly casted.
   243 
   244 WIN32                    default: defined if _WIN32 defined
   245   Defining WIN32 sets up defaults for MS environment and compilers.
   246   Otherwise defaults are for unix.
   247 
   248 MALLOC_ALIGNMENT         default: (size_t)8
   249   Controls the minimum alignment for malloc'ed chunks.  It must be a
   250   power of two and at least 8, even on machines for which smaller
   251   alignments would suffice. It may be defined as larger than this
   252   though. Note however that code and data structures are optimized for
   253   the case of 8-byte alignment.
   254 
   255 MSPACES                  default: 0 (false)
   256   If true, compile in support for independent allocation spaces.
   257   This is only supported if HAVE_MMAP is true.
   258 
   259 ONLY_MSPACES             default: 0 (false)
   260   If true, only compile in mspace versions, not regular versions.
   261 
   262 USE_LOCKS                default: 0 (false)
   263   Causes each call to each public routine to be surrounded with
   264   pthread or WIN32 mutex lock/unlock. (If set true, this can be
   265   overridden on a per-mspace basis for mspace versions.)
   266 
   267 FOOTERS                  default: 0
   268   If true, provide extra checking and dispatching by placing
   269   information in the footers of allocated chunks. This adds
   270   space and time overhead.
   271 
   272 INSECURE                 default: 0
   273   If true, omit checks for usage errors and heap space overwrites.
   274 
   275 USE_DL_PREFIX            default: NOT defined
   276   Causes compiler to prefix all public routines with the string 'dl'.
   277   This can be useful when you only want to use this malloc in one part
   278   of a program, using your regular system malloc elsewhere.
   279 
   280 ABORT                    default: defined as abort()
   281   Defines how to abort on failed checks.  On most systems, a failed
   282   check cannot die with an "assert" or even print an informative
   283   message, because the underlying print routines in turn call malloc,
   284   which will fail again.  Generally, the best policy is to simply call
   285   abort(). It's not very useful to do more than this because many
   286   errors due to overwriting will show up as address faults (null, odd
   287   addresses etc) rather than malloc-triggered checks, so will also
   288   abort.  Also, most compilers know that abort() does not return, so
   289   can better optimize code conditionally calling it.
   290 
   291 PROCEED_ON_ERROR           default: defined as 0 (false)
   292   Controls whether detected bad addresses cause them to bypassed
   293   rather than aborting. If set, detected bad arguments to free and
   294   realloc are ignored. And all bookkeeping information is zeroed out
   295   upon a detected overwrite of freed heap space, thus losing the
   296   ability to ever return it from malloc again, but enabling the
   297   application to proceed. If PROCEED_ON_ERROR is defined, the
   298   static variable malloc_corruption_error_count is compiled in
   299   and can be examined to see if errors have occurred. This option
   300   generates slower code than the default abort policy.
   301 
   302 DEBUG                    default: NOT defined
   303   The DEBUG setting is mainly intended for people trying to modify
   304   this code or diagnose problems when porting to new platforms.
   305   However, it may also be able to better isolate user errors than just
   306   using runtime checks.  The assertions in the check routines spell
   307   out in more detail the assumptions and invariants underlying the
   308   algorithms.  The checking is fairly extensive, and will slow down
   309   execution noticeably. Calling malloc_stats or mallinfo with DEBUG
   310   set will attempt to check every non-mmapped allocated and free chunk
   311   in the course of computing the summaries.
   312 
   313 ABORT_ON_ASSERT_FAILURE   default: defined as 1 (true)
   314   Debugging assertion failures can be nearly impossible if your
   315   version of the assert macro causes malloc to be called, which will
   316   lead to a cascade of further failures, blowing the runtime stack.
   317   ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(),
   318   which will usually make debugging easier.
   319 
   320 MALLOC_FAILURE_ACTION     default: sets errno to ENOMEM, or no-op on win32
   321   The action to take before "return 0" when malloc fails to be able to
   322   return memory because there is none available.
   323 
   324 HAVE_MORECORE             default: 1 (true) unless win32 or ONLY_MSPACES
   325   True if this system supports sbrk or an emulation of it.
   326 
   327 MORECORE                  default: sbrk
   328   The name of the sbrk-style system routine to call to obtain more
   329   memory.  See below for guidance on writing custom MORECORE
   330   functions. The type of the argument to sbrk/MORECORE varies across
   331   systems.  It cannot be size_t, because it supports negative
   332   arguments, so it is normally the signed type of the same width as
   333   size_t (sometimes declared as "intptr_t").  It doesn't much matter
   334   though. Internally, we only call it with arguments less than half
   335   the max value of a size_t, which should work across all reasonable
   336   possibilities, although sometimes generating compiler warnings.  See
   337   near the end of this file for guidelines for creating a custom
   338   version of MORECORE.
   339 
   340 MORECORE_CONTIGUOUS       default: 1 (true)
   341   If true, take advantage of fact that consecutive calls to MORECORE
   342   with positive arguments always return contiguous increasing
   343   addresses.  This is true of unix sbrk. It does not hurt too much to
   344   set it true anyway, since malloc copes with non-contiguities.
   345   Setting it false when definitely non-contiguous saves time
   346   and possibly wasted space it would take to discover this though.
   347 
   348 MORECORE_CANNOT_TRIM      default: NOT defined
   349   True if MORECORE cannot release space back to the system when given
   350   negative arguments. This is generally necessary only if you are
   351   using a hand-crafted MORECORE function that cannot handle negative
   352   arguments.
   353 
   354 HAVE_MMAP                 default: 1 (true)
   355   True if this system supports mmap or an emulation of it.  If so, and
   356   HAVE_MORECORE is not true, MMAP is used for all system
   357   allocation. If set and HAVE_MORECORE is true as well, MMAP is
   358   primarily used to directly allocate very large blocks. It is also
   359   used as a backup strategy in cases where MORECORE fails to provide
   360   space from system. Note: A single call to MUNMAP is assumed to be
   361   able to unmap memory that may have be allocated using multiple calls
   362   to MMAP, so long as they are adjacent.
   363 
   364 HAVE_MREMAP               default: 1 on linux, else 0
   365   If true realloc() uses mremap() to re-allocate large blocks and
   366   extend or shrink allocation spaces.
   367 
   368 MMAP_CLEARS               default: 1 on unix
   369   True if mmap clears memory so calloc doesn't need to. This is true
   370   for standard unix mmap using /dev/zero.
   371 
   372 USE_BUILTIN_FFS            default: 0 (i.e., not used)
   373   Causes malloc to use the builtin ffs() function to compute indices.
   374   Some compilers may recognize and intrinsify ffs to be faster than the
   375   supplied C version. Also, the case of x86 using gcc is special-cased
   376   to an asm instruction, so is already as fast as it can be, and so
   377   this setting has no effect. (On most x86s, the asm version is only
   378   slightly faster than the C version.)
   379 
   380 malloc_getpagesize         default: derive from system includes, or 4096.
   381   The system page size. To the extent possible, this malloc manages
   382   memory from the system in page-size units.  This may be (and
   383   usually is) a function rather than a constant. This is ignored
   384   if WIN32, where page size is determined using getSystemInfo during
   385   initialization.
   386 
   387 USE_DEV_RANDOM             default: 0 (i.e., not used)
   388   Causes malloc to use /dev/random to initialize secure magic seed for
   389   stamping footers. Otherwise, the current time is used.
   390 
   391 NO_MALLINFO                default: 0
   392   If defined, don't compile "mallinfo". This can be a simple way
   393   of dealing with mismatches between system declarations and
   394   those in this file.
   395 
   396 MALLINFO_FIELD_TYPE        default: size_t
   397   The type of the fields in the mallinfo struct. This was originally
   398   defined as "int" in SVID etc, but is more usefully defined as
   399   size_t. The value is used only if  HAVE_USR_INCLUDE_MALLOC_H is not set
   400 
   401 REALLOC_ZERO_BYTES_FREES    default: not defined
   402   This should be set if a call to realloc with zero bytes should 
   403   be the same as a call to free. Some people think it should. Otherwise, 
   404   since this malloc returns a unique pointer for malloc(0), so does 
   405   realloc(p, 0).
   406 
   407 LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H
   408 LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H,  LACKS_ERRNO_H
   409 LACKS_STDLIB_H                default: NOT defined unless on WIN32
   410   Define these if your system does not have these header files.
   411   You might need to manually insert some of the declarations they provide.
   412 
   413 DEFAULT_GRANULARITY        default: page size if MORECORE_CONTIGUOUS,
   414                                 system_info.dwAllocationGranularity in WIN32,
   415                                 otherwise 64K.
   416       Also settable using mallopt(M_GRANULARITY, x)
   417   The unit for allocating and deallocating memory from the system.  On
   418   most systems with contiguous MORECORE, there is no reason to
   419   make this more than a page. However, systems with MMAP tend to
   420   either require or encourage larger granularities.  You can increase
   421   this value to prevent system allocation functions to be called so
   422   often, especially if they are slow.  The value must be at least one
   423   page and must be a power of two.  Setting to 0 causes initialization
   424   to either page size or win32 region size.  (Note: In previous
   425   versions of malloc, the equivalent of this option was called
   426   "TOP_PAD")
   427 
   428 DEFAULT_TRIM_THRESHOLD    default: 2MB
   429       Also settable using mallopt(M_TRIM_THRESHOLD, x)
   430   The maximum amount of unused top-most memory to keep before
   431   releasing via malloc_trim in free().  Automatic trimming is mainly
   432   useful in long-lived programs using contiguous MORECORE.  Because
   433   trimming via sbrk can be slow on some systems, and can sometimes be
   434   wasteful (in cases where programs immediately afterward allocate
   435   more large chunks) the value should be high enough so that your
   436   overall system performance would improve by releasing this much
   437   memory.  As a rough guide, you might set to a value close to the
   438   average size of a process (program) running on your system.
   439   Releasing this much memory would allow such a process to run in
   440   memory.  Generally, it is worth tuning trim thresholds when a
   441   program undergoes phases where several large chunks are allocated
   442   and released in ways that can reuse each other's storage, perhaps
   443   mixed with phases where there are no such chunks at all. The trim
   444   value must be greater than page size to have any useful effect.  To
   445   disable trimming completely, you can set to MAX_SIZE_T. Note that the trick
   446   some people use of mallocing a huge space and then freeing it at
   447   program startup, in an attempt to reserve system memory, doesn't
   448   have the intended effect under automatic trimming, since that memory
   449   will immediately be returned to the system.
   450 
   451 DEFAULT_MMAP_THRESHOLD       default: 256K
   452       Also settable using mallopt(M_MMAP_THRESHOLD, x)
   453   The request size threshold for using MMAP to directly service a
   454   request. Requests of at least this size that cannot be allocated
   455   using already-existing space will be serviced via mmap.  (If enough
   456   normal freed space already exists it is used instead.)  Using mmap
   457   segregates relatively large chunks of memory so that they can be
   458   individually obtained and released from the host system. A request
   459   serviced through mmap is never reused by any other request (at least
   460   not directly; the system may just so happen to remap successive
   461   requests to the same locations).  Segregating space in this way has
   462   the benefits that: Mmapped space can always be individually released
   463   back to the system, which helps keep the system level memory demands
   464   of a long-lived program low.  Also, mapped memory doesn't become
   465   `locked' between other chunks, as can happen with normally allocated
   466   chunks, which means that even trimming via malloc_trim would not
   467   release them.  However, it has the disadvantage that the space
   468   cannot be reclaimed, consolidated, and then used to service later
   469   requests, as happens with normal chunks.  The advantages of mmap
   470   nearly always outweigh disadvantages for "large" chunks, but the
   471   value of "large" may vary across systems.  The default is an
   472   empirically derived value that works well in most systems. You can
   473   disable mmap by setting to MAX_SIZE_T.
   474 
   475 */
   476 
   477 #ifndef WIN32
   478 #ifdef _WIN32
   479 #define WIN32 1
   480 #endif /* _WIN32 */
   481 #endif /* WIN32 */
   482 #ifdef WIN32
   483 #define WIN32_LEAN_AND_MEAN
   484 #include <windows.h>
   485 #define HAVE_MMAP 1
   486 #define HAVE_MORECORE 0
   487 #define LACKS_UNISTD_H
   488 #define LACKS_SYS_PARAM_H
   489 #define LACKS_SYS_MMAN_H
   490 #define LACKS_STRING_H
   491 #define LACKS_STRINGS_H
   492 #define LACKS_SYS_TYPES_H
   493 #define LACKS_ERRNO_H
   494 #define LACKS_FCNTL_H
   495 #define MALLOC_FAILURE_ACTION
   496 #define MMAP_CLEARS 0           /* WINCE and some others apparently don't clear */
   497 #endif /* WIN32 */
   498 
   499 #if defined(DARWIN) || defined(_DARWIN)
   500 /* Mac OSX docs advise not to use sbrk; it seems better to use mmap */
   501 #ifndef HAVE_MORECORE
   502 #define HAVE_MORECORE 0
   503 #define HAVE_MMAP 1
   504 #endif /* HAVE_MORECORE */
   505 #endif /* DARWIN */
   506 
   507 #ifndef LACKS_SYS_TYPES_H
   508 #include <sys/types.h>          /* For size_t */
   509 #endif /* LACKS_SYS_TYPES_H */
   510 
   511 /* The maximum possible size_t value has all bits set */
   512 #define MAX_SIZE_T           (~(size_t)0)
   513 
   514 #ifndef ONLY_MSPACES
   515 #define ONLY_MSPACES 0
   516 #endif /* ONLY_MSPACES */
   517 #ifndef MSPACES
   518 #if ONLY_MSPACES
   519 #define MSPACES 1
   520 #else /* ONLY_MSPACES */
   521 #define MSPACES 0
   522 #endif /* ONLY_MSPACES */
   523 #endif /* MSPACES */
   524 #ifndef MALLOC_ALIGNMENT
   525 #define MALLOC_ALIGNMENT ((size_t)8U)
   526 #endif /* MALLOC_ALIGNMENT */
   527 #ifndef FOOTERS
   528 #define FOOTERS 0
   529 #endif /* FOOTERS */
   530 #ifndef ABORT
   531 #define ABORT  abort()
   532 #endif /* ABORT */
   533 #ifndef ABORT_ON_ASSERT_FAILURE
   534 #define ABORT_ON_ASSERT_FAILURE 1
   535 #endif /* ABORT_ON_ASSERT_FAILURE */
   536 #ifndef PROCEED_ON_ERROR
   537 #define PROCEED_ON_ERROR 0
   538 #endif /* PROCEED_ON_ERROR */
   539 #ifndef USE_LOCKS
   540 #define USE_LOCKS 0
   541 #endif /* USE_LOCKS */
   542 #ifndef INSECURE
   543 #define INSECURE 0
   544 #endif /* INSECURE */
   545 #ifndef HAVE_MMAP
   546 #define HAVE_MMAP 1
   547 #endif /* HAVE_MMAP */
   548 #ifndef MMAP_CLEARS
   549 #define MMAP_CLEARS 1
   550 #endif /* MMAP_CLEARS */
   551 #ifndef HAVE_MREMAP
   552 #ifdef linux
   553 #define HAVE_MREMAP 1
   554 #else /* linux */
   555 #define HAVE_MREMAP 0
   556 #endif /* linux */
   557 #endif /* HAVE_MREMAP */
   558 #ifndef MALLOC_FAILURE_ACTION
   559 #define MALLOC_FAILURE_ACTION  errno = ENOMEM;
   560 #endif /* MALLOC_FAILURE_ACTION */
   561 #ifndef HAVE_MORECORE
   562 #if ONLY_MSPACES
   563 #define HAVE_MORECORE 0
   564 #else /* ONLY_MSPACES */
   565 #define HAVE_MORECORE 1
   566 #endif /* ONLY_MSPACES */
   567 #endif /* HAVE_MORECORE */
   568 #if !HAVE_MORECORE
   569 #define MORECORE_CONTIGUOUS 0
   570 #else /* !HAVE_MORECORE */
   571 #ifndef MORECORE
   572 #define MORECORE sbrk
   573 #endif /* MORECORE */
   574 #ifndef MORECORE_CONTIGUOUS
   575 #define MORECORE_CONTIGUOUS 1
   576 #endif /* MORECORE_CONTIGUOUS */
   577 #endif /* HAVE_MORECORE */
   578 #ifndef DEFAULT_GRANULARITY
   579 #if MORECORE_CONTIGUOUS
   580 #define DEFAULT_GRANULARITY (0) /* 0 means to compute in init_mparams */
   581 #else /* MORECORE_CONTIGUOUS */
   582 #define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U)
   583 #endif /* MORECORE_CONTIGUOUS */
   584 #endif /* DEFAULT_GRANULARITY */
   585 #ifndef DEFAULT_TRIM_THRESHOLD
   586 #ifndef MORECORE_CANNOT_TRIM
   587 #define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U)
   588 #else /* MORECORE_CANNOT_TRIM */
   589 #define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T
   590 #endif /* MORECORE_CANNOT_TRIM */
   591 #endif /* DEFAULT_TRIM_THRESHOLD */
   592 #ifndef DEFAULT_MMAP_THRESHOLD
   593 #if HAVE_MMAP
   594 #define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U)
   595 #else /* HAVE_MMAP */
   596 #define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T
   597 #endif /* HAVE_MMAP */
   598 #endif /* DEFAULT_MMAP_THRESHOLD */
   599 #ifndef USE_BUILTIN_FFS
   600 #define USE_BUILTIN_FFS 0
   601 #endif /* USE_BUILTIN_FFS */
   602 #ifndef USE_DEV_RANDOM
   603 #define USE_DEV_RANDOM 0
   604 #endif /* USE_DEV_RANDOM */
   605 #ifndef NO_MALLINFO
   606 #define NO_MALLINFO 0
   607 #endif /* NO_MALLINFO */
   608 #ifndef MALLINFO_FIELD_TYPE
   609 #define MALLINFO_FIELD_TYPE size_t
   610 #endif /* MALLINFO_FIELD_TYPE */
   611 
   612 #define memset	SDL_memset
   613 #define malloc	SDL_malloc
   614 #define calloc	SDL_calloc
   615 #define realloc	SDL_realloc
   616 #define free	SDL_free
   617 
   618 /*
   619   mallopt tuning options.  SVID/XPG defines four standard parameter
   620   numbers for mallopt, normally defined in malloc.h.  None of these
   621   are used in this malloc, so setting them has no effect. But this
   622   malloc does support the following options.
   623 */
   624 
   625 #define M_TRIM_THRESHOLD     (-1)
   626 #define M_GRANULARITY        (-2)
   627 #define M_MMAP_THRESHOLD     (-3)
   628 
   629 /* ------------------------ Mallinfo declarations ------------------------ */
   630 
   631 #if !NO_MALLINFO
   632 /*
   633   This version of malloc supports the standard SVID/XPG mallinfo
   634   routine that returns a struct containing usage properties and
   635   statistics. It should work on any system that has a
   636   /usr/include/malloc.h defining struct mallinfo.  The main
   637   declaration needed is the mallinfo struct that is returned (by-copy)
   638   by mallinfo().  The malloinfo struct contains a bunch of fields that
   639   are not even meaningful in this version of malloc.  These fields are
   640   are instead filled by mallinfo() with other numbers that might be of
   641   interest.
   642 
   643   HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
   644   /usr/include/malloc.h file that includes a declaration of struct
   645   mallinfo.  If so, it is included; else a compliant version is
   646   declared below.  These must be precisely the same for mallinfo() to
   647   work.  The original SVID version of this struct, defined on most
   648   systems with mallinfo, declares all fields as ints. But some others
   649   define as unsigned long. If your system defines the fields using a
   650   type of different width than listed here, you MUST #include your
   651   system version and #define HAVE_USR_INCLUDE_MALLOC_H.
   652 */
   653 
   654 /* #define HAVE_USR_INCLUDE_MALLOC_H */
   655 
   656 #ifdef HAVE_USR_INCLUDE_MALLOC_H
   657 #include "/usr/include/malloc.h"
   658 #else /* HAVE_USR_INCLUDE_MALLOC_H */
   659 
   660 struct mallinfo
   661 {
   662     MALLINFO_FIELD_TYPE arena;  /* non-mmapped space allocated from system */
   663     MALLINFO_FIELD_TYPE ordblks;        /* number of free chunks */
   664     MALLINFO_FIELD_TYPE smblks; /* always 0 */
   665     MALLINFO_FIELD_TYPE hblks;  /* always 0 */
   666     MALLINFO_FIELD_TYPE hblkhd; /* space in mmapped regions */
   667     MALLINFO_FIELD_TYPE usmblks;        /* maximum total allocated space */
   668     MALLINFO_FIELD_TYPE fsmblks;        /* always 0 */
   669     MALLINFO_FIELD_TYPE uordblks;       /* total allocated space */
   670     MALLINFO_FIELD_TYPE fordblks;       /* total free space */
   671     MALLINFO_FIELD_TYPE keepcost;       /* releasable (via malloc_trim) space */
   672 };
   673 
   674 #endif /* HAVE_USR_INCLUDE_MALLOC_H */
   675 #endif /* NO_MALLINFO */
   676 
   677 #ifdef __cplusplus
   678 extern "C"
   679 {
   680 #endif                          /* __cplusplus */
   681 
   682 #if !ONLY_MSPACES
   683 
   684 /* ------------------- Declarations of public routines ------------------- */
   685 
   686 #ifndef USE_DL_PREFIX
   687 #define dlcalloc               calloc
   688 #define dlfree                 free
   689 #define dlmalloc               malloc
   690 #define dlmemalign             memalign
   691 #define dlrealloc              realloc
   692 #define dlvalloc               valloc
   693 #define dlpvalloc              pvalloc
   694 #define dlmallinfo             mallinfo
   695 #define dlmallopt              mallopt
   696 #define dlmalloc_trim          malloc_trim
   697 #define dlmalloc_stats         malloc_stats
   698 #define dlmalloc_usable_size   malloc_usable_size
   699 #define dlmalloc_footprint     malloc_footprint
   700 #define dlmalloc_max_footprint malloc_max_footprint
   701 #define dlindependent_calloc   independent_calloc
   702 #define dlindependent_comalloc independent_comalloc
   703 #endif                          /* USE_DL_PREFIX */
   704 
   705 
   706 /*
   707   malloc(size_t n)
   708   Returns a pointer to a newly allocated chunk of at least n bytes, or
   709   null if no space is available, in which case errno is set to ENOMEM
   710   on ANSI C systems.
   711 
   712   If n is zero, malloc returns a minimum-sized chunk. (The minimum
   713   size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
   714   systems.)  Note that size_t is an unsigned type, so calls with
   715   arguments that would be negative if signed are interpreted as
   716   requests for huge amounts of space, which will often fail. The
   717   maximum supported value of n differs across systems, but is in all
   718   cases less than the maximum representable value of a size_t.
   719 */
   720     void *dlmalloc(size_t);
   721 
   722 /*
   723   free(void* p)
   724   Releases the chunk of memory pointed to by p, that had been previously
   725   allocated using malloc or a related routine such as realloc.
   726   It has no effect if p is null. If p was not malloced or already
   727   freed, free(p) will by default cause the current program to abort.
   728 */
   729     void dlfree(void *);
   730 
   731 /*
   732   calloc(size_t n_elements, size_t element_size);
   733   Returns a pointer to n_elements * element_size bytes, with all locations
   734   set to zero.
   735 */
   736     void *dlcalloc(size_t, size_t);
   737 
   738 /*
   739   realloc(void* p, size_t n)
   740   Returns a pointer to a chunk of size n that contains the same data
   741   as does chunk p up to the minimum of (n, p's size) bytes, or null
   742   if no space is available.
   743 
   744   The returned pointer may or may not be the same as p. The algorithm
   745   prefers extending p in most cases when possible, otherwise it
   746   employs the equivalent of a malloc-copy-free sequence.
   747 
   748   If p is null, realloc is equivalent to malloc.
   749 
   750   If space is not available, realloc returns null, errno is set (if on
   751   ANSI) and p is NOT freed.
   752 
   753   if n is for fewer bytes than already held by p, the newly unused
   754   space is lopped off and freed if possible.  realloc with a size
   755   argument of zero (re)allocates a minimum-sized chunk.
   756 
   757   The old unix realloc convention of allowing the last-free'd chunk
   758   to be used as an argument to realloc is not supported.
   759 */
   760 
   761     void *dlrealloc(void *, size_t);
   762 
   763 /*
   764   memalign(size_t alignment, size_t n);
   765   Returns a pointer to a newly allocated chunk of n bytes, aligned
   766   in accord with the alignment argument.
   767 
   768   The alignment argument should be a power of two. If the argument is
   769   not a power of two, the nearest greater power is used.
   770   8-byte alignment is guaranteed by normal malloc calls, so don't
   771   bother calling memalign with an argument of 8 or less.
   772 
   773   Overreliance on memalign is a sure way to fragment space.
   774 */
   775     void *dlmemalign(size_t, size_t);
   776 
   777 /*
   778   valloc(size_t n);
   779   Equivalent to memalign(pagesize, n), where pagesize is the page
   780   size of the system. If the pagesize is unknown, 4096 is used.
   781 */
   782     void *dlvalloc(size_t);
   783 
   784 /*
   785   mallopt(int parameter_number, int parameter_value)
   786   Sets tunable parameters The format is to provide a
   787   (parameter-number, parameter-value) pair.  mallopt then sets the
   788   corresponding parameter to the argument value if it can (i.e., so
   789   long as the value is meaningful), and returns 1 if successful else
   790   0.  SVID/XPG/ANSI defines four standard param numbers for mallopt,
   791   normally defined in malloc.h.  None of these are use in this malloc,
   792   so setting them has no effect. But this malloc also supports other
   793   options in mallopt. See below for details.  Briefly, supported
   794   parameters are as follows (listed defaults are for "typical"
   795   configurations).
   796 
   797   Symbol            param #  default    allowed param values
   798   M_TRIM_THRESHOLD     -1   2*1024*1024   any   (MAX_SIZE_T disables)
   799   M_GRANULARITY        -2     page size   any power of 2 >= page size
   800   M_MMAP_THRESHOLD     -3      256*1024   any   (or 0 if no MMAP support)
   801 */
   802     int dlmallopt(int, int);
   803 
   804 /*
   805   malloc_footprint();
   806   Returns the number of bytes obtained from the system.  The total
   807   number of bytes allocated by malloc, realloc etc., is less than this
   808   value. Unlike mallinfo, this function returns only a precomputed
   809   result, so can be called frequently to monitor memory consumption.
   810   Even if locks are otherwise defined, this function does not use them,
   811   so results might not be up to date.
   812 */
   813     size_t dlmalloc_footprint(void);
   814 
   815 /*
   816   malloc_max_footprint();
   817   Returns the maximum number of bytes obtained from the system. This
   818   value will be greater than current footprint if deallocated space
   819   has been reclaimed by the system. The peak number of bytes allocated
   820   by malloc, realloc etc., is less than this value. Unlike mallinfo,
   821   this function returns only a precomputed result, so can be called
   822   frequently to monitor memory consumption.  Even if locks are
   823   otherwise defined, this function does not use them, so results might
   824   not be up to date.
   825 */
   826     size_t dlmalloc_max_footprint(void);
   827 
   828 #if !NO_MALLINFO
   829 /*
   830   mallinfo()
   831   Returns (by copy) a struct containing various summary statistics:
   832 
   833   arena:     current total non-mmapped bytes allocated from system
   834   ordblks:   the number of free chunks
   835   smblks:    always zero.
   836   hblks:     current number of mmapped regions
   837   hblkhd:    total bytes held in mmapped regions
   838   usmblks:   the maximum total allocated space. This will be greater
   839                 than current total if trimming has occurred.
   840   fsmblks:   always zero
   841   uordblks:  current total allocated space (normal or mmapped)
   842   fordblks:  total free space
   843   keepcost:  the maximum number of bytes that could ideally be released
   844                back to system via malloc_trim. ("ideally" means that
   845                it ignores page restrictions etc.)
   846 
   847   Because these fields are ints, but internal bookkeeping may
   848   be kept as longs, the reported values may wrap around zero and
   849   thus be inaccurate.
   850 */
   851     struct mallinfo dlmallinfo(void);
   852 #endif                          /* NO_MALLINFO */
   853 
   854 /*
   855   independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
   856 
   857   independent_calloc is similar to calloc, but instead of returning a
   858   single cleared space, it returns an array of pointers to n_elements
   859   independent elements that can hold contents of size elem_size, each
   860   of which starts out cleared, and can be independently freed,
   861   realloc'ed etc. The elements are guaranteed to be adjacently
   862   allocated (this is not guaranteed to occur with multiple callocs or
   863   mallocs), which may also improve cache locality in some
   864   applications.
   865 
   866   The "chunks" argument is optional (i.e., may be null, which is
   867   probably the most typical usage). If it is null, the returned array
   868   is itself dynamically allocated and should also be freed when it is
   869   no longer needed. Otherwise, the chunks array must be of at least
   870   n_elements in length. It is filled in with the pointers to the
   871   chunks.
   872 
   873   In either case, independent_calloc returns this pointer array, or
   874   null if the allocation failed.  If n_elements is zero and "chunks"
   875   is null, it returns a chunk representing an array with zero elements
   876   (which should be freed if not wanted).
   877 
   878   Each element must be individually freed when it is no longer
   879   needed. If you'd like to instead be able to free all at once, you
   880   should instead use regular calloc and assign pointers into this
   881   space to represent elements.  (In this case though, you cannot
   882   independently free elements.)
   883 
   884   independent_calloc simplifies and speeds up implementations of many
   885   kinds of pools.  It may also be useful when constructing large data
   886   structures that initially have a fixed number of fixed-sized nodes,
   887   but the number is not known at compile time, and some of the nodes
   888   may later need to be freed. For example:
   889 
   890   struct Node { int item; struct Node* next; };
   891 
   892   struct Node* build_list() {
   893     struct Node** pool;
   894     int n = read_number_of_nodes_needed();
   895     if (n <= 0) return 0;
   896     pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
   897     if (pool == 0) die();
   898     // organize into a linked list...
   899     struct Node* first = pool[0];
   900     for (i = 0; i < n-1; ++i)
   901       pool[i]->next = pool[i+1];
   902     free(pool);     // Can now free the array (or not, if it is needed later)
   903     return first;
   904   }
   905 */
   906     void **dlindependent_calloc(size_t, size_t, void **);
   907 
   908 /*
   909   independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
   910 
   911   independent_comalloc allocates, all at once, a set of n_elements
   912   chunks with sizes indicated in the "sizes" array.    It returns
   913   an array of pointers to these elements, each of which can be
   914   independently freed, realloc'ed etc. The elements are guaranteed to
   915   be adjacently allocated (this is not guaranteed to occur with
   916   multiple callocs or mallocs), which may also improve cache locality
   917   in some applications.
   918 
   919   The "chunks" argument is optional (i.e., may be null). If it is null
   920   the returned array is itself dynamically allocated and should also
   921   be freed when it is no longer needed. Otherwise, the chunks array
   922   must be of at least n_elements in length. It is filled in with the
   923   pointers to the chunks.
   924 
   925   In either case, independent_comalloc returns this pointer array, or
   926   null if the allocation failed.  If n_elements is zero and chunks is
   927   null, it returns a chunk representing an array with zero elements
   928   (which should be freed if not wanted).
   929 
   930   Each element must be individually freed when it is no longer
   931   needed. If you'd like to instead be able to free all at once, you
   932   should instead use a single regular malloc, and assign pointers at
   933   particular offsets in the aggregate space. (In this case though, you
   934   cannot independently free elements.)
   935 
   936   independent_comallac differs from independent_calloc in that each
   937   element may have a different size, and also that it does not
   938   automatically clear elements.
   939 
   940   independent_comalloc can be used to speed up allocation in cases
   941   where several structs or objects must always be allocated at the
   942   same time.  For example:
   943 
   944   struct Head { ... }
   945   struct Foot { ... }
   946 
   947   void send_message(char* msg) {
   948     int msglen = strlen(msg);
   949     size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
   950     void* chunks[3];
   951     if (independent_comalloc(3, sizes, chunks) == 0)
   952       die();
   953     struct Head* head = (struct Head*)(chunks[0]);
   954     char*        body = (char*)(chunks[1]);
   955     struct Foot* foot = (struct Foot*)(chunks[2]);
   956     // ...
   957   }
   958 
   959   In general though, independent_comalloc is worth using only for
   960   larger values of n_elements. For small values, you probably won't
   961   detect enough difference from series of malloc calls to bother.
   962 
   963   Overuse of independent_comalloc can increase overall memory usage,
   964   since it cannot reuse existing noncontiguous small chunks that
   965   might be available for some of the elements.
   966 */
   967     void **dlindependent_comalloc(size_t, size_t *, void **);
   968 
   969 
   970 /*
   971   pvalloc(size_t n);
   972   Equivalent to valloc(minimum-page-that-holds(n)), that is,
   973   round up n to nearest pagesize.
   974  */
   975     void *dlpvalloc(size_t);
   976 
   977 /*
   978   malloc_trim(size_t pad);
   979 
   980   If possible, gives memory back to the system (via negative arguments
   981   to sbrk) if there is unused memory at the `high' end of the malloc
   982   pool or in unused MMAP segments. You can call this after freeing
   983   large blocks of memory to potentially reduce the system-level memory
   984   requirements of a program. However, it cannot guarantee to reduce
   985   memory. Under some allocation patterns, some large free blocks of
   986   memory will be locked between two used chunks, so they cannot be
   987   given back to the system.
   988 
   989   The `pad' argument to malloc_trim represents the amount of free
   990   trailing space to leave untrimmed. If this argument is zero, only
   991   the minimum amount of memory to maintain internal data structures
   992   will be left. Non-zero arguments can be supplied to maintain enough
   993   trailing space to service future expected allocations without having
   994   to re-obtain memory from the system.
   995 
   996   Malloc_trim returns 1 if it actually released any memory, else 0.
   997 */
   998     int dlmalloc_trim(size_t);
   999 
  1000 /*
  1001   malloc_usable_size(void* p);
  1002 
  1003   Returns the number of bytes you can actually use in
  1004   an allocated chunk, which may be more than you requested (although
  1005   often not) due to alignment and minimum size constraints.
  1006   You can use this many bytes without worrying about
  1007   overwriting other allocated objects. This is not a particularly great
  1008   programming practice. malloc_usable_size can be more useful in
  1009   debugging and assertions, for example:
  1010 
  1011   p = malloc(n);
  1012   assert(malloc_usable_size(p) >= 256);
  1013 */
  1014     size_t dlmalloc_usable_size(void *);
  1015 
  1016 /*
  1017   malloc_stats();
  1018   Prints on stderr the amount of space obtained from the system (both
  1019   via sbrk and mmap), the maximum amount (which may be more than
  1020   current if malloc_trim and/or munmap got called), and the current
  1021   number of bytes allocated via malloc (or realloc, etc) but not yet
  1022   freed. Note that this is the number of bytes allocated, not the
  1023   number requested. It will be larger than the number requested
  1024   because of alignment and bookkeeping overhead. Because it includes
  1025   alignment wastage as being in use, this figure may be greater than
  1026   zero even when no user-level chunks are allocated.
  1027 
  1028   The reported current and maximum system memory can be inaccurate if
  1029   a program makes other calls to system memory allocation functions
  1030   (normally sbrk) outside of malloc.
  1031 
  1032   malloc_stats prints only the most commonly interesting statistics.
  1033   More information can be obtained by calling mallinfo.
  1034 */
  1035     void dlmalloc_stats(void);
  1036 
  1037 #endif                          /* ONLY_MSPACES */
  1038 
  1039 #if MSPACES
  1040 
  1041 /*
  1042   mspace is an opaque type representing an independent
  1043   region of space that supports mspace_malloc, etc.
  1044 */
  1045     typedef void *mspace;
  1046 
  1047 /*
  1048   create_mspace creates and returns a new independent space with the
  1049   given initial capacity, or, if 0, the default granularity size.  It
  1050   returns null if there is no system memory available to create the
  1051   space.  If argument locked is non-zero, the space uses a separate
  1052   lock to control access. The capacity of the space will grow
  1053   dynamically as needed to service mspace_malloc requests.  You can
  1054   control the sizes of incremental increases of this space by
  1055   compiling with a different DEFAULT_GRANULARITY or dynamically
  1056   setting with mallopt(M_GRANULARITY, value).
  1057 */
  1058     mspace create_mspace(size_t capacity, int locked);
  1059 
  1060 /*
  1061   destroy_mspace destroys the given space, and attempts to return all
  1062   of its memory back to the system, returning the total number of
  1063   bytes freed. After destruction, the results of access to all memory
  1064   used by the space become undefined.
  1065 */
  1066     size_t destroy_mspace(mspace msp);
  1067 
  1068 /*
  1069   create_mspace_with_base uses the memory supplied as the initial base
  1070   of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
  1071   space is used for bookkeeping, so the capacity must be at least this
  1072   large. (Otherwise 0 is returned.) When this initial space is
  1073   exhausted, additional memory will be obtained from the system.
  1074   Destroying this space will deallocate all additionally allocated
  1075   space (if possible) but not the initial base.
  1076 */
  1077     mspace create_mspace_with_base(void *base, size_t capacity, int locked);
  1078 
  1079 /*
  1080   mspace_malloc behaves as malloc, but operates within
  1081   the given space.
  1082 */
  1083     void *mspace_malloc(mspace msp, size_t bytes);
  1084 
  1085 /*
  1086   mspace_free behaves as free, but operates within
  1087   the given space.
  1088 
  1089   If compiled with FOOTERS==1, mspace_free is not actually needed.
  1090   free may be called instead of mspace_free because freed chunks from
  1091   any space are handled by their originating spaces.
  1092 */
  1093     void mspace_free(mspace msp, void *mem);
  1094 
  1095 /*
  1096   mspace_realloc behaves as realloc, but operates within
  1097   the given space.
  1098 
  1099   If compiled with FOOTERS==1, mspace_realloc is not actually
  1100   needed.  realloc may be called instead of mspace_realloc because
  1101   realloced chunks from any space are handled by their originating
  1102   spaces.
  1103 */
  1104     void *mspace_realloc(mspace msp, void *mem, size_t newsize);
  1105 
  1106 /*
  1107   mspace_calloc behaves as calloc, but operates within
  1108   the given space.
  1109 */
  1110     void *mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
  1111 
  1112 /*
  1113   mspace_memalign behaves as memalign, but operates within
  1114   the given space.
  1115 */
  1116     void *mspace_memalign(mspace msp, size_t alignment, size_t bytes);
  1117 
  1118 /*
  1119   mspace_independent_calloc behaves as independent_calloc, but
  1120   operates within the given space.
  1121 */
  1122     void **mspace_independent_calloc(mspace msp, size_t n_elements,
  1123                                      size_t elem_size, void *chunks[]);
  1124 
  1125 /*
  1126   mspace_independent_comalloc behaves as independent_comalloc, but
  1127   operates within the given space.
  1128 */
  1129     void **mspace_independent_comalloc(mspace msp, size_t n_elements,
  1130                                        size_t sizes[], void *chunks[]);
  1131 
  1132 /*
  1133   mspace_footprint() returns the number of bytes obtained from the
  1134   system for this space.
  1135 */
  1136     size_t mspace_footprint(mspace msp);
  1137 
  1138 /*
  1139   mspace_max_footprint() returns the peak number of bytes obtained from the
  1140   system for this space.
  1141 */
  1142     size_t mspace_max_footprint(mspace msp);
  1143 
  1144 
  1145 #if !NO_MALLINFO
  1146 /*
  1147   mspace_mallinfo behaves as mallinfo, but reports properties of
  1148   the given space.
  1149 */
  1150     struct mallinfo mspace_mallinfo(mspace msp);
  1151 #endif                          /* NO_MALLINFO */
  1152 
  1153 /*
  1154   mspace_malloc_stats behaves as malloc_stats, but reports
  1155   properties of the given space.
  1156 */
  1157     void mspace_malloc_stats(mspace msp);
  1158 
  1159 /*
  1160   mspace_trim behaves as malloc_trim, but
  1161   operates within the given space.
  1162 */
  1163     int mspace_trim(mspace msp, size_t pad);
  1164 
  1165 /*
  1166   An alias for mallopt.
  1167 */
  1168     int mspace_mallopt(int, int);
  1169 
  1170 #endif                          /* MSPACES */
  1171 
  1172 #ifdef __cplusplus
  1173 };                              /* end of extern "C" */
  1174 #endif /* __cplusplus */
  1175 
  1176 /*
  1177   ========================================================================
  1178   To make a fully customizable malloc.h header file, cut everything
  1179   above this line, put into file malloc.h, edit to suit, and #include it
  1180   on the next line, as well as in programs that use this malloc.
  1181   ========================================================================
  1182 */
  1183 
  1184 /* #include "malloc.h" */
  1185 
  1186 /*------------------------------ internal #includes ---------------------- */
  1187 
  1188 #ifdef _MSC_VER
  1189 #pragma warning( disable : 4146 )       /* no "unsigned" warnings */
  1190 #endif /* _MSC_VER */
  1191 
  1192 #ifndef LACKS_STDIO_H
  1193 #include <stdio.h>              /* for printing in malloc_stats */
  1194 #endif
  1195 
  1196 #ifndef LACKS_ERRNO_H
  1197 #include <errno.h>              /* for MALLOC_FAILURE_ACTION */
  1198 #endif /* LACKS_ERRNO_H */
  1199 #if FOOTERS
  1200 #include <time.h>               /* for magic initialization */
  1201 #endif /* FOOTERS */
  1202 #ifndef LACKS_STDLIB_H
  1203 #include <stdlib.h>             /* for abort() */
  1204 #endif /* LACKS_STDLIB_H */
  1205 #ifdef DEBUG
  1206 #if ABORT_ON_ASSERT_FAILURE
  1207 #define assert(x) if(!(x)) ABORT
  1208 #else /* ABORT_ON_ASSERT_FAILURE */
  1209 #include <assert.h>
  1210 #endif /* ABORT_ON_ASSERT_FAILURE */
  1211 #else /* DEBUG */
  1212 #define assert(x)
  1213 #endif /* DEBUG */
  1214 #ifndef LACKS_STRING_H
  1215 #include <string.h>             /* for memset etc */
  1216 #endif /* LACKS_STRING_H */
  1217 #if USE_BUILTIN_FFS
  1218 #ifndef LACKS_STRINGS_H
  1219 #include <strings.h>            /* for ffs */
  1220 #endif /* LACKS_STRINGS_H */
  1221 #endif /* USE_BUILTIN_FFS */
  1222 #if HAVE_MMAP
  1223 #ifndef LACKS_SYS_MMAN_H
  1224 #include <sys/mman.h>           /* for mmap */
  1225 #endif /* LACKS_SYS_MMAN_H */
  1226 #ifndef LACKS_FCNTL_H
  1227 #include <fcntl.h>
  1228 #endif /* LACKS_FCNTL_H */
  1229 #endif /* HAVE_MMAP */
  1230 #if HAVE_MORECORE
  1231 #ifndef LACKS_UNISTD_H
  1232 #include <unistd.h>             /* for sbrk */
  1233 #else /* LACKS_UNISTD_H */
  1234 #if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
  1235 extern void *sbrk(ptrdiff_t);
  1236 #endif /* FreeBSD etc */
  1237 #endif /* LACKS_UNISTD_H */
  1238 #endif /* HAVE_MMAP */
  1239 
  1240 #ifndef WIN32
  1241 #ifndef malloc_getpagesize
  1242 #  ifdef _SC_PAGESIZE           /* some SVR4 systems omit an underscore */
  1243 #    ifndef _SC_PAGE_SIZE
  1244 #      define _SC_PAGE_SIZE _SC_PAGESIZE
  1245 #    endif
  1246 #  endif
  1247 #  ifdef _SC_PAGE_SIZE
  1248 #    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
  1249 #  else
  1250 #    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
  1251 extern size_t getpagesize();
  1252 #      define malloc_getpagesize getpagesize()
  1253 #    else
  1254 #      ifdef WIN32              /* use supplied emulation of getpagesize */
  1255 #        define malloc_getpagesize getpagesize()
  1256 #      else
  1257 #        ifndef LACKS_SYS_PARAM_H
  1258 #          include <sys/param.h>
  1259 #        endif
  1260 #        ifdef EXEC_PAGESIZE
  1261 #          define malloc_getpagesize EXEC_PAGESIZE
  1262 #        else
  1263 #          ifdef NBPG
  1264 #            ifndef CLSIZE
  1265 #              define malloc_getpagesize NBPG
  1266 #            else
  1267 #              define malloc_getpagesize (NBPG * CLSIZE)
  1268 #            endif
  1269 #          else
  1270 #            ifdef NBPC
  1271 #              define malloc_getpagesize NBPC
  1272 #            else
  1273 #              ifdef PAGESIZE
  1274 #                define malloc_getpagesize PAGESIZE
  1275 #              else /* just guess */
  1276 #                define malloc_getpagesize ((size_t)4096U)
  1277 #              endif
  1278 #            endif
  1279 #          endif
  1280 #        endif
  1281 #      endif
  1282 #    endif
  1283 #  endif
  1284 #endif
  1285 #endif
  1286 
  1287 /* ------------------- size_t and alignment properties -------------------- */
  1288 
  1289 /* The byte and bit size of a size_t */
  1290 #define SIZE_T_SIZE         (sizeof(size_t))
  1291 #define SIZE_T_BITSIZE      (sizeof(size_t) << 3)
  1292 
  1293 /* Some constants coerced to size_t */
  1294 /* Annoying but necessary to avoid errors on some plaftorms */
  1295 #define SIZE_T_ZERO         ((size_t)0)
  1296 #define SIZE_T_ONE          ((size_t)1)
  1297 #define SIZE_T_TWO          ((size_t)2)
  1298 #define TWO_SIZE_T_SIZES    (SIZE_T_SIZE<<1)
  1299 #define FOUR_SIZE_T_SIZES   (SIZE_T_SIZE<<2)
  1300 #define SIX_SIZE_T_SIZES    (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES)
  1301 #define HALF_MAX_SIZE_T     (MAX_SIZE_T / 2U)
  1302 
  1303 /* The bit mask value corresponding to MALLOC_ALIGNMENT */
  1304 #define CHUNK_ALIGN_MASK    (MALLOC_ALIGNMENT - SIZE_T_ONE)
  1305 
  1306 /* True if address a has acceptable alignment */
  1307 #define is_aligned(A)       (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0)
  1308 
  1309 /* the number of bytes to offset an address to align it */
  1310 #define align_offset(A)\
  1311  ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\
  1312   ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK))
  1313 
  1314 /* -------------------------- MMAP preliminaries ------------------------- */
  1315 
  1316 /*
  1317    If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and
  1318    checks to fail so compiler optimizer can delete code rather than
  1319    using so many "#if"s.
  1320 */
  1321 
  1322 
  1323 /* MORECORE and MMAP must return MFAIL on failure */
  1324 #define MFAIL                ((void*)(MAX_SIZE_T))
  1325 #define CMFAIL               ((char*)(MFAIL))   /* defined for convenience */
  1326 
  1327 #if !HAVE_MMAP
  1328 #define IS_MMAPPED_BIT       (SIZE_T_ZERO)
  1329 #define USE_MMAP_BIT         (SIZE_T_ZERO)
  1330 #define CALL_MMAP(s)         MFAIL
  1331 #define CALL_MUNMAP(a, s)    (-1)
  1332 #define DIRECT_MMAP(s)       MFAIL
  1333 
  1334 #else /* HAVE_MMAP */
  1335 #define IS_MMAPPED_BIT       (SIZE_T_ONE)
  1336 #define USE_MMAP_BIT         (SIZE_T_ONE)
  1337 
  1338 #ifndef WIN32
  1339 #define CALL_MUNMAP(a, s)    munmap((a), (s))
  1340 #define MMAP_PROT            (PROT_READ|PROT_WRITE)
  1341 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
  1342 #define MAP_ANONYMOUS        MAP_ANON
  1343 #endif /* MAP_ANON */
  1344 #ifdef MAP_ANONYMOUS
  1345 #define MMAP_FLAGS           (MAP_PRIVATE|MAP_ANONYMOUS)
  1346 #define CALL_MMAP(s)         mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
  1347 #else /* MAP_ANONYMOUS */
  1348 /*
  1349    Nearly all versions of mmap support MAP_ANONYMOUS, so the following
  1350    is unlikely to be needed, but is supplied just in case.
  1351 */
  1352 #define MMAP_FLAGS           (MAP_PRIVATE)
  1353 static int dev_zero_fd = -1;    /* Cached file descriptor for /dev/zero. */
  1354 #define CALL_MMAP(s) ((dev_zero_fd < 0) ? \
  1355            (dev_zero_fd = open("/dev/zero", O_RDWR), \
  1356             mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \
  1357             mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0))
  1358 #endif /* MAP_ANONYMOUS */
  1359 
  1360 #define DIRECT_MMAP(s)       CALL_MMAP(s)
  1361 #else /* WIN32 */
  1362 
  1363 /* Win32 MMAP via VirtualAlloc */
  1364 static void *
  1365 win32mmap(size_t size)
  1366 {
  1367     void *ptr =
  1368         VirtualAlloc(0, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
  1369     return (ptr != 0) ? ptr : MFAIL;
  1370 }
  1371 
  1372 /* For direct MMAP, use MEM_TOP_DOWN to minimize interference */
  1373 static void *
  1374 win32direct_mmap(size_t size)
  1375 {
  1376     void *ptr = VirtualAlloc(0, size, MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN,
  1377                              PAGE_READWRITE);
  1378     return (ptr != 0) ? ptr : MFAIL;
  1379 }
  1380 
  1381 /* This function supports releasing coalesed segments */
  1382 static int
  1383 win32munmap(void *ptr, size_t size)
  1384 {
  1385     MEMORY_BASIC_INFORMATION minfo;
  1386     char *cptr = ptr;
  1387     while (size) {
  1388         if (VirtualQuery(cptr, &minfo, sizeof(minfo)) == 0)
  1389             return -1;
  1390         if (minfo.BaseAddress != cptr || minfo.AllocationBase != cptr ||
  1391             minfo.State != MEM_COMMIT || minfo.RegionSize > size)
  1392             return -1;
  1393         if (VirtualFree(cptr, 0, MEM_RELEASE) == 0)
  1394             return -1;
  1395         cptr += minfo.RegionSize;
  1396         size -= minfo.RegionSize;
  1397     }
  1398     return 0;
  1399 }
  1400 
  1401 #define CALL_MMAP(s)         win32mmap(s)
  1402 #define CALL_MUNMAP(a, s)    win32munmap((a), (s))
  1403 #define DIRECT_MMAP(s)       win32direct_mmap(s)
  1404 #endif /* WIN32 */
  1405 #endif /* HAVE_MMAP */
  1406 
  1407 #if HAVE_MMAP && HAVE_MREMAP
  1408 #define CALL_MREMAP(addr, osz, nsz, mv) mremap((addr), (osz), (nsz), (mv))
  1409 #else /* HAVE_MMAP && HAVE_MREMAP */
  1410 #define CALL_MREMAP(addr, osz, nsz, mv) MFAIL
  1411 #endif /* HAVE_MMAP && HAVE_MREMAP */
  1412 
  1413 #if HAVE_MORECORE
  1414 #define CALL_MORECORE(S)     MORECORE(S)
  1415 #else /* HAVE_MORECORE */
  1416 #define CALL_MORECORE(S)     MFAIL
  1417 #endif /* HAVE_MORECORE */
  1418 
  1419 /* mstate bit set if continguous morecore disabled or failed */
  1420 #define USE_NONCONTIGUOUS_BIT (4U)
  1421 
  1422 /* segment bit set in create_mspace_with_base */
  1423 #define EXTERN_BIT            (8U)
  1424 
  1425 
  1426 /* --------------------------- Lock preliminaries ------------------------ */
  1427 
  1428 #if USE_LOCKS
  1429 
  1430 /*
  1431   When locks are defined, there are up to two global locks:
  1432 
  1433   * If HAVE_MORECORE, morecore_mutex protects sequences of calls to
  1434     MORECORE.  In many cases sys_alloc requires two calls, that should
  1435     not be interleaved with calls by other threads.  This does not
  1436     protect against direct calls to MORECORE by other threads not
  1437     using this lock, so there is still code to cope the best we can on
  1438     interference.
  1439 
  1440   * magic_init_mutex ensures that mparams.magic and other
  1441     unique mparams values are initialized only once.
  1442 */
  1443 
  1444 #ifndef WIN32
  1445 /* By default use posix locks */
  1446 #include <pthread.h>
  1447 #define MLOCK_T pthread_mutex_t
  1448 #define INITIAL_LOCK(l)      pthread_mutex_init(l, NULL)
  1449 #define ACQUIRE_LOCK(l)      pthread_mutex_lock(l)
  1450 #define RELEASE_LOCK(l)      pthread_mutex_unlock(l)
  1451 
  1452 #if HAVE_MORECORE
  1453 static MLOCK_T morecore_mutex = PTHREAD_MUTEX_INITIALIZER;
  1454 #endif /* HAVE_MORECORE */
  1455 
  1456 static MLOCK_T magic_init_mutex = PTHREAD_MUTEX_INITIALIZER;
  1457 
  1458 #else /* WIN32 */
  1459 /*
  1460    Because lock-protected regions have bounded times, and there
  1461    are no recursive lock calls, we can use simple spinlocks.
  1462 */
  1463 
  1464 #define MLOCK_T long
  1465 static int
  1466 win32_acquire_lock(MLOCK_T * sl)
  1467 {
  1468     for (;;) {
  1469 #ifdef InterlockedCompareExchangePointer
  1470         if (!InterlockedCompareExchange(sl, 1, 0))
  1471             return 0;
  1472 #else /* Use older void* version */
  1473         if (!InterlockedCompareExchange((void **) sl, (void *) 1, (void *) 0))
  1474             return 0;
  1475 #endif /* InterlockedCompareExchangePointer */
  1476         Sleep(0);
  1477     }
  1478 }
  1479 
  1480 static void
  1481 win32_release_lock(MLOCK_T * sl)
  1482 {
  1483     InterlockedExchange(sl, 0);
  1484 }
  1485 
  1486 #define INITIAL_LOCK(l)      *(l)=0
  1487 #define ACQUIRE_LOCK(l)      win32_acquire_lock(l)
  1488 #define RELEASE_LOCK(l)      win32_release_lock(l)
  1489 #if HAVE_MORECORE
  1490 static MLOCK_T morecore_mutex;
  1491 #endif /* HAVE_MORECORE */
  1492 static MLOCK_T magic_init_mutex;
  1493 #endif /* WIN32 */
  1494 
  1495 #define USE_LOCK_BIT               (2U)
  1496 #else /* USE_LOCKS */
  1497 #define USE_LOCK_BIT               (0U)
  1498 #define INITIAL_LOCK(l)
  1499 #endif /* USE_LOCKS */
  1500 
  1501 #if USE_LOCKS && HAVE_MORECORE
  1502 #define ACQUIRE_MORECORE_LOCK()    ACQUIRE_LOCK(&morecore_mutex);
  1503 #define RELEASE_MORECORE_LOCK()    RELEASE_LOCK(&morecore_mutex);
  1504 #else /* USE_LOCKS && HAVE_MORECORE */
  1505 #define ACQUIRE_MORECORE_LOCK()
  1506 #define RELEASE_MORECORE_LOCK()
  1507 #endif /* USE_LOCKS && HAVE_MORECORE */
  1508 
  1509 #if USE_LOCKS
  1510 #define ACQUIRE_MAGIC_INIT_LOCK()  ACQUIRE_LOCK(&magic_init_mutex);
  1511 #define RELEASE_MAGIC_INIT_LOCK()  RELEASE_LOCK(&magic_init_mutex);
  1512 #else /* USE_LOCKS */
  1513 #define ACQUIRE_MAGIC_INIT_LOCK()
  1514 #define RELEASE_MAGIC_INIT_LOCK()
  1515 #endif /* USE_LOCKS */
  1516 
  1517 
  1518 /* -----------------------  Chunk representations ------------------------ */
  1519 
  1520 /*
  1521   (The following includes lightly edited explanations by Colin Plumb.)
  1522 
  1523   The malloc_chunk declaration below is misleading (but accurate and
  1524   necessary).  It declares a "view" into memory allowing access to
  1525   necessary fields at known offsets from a given base.
  1526 
  1527   Chunks of memory are maintained using a `boundary tag' method as
  1528   originally described by Knuth.  (See the paper by Paul Wilson
  1529   ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such
  1530   techniques.)  Sizes of free chunks are stored both in the front of
  1531   each chunk and at the end.  This makes consolidating fragmented
  1532   chunks into bigger chunks fast.  The head fields also hold bits
  1533   representing whether chunks are free or in use.
  1534 
  1535   Here are some pictures to make it clearer.  They are "exploded" to
  1536   show that the state of a chunk can be thought of as extending from
  1537   the high 31 bits of the head field of its header through the
  1538   prev_foot and PINUSE_BIT bit of the following chunk header.
  1539 
  1540   A chunk that's in use looks like:
  1541 
  1542    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1543            | Size of previous chunk (if P = 1)                             |
  1544            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1545          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
  1546          | Size of this chunk                                         1| +-+
  1547    mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1548          |                                                               |
  1549          +-                                                             -+
  1550          |                                                               |
  1551          +-                                                             -+
  1552          |                                                               :
  1553          +-      size - sizeof(size_t) available payload bytes          -+
  1554          :                                                               |
  1555  chunk-> +-                                                             -+
  1556          |                                                               |
  1557          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1558        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|
  1559        | Size of next chunk (may or may not be in use)               | +-+
  1560  mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1561 
  1562     And if it's free, it looks like this:
  1563 
  1564    chunk-> +-                                                             -+
  1565            | User payload (must be in use, or we would have merged!)       |
  1566            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1567          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
  1568          | Size of this chunk                                         0| +-+
  1569    mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1570          | Next pointer                                                  |
  1571          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1572          | Prev pointer                                                  |
  1573          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1574          |                                                               :
  1575          +-      size - sizeof(struct chunk) unused bytes               -+
  1576          :                                                               |
  1577  chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1578          | Size of this chunk                                            |
  1579          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1580        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|
  1581        | Size of next chunk (must be in use, or we would have merged)| +-+
  1582  mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1583        |                                                               :
  1584        +- User payload                                                -+
  1585        :                                                               |
  1586        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1587                                                                      |0|
  1588                                                                      +-+
  1589   Note that since we always merge adjacent free chunks, the chunks
  1590   adjacent to a free chunk must be in use.
  1591 
  1592   Given a pointer to a chunk (which can be derived trivially from the
  1593   payload pointer) we can, in O(1) time, find out whether the adjacent
  1594   chunks are free, and if so, unlink them from the lists that they
  1595   are on and merge them with the current chunk.
  1596 
  1597   Chunks always begin on even word boundaries, so the mem portion
  1598   (which is returned to the user) is also on an even word boundary, and
  1599   thus at least double-word aligned.
  1600 
  1601   The P (PINUSE_BIT) bit, stored in the unused low-order bit of the
  1602   chunk size (which is always a multiple of two words), is an in-use
  1603   bit for the *previous* chunk.  If that bit is *clear*, then the
  1604   word before the current chunk size contains the previous chunk
  1605   size, and can be used to find the front of the previous chunk.
  1606   The very first chunk allocated always has this bit set, preventing
  1607   access to non-existent (or non-owned) memory. If pinuse is set for
  1608   any given chunk, then you CANNOT determine the size of the
  1609   previous chunk, and might even get a memory addressing fault when
  1610   trying to do so.
  1611 
  1612   The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of
  1613   the chunk size redundantly records whether the current chunk is
  1614   inuse. This redundancy enables usage checks within free and realloc,
  1615   and reduces indirection when freeing and consolidating chunks.
  1616 
  1617   Each freshly allocated chunk must have both cinuse and pinuse set.
  1618   That is, each allocated chunk borders either a previously allocated
  1619   and still in-use chunk, or the base of its memory arena. This is
  1620   ensured by making all allocations from the the `lowest' part of any
  1621   found chunk.  Further, no free chunk physically borders another one,
  1622   so each free chunk is known to be preceded and followed by either
  1623   inuse chunks or the ends of memory.
  1624 
  1625   Note that the `foot' of the current chunk is actually represented
  1626   as the prev_foot of the NEXT chunk. This makes it easier to
  1627   deal with alignments etc but can be very confusing when trying
  1628   to extend or adapt this code.
  1629 
  1630   The exceptions to all this are
  1631 
  1632      1. The special chunk `top' is the top-most available chunk (i.e.,
  1633         the one bordering the end of available memory). It is treated
  1634         specially.  Top is never included in any bin, is used only if
  1635         no other chunk is available, and is released back to the
  1636         system if it is very large (see M_TRIM_THRESHOLD).  In effect,
  1637         the top chunk is treated as larger (and thus less well
  1638         fitting) than any other available chunk.  The top chunk
  1639         doesn't update its trailing size field since there is no next
  1640         contiguous chunk that would have to index off it. However,
  1641         space is still allocated for it (TOP_FOOT_SIZE) to enable
  1642         separation or merging when space is extended.
  1643 
  1644      3. Chunks allocated via mmap, which have the lowest-order bit
  1645         (IS_MMAPPED_BIT) set in their prev_foot fields, and do not set
  1646         PINUSE_BIT in their head fields.  Because they are allocated
  1647         one-by-one, each must carry its own prev_foot field, which is
  1648         also used to hold the offset this chunk has within its mmapped
  1649         region, which is needed to preserve alignment. Each mmapped
  1650         chunk is trailed by the first two fields of a fake next-chunk
  1651         for sake of usage checks.
  1652 
  1653 */
  1654 
  1655 struct malloc_chunk
  1656 {
  1657     size_t prev_foot;           /* Size of previous chunk (if free).  */
  1658     size_t head;                /* Size and inuse bits. */
  1659     struct malloc_chunk *fd;    /* double links -- used only if free. */
  1660     struct malloc_chunk *bk;
  1661 };
  1662 
  1663 typedef struct malloc_chunk mchunk;
  1664 typedef struct malloc_chunk *mchunkptr;
  1665 typedef struct malloc_chunk *sbinptr;   /* The type of bins of chunks */
  1666 typedef size_t bindex_t;        /* Described below */
  1667 typedef unsigned int binmap_t;  /* Described below */
  1668 typedef unsigned int flag_t;    /* The type of various bit flag sets */
  1669 
  1670 /* ------------------- Chunks sizes and alignments ----------------------- */
  1671 
  1672 #define MCHUNK_SIZE         (sizeof(mchunk))
  1673 
  1674 #if FOOTERS
  1675 #define CHUNK_OVERHEAD      (TWO_SIZE_T_SIZES)
  1676 #else /* FOOTERS */
  1677 #define CHUNK_OVERHEAD      (SIZE_T_SIZE)
  1678 #endif /* FOOTERS */
  1679 
  1680 /* MMapped chunks need a second word of overhead ... */
  1681 #define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
  1682 /* ... and additional padding for fake next-chunk at foot */
  1683 #define MMAP_FOOT_PAD       (FOUR_SIZE_T_SIZES)
  1684 
  1685 /* The smallest size we can malloc is an aligned minimal chunk */
  1686 #define MIN_CHUNK_SIZE\
  1687   ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
  1688 
  1689 /* conversion from malloc headers to user pointers, and back */
  1690 #define chunk2mem(p)        ((void*)((char*)(p)       + TWO_SIZE_T_SIZES))
  1691 #define mem2chunk(mem)      ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
  1692 /* chunk associated with aligned address A */
  1693 #define align_as_chunk(A)   (mchunkptr)((A) + align_offset(chunk2mem(A)))
  1694 
  1695 /* Bounds on request (not chunk) sizes. */
  1696 #define MAX_REQUEST         ((-MIN_CHUNK_SIZE) << 2)
  1697 #define MIN_REQUEST         (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)
  1698 
  1699 /* pad request bytes into a usable size */
  1700 #define pad_request(req) \
  1701    (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
  1702 
  1703 /* pad request, checking for minimum (but not maximum) */
  1704 #define request2size(req) \
  1705   (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))
  1706 
  1707 
  1708 /* ------------------ Operations on head and foot fields ----------------- */
  1709 
  1710 /*
  1711   The head field of a chunk is or'ed with PINUSE_BIT when previous
  1712   adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in
  1713   use. If the chunk was obtained with mmap, the prev_foot field has
  1714   IS_MMAPPED_BIT set, otherwise holding the offset of the base of the
  1715   mmapped region to the base of the chunk.
  1716 */
  1717 
  1718 #define PINUSE_BIT          (SIZE_T_ONE)
  1719 #define CINUSE_BIT          (SIZE_T_TWO)
  1720 #define INUSE_BITS          (PINUSE_BIT|CINUSE_BIT)
  1721 
  1722 /* Head value for fenceposts */
  1723 #define FENCEPOST_HEAD      (INUSE_BITS|SIZE_T_SIZE)
  1724 
  1725 /* extraction of fields from head words */
  1726 #define cinuse(p)           ((p)->head & CINUSE_BIT)
  1727 #define pinuse(p)           ((p)->head & PINUSE_BIT)
  1728 #define chunksize(p)        ((p)->head & ~(INUSE_BITS))
  1729 
  1730 #define clear_pinuse(p)     ((p)->head &= ~PINUSE_BIT)
  1731 #define clear_cinuse(p)     ((p)->head &= ~CINUSE_BIT)
  1732 
  1733 /* Treat space at ptr +/- offset as a chunk */
  1734 #define chunk_plus_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))
  1735 #define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s)))
  1736 
  1737 /* Ptr to next or previous physical malloc_chunk. */
  1738 #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~INUSE_BITS)))
  1739 #define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) ))
  1740 
  1741 /* extract next chunk's pinuse bit */
  1742 #define next_pinuse(p)  ((next_chunk(p)->head) & PINUSE_BIT)
  1743 
  1744 /* Get/set size at footer */
  1745 #define get_foot(p, s)  (((mchunkptr)((char*)(p) + (s)))->prev_foot)
  1746 #define set_foot(p, s)  (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s))
  1747 
  1748 /* Set size, pinuse bit, and foot */
  1749 #define set_size_and_pinuse_of_free_chunk(p, s)\
  1750   ((p)->head = (s|PINUSE_BIT), set_foot(p, s))
  1751 
  1752 /* Set size, pinuse bit, foot, and clear next pinuse */
  1753 #define set_free_with_pinuse(p, s, n)\
  1754   (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s))
  1755 
  1756 #define is_mmapped(p)\
  1757   (!((p)->head & PINUSE_BIT) && ((p)->prev_foot & IS_MMAPPED_BIT))
  1758 
  1759 /* Get the internal overhead associated with chunk p */
  1760 #define overhead_for(p)\
  1761  (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD)
  1762 
  1763 /* Return true if malloced space is not necessarily cleared */
  1764 #if MMAP_CLEARS
  1765 #define calloc_must_clear(p) (!is_mmapped(p))
  1766 #else /* MMAP_CLEARS */
  1767 #define calloc_must_clear(p) (1)
  1768 #endif /* MMAP_CLEARS */
  1769 
  1770 /* ---------------------- Overlaid data structures ----------------------- */
  1771 
  1772 /*
  1773   When chunks are not in use, they are treated as nodes of either
  1774   lists or trees.
  1775 
  1776   "Small"  chunks are stored in circular doubly-linked lists, and look
  1777   like this:
  1778 
  1779     chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1780             |             Size of previous chunk                            |
  1781             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1782     `head:' |             Size of chunk, in bytes                         |P|
  1783       mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1784             |             Forward pointer to next chunk in list             |
  1785             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1786             |             Back pointer to previous chunk in list            |
  1787             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1788             |             Unused space (may be 0 bytes long)                .
  1789             .                                                               .
  1790             .                                                               |
  1791 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1792     `foot:' |             Size of chunk, in bytes                           |
  1793             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1794 
  1795   Larger chunks are kept in a form of bitwise digital trees (aka
  1796   tries) keyed on chunksizes.  Because malloc_tree_chunks are only for
  1797   free chunks greater than 256 bytes, their size doesn't impose any
  1798   constraints on user chunk sizes.  Each node looks like:
  1799 
  1800     chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1801             |             Size of previous chunk                            |
  1802             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1803     `head:' |             Size of chunk, in bytes                         |P|
  1804       mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1805             |             Forward pointer to next chunk of same size        |
  1806             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1807             |             Back pointer to previous chunk of same size       |
  1808             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1809             |             Pointer to left child (child[0])                  |
  1810             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1811             |             Pointer to right child (child[1])                 |
  1812             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1813             |             Pointer to parent                                 |
  1814             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1815             |             bin index of this chunk                           |
  1816             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1817             |             Unused space                                      .
  1818             .                                                               |
  1819 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1820     `foot:' |             Size of chunk, in bytes                           |
  1821             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  1822 
  1823   Each tree holding treenodes is a tree of unique chunk sizes.  Chunks
  1824   of the same size are arranged in a circularly-linked list, with only
  1825   the oldest chunk (the next to be used, in our FIFO ordering)
  1826   actually in the tree.  (Tree members are distinguished by a non-null
  1827   parent pointer.)  If a chunk with the same size an an existing node
  1828   is inserted, it is linked off the existing node using pointers that
  1829   work in the same way as fd/bk pointers of small chunks.
  1830 
  1831   Each tree contains a power of 2 sized range of chunk sizes (the
  1832   smallest is 0x100 <= x < 0x180), which is is divided in half at each
  1833   tree level, with the chunks in the smaller half of the range (0x100
  1834   <= x < 0x140 for the top nose) in the left subtree and the larger
  1835   half (0x140 <= x < 0x180) in the right subtree.  This is, of course,
  1836   done by inspecting individual bits.
  1837 
  1838   Using these rules, each node's left subtree contains all smaller
  1839   sizes than its right subtree.  However, the node at the root of each
  1840   subtree has no particular ordering relationship to either.  (The
  1841   dividing line between the subtree sizes is based on trie relation.)
  1842   If we remove the last chunk of a given size from the interior of the
  1843   tree, we need to replace it with a leaf node.  The tree ordering
  1844   rules permit a node to be replaced by any leaf below it.
  1845 
  1846   The smallest chunk in a tree (a common operation in a best-fit
  1847   allocator) can be found by walking a path to the leftmost leaf in
  1848   the tree.  Unlike a usual binary tree, where we follow left child
  1849   pointers until we reach a null, here we follow the right child
  1850   pointer any time the left one is null, until we reach a leaf with
  1851   both child pointers null. The smallest chunk in the tree will be
  1852   somewhere along that path.
  1853 
  1854   The worst case number of steps to add, find, or remove a node is
  1855   bounded by the number of bits differentiating chunks within
  1856   bins. Under current bin calculations, this ranges from 6 up to 21
  1857   (for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case
  1858   is of course much better.
  1859 */
  1860 
  1861 struct malloc_tree_chunk
  1862 {
  1863     /* The first four fields must be compatible with malloc_chunk */
  1864     size_t prev_foot;
  1865     size_t head;
  1866     struct malloc_tree_chunk *fd;
  1867     struct malloc_tree_chunk *bk;
  1868 
  1869     struct malloc_tree_chunk *child[2];
  1870     struct malloc_tree_chunk *parent;
  1871     bindex_t index;
  1872 };
  1873 
  1874 typedef struct malloc_tree_chunk tchunk;
  1875 typedef struct malloc_tree_chunk *tchunkptr;
  1876 typedef struct malloc_tree_chunk *tbinptr;      /* The type of bins of trees */
  1877 
  1878 /* A little helper macro for trees */
  1879 #define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1])
  1880 
  1881 /* ----------------------------- Segments -------------------------------- */
  1882 
  1883 /*
  1884   Each malloc space may include non-contiguous segments, held in a
  1885   list headed by an embedded malloc_segment record representing the
  1886   top-most space. Segments also include flags holding properties of
  1887   the space. Large chunks that are directly allocated by mmap are not
  1888   included in this list. They are instead independently created and
  1889   destroyed without otherwise keeping track of them.
  1890 
  1891   Segment management mainly comes into play for spaces allocated by
  1892   MMAP.  Any call to MMAP might or might not return memory that is
  1893   adjacent to an existing segment.  MORECORE normally contiguously
  1894   extends the current space, so this space is almost always adjacent,
  1895   which is simpler and faster to deal with. (This is why MORECORE is
  1896   used preferentially to MMAP when both are available -- see
  1897   sys_alloc.)  When allocating using MMAP, we don't use any of the
  1898   hinting mechanisms (inconsistently) supported in various
  1899   implementations of unix mmap, or distinguish reserving from
  1900   committing memory. Instead, we just ask for space, and exploit
  1901   contiguity when we get it.  It is probably possible to do
  1902   better than this on some systems, but no general scheme seems
  1903   to be significantly better.
  1904 
  1905   Management entails a simpler variant of the consolidation scheme
  1906   used for chunks to reduce fragmentation -- new adjacent memory is
  1907   normally prepended or appended to an existing segment. However,
  1908   there are limitations compared to chunk consolidation that mostly
  1909   reflect the fact that segment processing is relatively infrequent
  1910   (occurring only when getting memory from system) and that we
  1911   don't expect to have huge numbers of segments:
  1912 
  1913   * Segments are not indexed, so traversal requires linear scans.  (It
  1914     would be possible to index these, but is not worth the extra
  1915     overhead and complexity for most programs on most platforms.)
  1916   * New segments are only appended to old ones when holding top-most
  1917     memory; if they cannot be prepended to others, they are held in
  1918     different segments.
  1919 
  1920   Except for the top-most segment of an mstate, each segment record
  1921   is kept at the tail of its segment. Segments are added by pushing
  1922   segment records onto the list headed by &mstate.seg for the
  1923   containing mstate.
  1924 
  1925   Segment flags control allocation/merge/deallocation policies:
  1926   * If EXTERN_BIT set, then we did not allocate this segment,
  1927     and so should not try to deallocate or merge with others.
  1928     (This currently holds only for the initial segment passed
  1929     into create_mspace_with_base.)
  1930   * If IS_MMAPPED_BIT set, the segment may be merged with
  1931     other surrounding mmapped segments and trimmed/de-allocated
  1932     using munmap.
  1933   * If neither bit is set, then the segment was obtained using
  1934     MORECORE so can be merged with surrounding MORECORE'd segments
  1935     and deallocated/trimmed using MORECORE with negative arguments.
  1936 */
  1937 
  1938 struct malloc_segment
  1939 {
  1940     char *base;                 /* base address */
  1941     size_t size;                /* allocated size */
  1942     struct malloc_segment *next;        /* ptr to next segment */
  1943     flag_t sflags;              /* mmap and extern flag */
  1944 };
  1945 
  1946 #define is_mmapped_segment(S)  ((S)->sflags & IS_MMAPPED_BIT)
  1947 #define is_extern_segment(S)   ((S)->sflags & EXTERN_BIT)
  1948 
  1949 typedef struct malloc_segment msegment;
  1950 typedef struct malloc_segment *msegmentptr;
  1951 
  1952 /* ---------------------------- malloc_state ----------------------------- */
  1953 
  1954 /*
  1955    A malloc_state holds all of the bookkeeping for a space.
  1956    The main fields are:
  1957 
  1958   Top
  1959     The topmost chunk of the currently active segment. Its size is
  1960     cached in topsize.  The actual size of topmost space is
  1961     topsize+TOP_FOOT_SIZE, which includes space reserved for adding
  1962     fenceposts and segment records if necessary when getting more
  1963     space from the system.  The size at which to autotrim top is
  1964     cached from mparams in trim_check, except that it is disabled if
  1965     an autotrim fails.
  1966 
  1967   Designated victim (dv)
  1968     This is the preferred chunk for servicing small requests that
  1969     don't have exact fits.  It is normally the chunk split off most
  1970     recently to service another small request.  Its size is cached in
  1971     dvsize. The link fields of this chunk are not maintained since it
  1972     is not kept in a bin.
  1973 
  1974   SmallBins
  1975     An array of bin headers for free chunks.  These bins hold chunks
  1976     with sizes less than MIN_LARGE_SIZE bytes. Each bin contains
  1977     chunks of all the same size, spaced 8 bytes apart.  To simplify
  1978     use in double-linked lists, each bin header acts as a malloc_chunk
  1979     pointing to the real first node, if it exists (else pointing to
  1980     itself).  This avoids special-casing for headers.  But to avoid
  1981     waste, we allocate only the fd/bk pointers of bins, and then use
  1982     repositioning tricks to treat these as the fields of a chunk.
  1983 
  1984   TreeBins
  1985     Treebins are pointers to the roots of trees holding a range of
  1986     sizes. There are 2 equally spaced treebins for each power of two
  1987     from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything
  1988     larger.
  1989 
  1990   Bin maps
  1991     There is one bit map for small bins ("smallmap") and one for
  1992     treebins ("treemap).  Each bin sets its bit when non-empty, and
  1993     clears the bit when empty.  Bit operations are then used to avoid
  1994     bin-by-bin searching -- nearly all "search" is done without ever
  1995     looking at bins that won't be selected.  The bit maps
  1996     conservatively use 32 bits per map word, even if on 64bit system.
  1997     For a good description of some of the bit-based techniques used
  1998     here, see Henry S. Warren Jr's book "Hacker's Delight" (and
  1999     supplement at http://hackersdelight.org/). Many of these are
  2000     intended to reduce the branchiness of paths through malloc etc, as
  2001     well as to reduce the number of memory locations read or written.
  2002 
  2003   Segments
  2004     A list of segments headed by an embedded malloc_segment record
  2005     representing the initial space.
  2006 
  2007   Address check support
  2008     The least_addr field is the least address ever obtained from
  2009     MORECORE or MMAP. Attempted frees and reallocs of any address less
  2010     than this are trapped (unless INSECURE is defined).
  2011 
  2012   Magic tag
  2013     A cross-check field that should always hold same value as mparams.magic.
  2014 
  2015   Flags
  2016     Bits recording whether to use MMAP, locks, or contiguous MORECORE
  2017 
  2018   Statistics
  2019     Each space keeps track of current and maximum system memory
  2020     obtained via MORECORE or MMAP.
  2021 
  2022   Locking
  2023     If USE_LOCKS is defined, the "mutex" lock is acquired and released
  2024     around every public call using this mspace.
  2025 */
  2026 
  2027 /* Bin types, widths and sizes */
  2028 #define NSMALLBINS        (32U)
  2029 #define NTREEBINS         (32U)
  2030 #define SMALLBIN_SHIFT    (3U)
  2031 #define SMALLBIN_WIDTH    (SIZE_T_ONE << SMALLBIN_SHIFT)
  2032 #define TREEBIN_SHIFT     (8U)
  2033 #define MIN_LARGE_SIZE    (SIZE_T_ONE << TREEBIN_SHIFT)
  2034 #define MAX_SMALL_SIZE    (MIN_LARGE_SIZE - SIZE_T_ONE)
  2035 #define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD)
  2036 
  2037 struct malloc_state
  2038 {
  2039     binmap_t smallmap;
  2040     binmap_t treemap;
  2041     size_t dvsize;
  2042     size_t topsize;
  2043     char *least_addr;
  2044     mchunkptr dv;
  2045     mchunkptr top;
  2046     size_t trim_check;
  2047     size_t magic;
  2048     mchunkptr smallbins[(NSMALLBINS + 1) * 2];
  2049     tbinptr treebins[NTREEBINS];
  2050     size_t footprint;
  2051     size_t max_footprint;
  2052     flag_t mflags;
  2053 #if USE_LOCKS
  2054     MLOCK_T mutex;              /* locate lock among fields that rarely change */
  2055 #endif                          /* USE_LOCKS */
  2056     msegment seg;
  2057 };
  2058 
  2059 typedef struct malloc_state *mstate;
  2060 
  2061 /* ------------- Global malloc_state and malloc_params ------------------- */
  2062 
  2063 /*
  2064   malloc_params holds global properties, including those that can be
  2065   dynamically set using mallopt. There is a single instance, mparams,
  2066   initialized in init_mparams.
  2067 */
  2068 
  2069 struct malloc_params
  2070 {
  2071     size_t magic;
  2072     size_t page_size;
  2073     size_t granularity;
  2074     size_t mmap_threshold;
  2075     size_t trim_threshold;
  2076     flag_t default_mflags;
  2077 };
  2078 
  2079 static struct malloc_params mparams;
  2080 
  2081 /* The global malloc_state used for all non-"mspace" calls */
  2082 static struct malloc_state _gm_;
  2083 #define gm                 (&_gm_)
  2084 #define is_global(M)       ((M) == &_gm_)
  2085 #define is_initialized(M)  ((M)->top != 0)
  2086 
  2087 /* -------------------------- system alloc setup ------------------------- */
  2088 
  2089 /* Operations on mflags */
  2090 
  2091 #define use_lock(M)           ((M)->mflags &   USE_LOCK_BIT)
  2092 #define enable_lock(M)        ((M)->mflags |=  USE_LOCK_BIT)
  2093 #define disable_lock(M)       ((M)->mflags &= ~USE_LOCK_BIT)
  2094 
  2095 #define use_mmap(M)           ((M)->mflags &   USE_MMAP_BIT)
  2096 #define enable_mmap(M)        ((M)->mflags |=  USE_MMAP_BIT)
  2097 #define disable_mmap(M)       ((M)->mflags &= ~USE_MMAP_BIT)
  2098 
  2099 #define use_noncontiguous(M)  ((M)->mflags &   USE_NONCONTIGUOUS_BIT)
  2100 #define disable_contiguous(M) ((M)->mflags |=  USE_NONCONTIGUOUS_BIT)
  2101 
  2102 #define set_lock(M,L)\
  2103  ((M)->mflags = (L)?\
  2104   ((M)->mflags | USE_LOCK_BIT) :\
  2105   ((M)->mflags & ~USE_LOCK_BIT))
  2106 
  2107 /* page-align a size */
  2108 #define page_align(S)\
  2109  (((S) + (mparams.page_size)) & ~(mparams.page_size - SIZE_T_ONE))
  2110 
  2111 /* granularity-align a size */
  2112 #define granularity_align(S)\
  2113   (((S) + (mparams.granularity)) & ~(mparams.granularity - SIZE_T_ONE))
  2114 
  2115 #define is_page_aligned(S)\
  2116    (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0)
  2117 #define is_granularity_aligned(S)\
  2118    (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0)
  2119 
  2120 /*  True if segment S holds address A */
  2121 #define segment_holds(S, A)\
  2122   ((char*)(A) >= S->base && (char*)(A) < S->base + S->size)
  2123 
  2124 /* Return segment holding given address */
  2125 static msegmentptr
  2126 segment_holding(mstate m, char *addr)
  2127 {
  2128     msegmentptr sp = &m->seg;
  2129     for (;;) {
  2130         if (addr >= sp->base && addr < sp->base + sp->size)
  2131             return sp;
  2132         if ((sp = sp->next) == 0)
  2133             return 0;
  2134     }
  2135 }
  2136 
  2137 /* Return true if segment contains a segment link */
  2138 static int
  2139 has_segment_link(mstate m, msegmentptr ss)
  2140 {
  2141     msegmentptr sp = &m->seg;
  2142     for (;;) {
  2143         if ((char *) sp >= ss->base && (char *) sp < ss->base + ss->size)
  2144             return 1;
  2145         if ((sp = sp->next) == 0)
  2146             return 0;
  2147     }
  2148 }
  2149 
  2150 #ifndef MORECORE_CANNOT_TRIM
  2151 #define should_trim(M,s)  ((s) > (M)->trim_check)
  2152 #else /* MORECORE_CANNOT_TRIM */
  2153 #define should_trim(M,s)  (0)
  2154 #endif /* MORECORE_CANNOT_TRIM */
  2155 
  2156 /*
  2157   TOP_FOOT_SIZE is padding at the end of a segment, including space
  2158   that may be needed to place segment records and fenceposts when new
  2159   noncontiguous segments are added.
  2160 */
  2161 #define TOP_FOOT_SIZE\
  2162   (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE)
  2163 
  2164 
  2165 /* -------------------------------  Hooks -------------------------------- */
  2166 
  2167 /*
  2168   PREACTION should be defined to return 0 on success, and nonzero on
  2169   failure. If you are not using locking, you can redefine these to do
  2170   anything you like.
  2171 */
  2172 
  2173 #if USE_LOCKS
  2174 
  2175 /* Ensure locks are initialized */
  2176 #define GLOBALLY_INITIALIZE() (mparams.page_size == 0 && init_mparams())
  2177 
  2178 #define PREACTION(M)  ((GLOBALLY_INITIALIZE() || use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0)
  2179 #define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); }
  2180 #else /* USE_LOCKS */
  2181 
  2182 #ifndef PREACTION
  2183 #define PREACTION(M) (0)
  2184 #endif /* PREACTION */
  2185 
  2186 #ifndef POSTACTION
  2187 #define POSTACTION(M)
  2188 #endif /* POSTACTION */
  2189 
  2190 #endif /* USE_LOCKS */
  2191 
  2192 /*
  2193   CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses.
  2194   USAGE_ERROR_ACTION is triggered on detected bad frees and
  2195   reallocs. The argument p is an address that might have triggered the
  2196   fault. It is ignored by the two predefined actions, but might be
  2197   useful in custom actions that try to help diagnose errors.
  2198 */
  2199 
  2200 #if PROCEED_ON_ERROR
  2201 
  2202 /* A count of the number of corruption errors causing resets */
  2203 int malloc_corruption_error_count;
  2204 
  2205 /* default corruption action */
  2206 static void reset_on_error(mstate m);
  2207 
  2208 #define CORRUPTION_ERROR_ACTION(m)  reset_on_error(m)
  2209 #define USAGE_ERROR_ACTION(m, p)
  2210 
  2211 #else /* PROCEED_ON_ERROR */
  2212 
  2213 #ifndef CORRUPTION_ERROR_ACTION
  2214 #define CORRUPTION_ERROR_ACTION(m) ABORT
  2215 #endif /* CORRUPTION_ERROR_ACTION */
  2216 
  2217 #ifndef USAGE_ERROR_ACTION
  2218 #define USAGE_ERROR_ACTION(m,p) ABORT
  2219 #endif /* USAGE_ERROR_ACTION */
  2220 
  2221 #endif /* PROCEED_ON_ERROR */
  2222 
  2223 /* -------------------------- Debugging setup ---------------------------- */
  2224 
  2225 #if ! DEBUG
  2226 
  2227 #define check_free_chunk(M,P)
  2228 #define check_inuse_chunk(M,P)
  2229 #define check_malloced_chunk(M,P,N)
  2230 #define check_mmapped_chunk(M,P)
  2231 #define check_malloc_state(M)
  2232 #define check_top_chunk(M,P)
  2233 
  2234 #else /* DEBUG */
  2235 #define check_free_chunk(M,P)       do_check_free_chunk(M,P)
  2236 #define check_inuse_chunk(M,P)      do_check_inuse_chunk(M,P)
  2237 #define check_top_chunk(M,P)        do_check_top_chunk(M,P)
  2238 #define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N)
  2239 #define check_mmapped_chunk(M,P)    do_check_mmapped_chunk(M,P)
  2240 #define check_malloc_state(M)       do_check_malloc_state(M)
  2241 
  2242 static void do_check_any_chunk(mstate m, mchunkptr p);
  2243 static void do_check_top_chunk(mstate m, mchunkptr p);
  2244 static void do_check_mmapped_chunk(mstate m, mchunkptr p);
  2245 static void do_check_inuse_chunk(mstate m, mchunkptr p);
  2246 static void do_check_free_chunk(mstate m, mchunkptr p);
  2247 static void do_check_malloced_chunk(mstate m, void *mem, size_t s);
  2248 static void do_check_tree(mstate m, tchunkptr t);
  2249 static void do_check_treebin(mstate m, bindex_t i);
  2250 static void do_check_smallbin(mstate m, bindex_t i);
  2251 static void do_check_malloc_state(mstate m);
  2252 static int bin_find(mstate m, mchunkptr x);
  2253 static size_t traverse_and_check(mstate m);
  2254 #endif /* DEBUG */
  2255 
  2256 /* ---------------------------- Indexing Bins ---------------------------- */
  2257 
  2258 #define is_small(s)         (((s) >> SMALLBIN_SHIFT) < NSMALLBINS)
  2259 #define small_index(s)      ((s)  >> SMALLBIN_SHIFT)
  2260 #define small_index2size(i) ((i)  << SMALLBIN_SHIFT)
  2261 #define MIN_SMALL_INDEX     (small_index(MIN_CHUNK_SIZE))
  2262 
  2263 /* addressing by index. See above about smallbin repositioning */
  2264 #define smallbin_at(M, i)   ((sbinptr)((char*)&((M)->smallbins[(i)<<1])))
  2265 #define treebin_at(M,i)     (&((M)->treebins[i]))
  2266 
  2267 /* assign tree index for size S to variable I */
  2268 #if defined(__GNUC__) && defined(i386)
  2269 #define compute_tree_index(S, I)\
  2270 {\
  2271   size_t X = S >> TREEBIN_SHIFT;\
  2272   if (X == 0)\
  2273     I = 0;\
  2274   else if (X > 0xFFFF)\
  2275     I = NTREEBINS-1;\
  2276   else {\
  2277     unsigned int K;\
  2278     __asm__("bsrl %1,%0\n\t" : "=r" (K) : "rm"  (X));\
  2279     I =  (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
  2280   }\
  2281 }
  2282 #else /* GNUC */
  2283 #define compute_tree_index(S, I)\
  2284 {\
  2285   size_t X = S >> TREEBIN_SHIFT;\
  2286   if (X == 0)\
  2287     I = 0;\
  2288   else if (X > 0xFFFF)\
  2289     I = NTREEBINS-1;\
  2290   else {\
  2291     unsigned int Y = (unsigned int)X;\
  2292     unsigned int N = ((Y - 0x100) >> 16) & 8;\
  2293     unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\
  2294     N += K;\
  2295     N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\
  2296     K = 14 - N + ((Y <<= K) >> 15);\
  2297     I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\
  2298   }\
  2299 }
  2300 #endif /* GNUC */
  2301 
  2302 /* Bit representing maximum resolved size in a treebin at i */
  2303 #define bit_for_tree_index(i) \
  2304    (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2)
  2305 
  2306 /* Shift placing maximum resolved bit in a treebin at i as sign bit */
  2307 #define leftshift_for_tree_index(i) \
  2308    ((i == NTREEBINS-1)? 0 : \
  2309     ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2)))
  2310 
  2311 /* The size of the smallest chunk held in bin with index i */
  2312 #define minsize_for_tree_index(i) \
  2313    ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) |  \
  2314    (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1)))
  2315 
  2316 
  2317 /* ------------------------ Operations on bin maps ----------------------- */
  2318 
  2319 /* bit corresponding to given index */
  2320 #define idx2bit(i)              ((binmap_t)(1) << (i))
  2321 
  2322 /* Mark/Clear bits with given index */
  2323 #define mark_smallmap(M,i)      ((M)->smallmap |=  idx2bit(i))
  2324 #define clear_smallmap(M,i)     ((M)->smallmap &= ~idx2bit(i))
  2325 #define smallmap_is_marked(M,i) ((M)->smallmap &   idx2bit(i))
  2326 
  2327 #define mark_treemap(M,i)       ((M)->treemap  |=  idx2bit(i))
  2328 #define clear_treemap(M,i)      ((M)->treemap  &= ~idx2bit(i))
  2329 #define treemap_is_marked(M,i)  ((M)->treemap  &   idx2bit(i))
  2330 
  2331 /* index corresponding to given bit */
  2332 
  2333 #if defined(__GNUC__) && defined(i386)
  2334 #define compute_bit2idx(X, I)\
  2335 {\
  2336   unsigned int J;\
  2337   __asm__("bsfl %1,%0\n\t" : "=r" (J) : "rm" (X));\
  2338   I = (bindex_t)J;\
  2339 }
  2340 
  2341 #else /* GNUC */
  2342 #if  USE_BUILTIN_FFS
  2343 #define compute_bit2idx(X, I) I = ffs(X)-1
  2344 
  2345 #else /* USE_BUILTIN_FFS */
  2346 #define compute_bit2idx(X, I)\
  2347 {\
  2348   unsigned int Y = X - 1;\
  2349   unsigned int K = Y >> (16-4) & 16;\
  2350   unsigned int N = K;        Y >>= K;\
  2351   N += K = Y >> (8-3) &  8;  Y >>= K;\
  2352   N += K = Y >> (4-2) &  4;  Y >>= K;\
  2353   N += K = Y >> (2-1) &  2;  Y >>= K;\
  2354   N += K = Y >> (1-0) &  1;  Y >>= K;\
  2355   I = (bindex_t)(N + Y);\
  2356 }
  2357 #endif /* USE_BUILTIN_FFS */
  2358 #endif /* GNUC */
  2359 
  2360 /* isolate the least set bit of a bitmap */
  2361 #define least_bit(x)         ((x) & -(x))
  2362 
  2363 /* mask with all bits to left of least bit of x on */
  2364 #define left_bits(x)         ((x<<1) | -(x<<1))
  2365 
  2366 /* mask with all bits to left of or equal to least bit of x on */
  2367 #define same_or_left_bits(x) ((x) | -(x))
  2368 
  2369 
  2370 /* ----------------------- Runtime Check Support ------------------------- */
  2371 
  2372 /*
  2373   For security, the main invariant is that malloc/free/etc never
  2374   writes to a static address other than malloc_state, unless static
  2375   malloc_state itself has been corrupted, which cannot occur via
  2376   malloc (because of these checks). In essence this means that we
  2377   believe all pointers, sizes, maps etc held in malloc_state, but
  2378   check all of those linked or offsetted from other embedded data
  2379   structures.  These checks are interspersed with main code in a way
  2380   that tends to minimize their run-time cost.
  2381 
  2382   When FOOTERS is defined, in addition to range checking, we also
  2383   verify footer fields of inuse chunks, which can be used guarantee
  2384   that the mstate controlling malloc/free is intact.  This is a
  2385   streamlined version of the approach described by William Robertson
  2386   et al in "Run-time Detection of Heap-based Overflows" LISA'03
  2387   http://www.usenix.org/events/lisa03/tech/robertson.html The footer
  2388   of an inuse chunk holds the xor of its mstate and a random seed,
  2389   that is checked upon calls to free() and realloc().  This is
  2390   (probablistically) unguessable from outside the program, but can be
  2391   computed by any code successfully malloc'ing any chunk, so does not
  2392   itself provide protection against code that has already broken
  2393   security through some other means.  Unlike Robertson et al, we
  2394   always dynamically check addresses of all offset chunks (previous,
  2395   next, etc). This turns out to be cheaper than relying on hashes.
  2396 */
  2397 
  2398 #if !INSECURE
  2399 /* Check if address a is at least as high as any from MORECORE or MMAP */
  2400 #define ok_address(M, a) ((char*)(a) >= (M)->least_addr)
  2401 /* Check if address of next chunk n is higher than base chunk p */
  2402 #define ok_next(p, n)    ((char*)(p) < (char*)(n))
  2403 /* Check if p has its cinuse bit on */
  2404 #define ok_cinuse(p)     cinuse(p)
  2405 /* Check if p has its pinuse bit on */
  2406 #define ok_pinuse(p)     pinuse(p)
  2407 
  2408 #else /* !INSECURE */
  2409 #define ok_address(M, a) (1)
  2410 #define ok_next(b, n)    (1)
  2411 #define ok_cinuse(p)     (1)
  2412 #define ok_pinuse(p)     (1)
  2413 #endif /* !INSECURE */
  2414 
  2415 #if (FOOTERS && !INSECURE)
  2416 /* Check if (alleged) mstate m has expected magic field */
  2417 #define ok_magic(M)      ((M)->magic == mparams.magic)
  2418 #else /* (FOOTERS && !INSECURE) */
  2419 #define ok_magic(M)      (1)
  2420 #endif /* (FOOTERS && !INSECURE) */
  2421 
  2422 
  2423 /* In gcc, use __builtin_expect to minimize impact of checks */
  2424 #if !INSECURE
  2425 #if defined(__GNUC__) && __GNUC__ >= 3
  2426 #define RTCHECK(e)  __builtin_expect(e, 1)
  2427 #else /* GNUC */
  2428 #define RTCHECK(e)  (e)
  2429 #endif /* GNUC */
  2430 #else /* !INSECURE */
  2431 #define RTCHECK(e)  (1)
  2432 #endif /* !INSECURE */
  2433 
  2434 /* macros to set up inuse chunks with or without footers */
  2435 
  2436 #if !FOOTERS
  2437 
  2438 #define mark_inuse_foot(M,p,s)
  2439 
  2440 /* Set cinuse bit and pinuse bit of next chunk */
  2441 #define set_inuse(M,p,s)\
  2442   ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
  2443   ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
  2444 
  2445 /* Set cinuse and pinuse of this chunk and pinuse of next chunk */
  2446 #define set_inuse_and_pinuse(M,p,s)\
  2447   ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
  2448   ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
  2449 
  2450 /* Set size, cinuse and pinuse bit of this chunk */
  2451 #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
  2452   ((p)->head = (s|PINUSE_BIT|CINUSE_BIT))
  2453 
  2454 #else /* FOOTERS */
  2455 
  2456 /* Set foot of inuse chunk to be xor of mstate and seed */
  2457 #define mark_inuse_foot(M,p,s)\
  2458   (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic))
  2459 
  2460 #define get_mstate_for(p)\
  2461   ((mstate)(((mchunkptr)((char*)(p) +\
  2462     (chunksize(p))))->prev_foot ^ mparams.magic))
  2463 
  2464 #define set_inuse(M,p,s)\
  2465   ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
  2466   (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \
  2467   mark_inuse_foot(M,p,s))
  2468 
  2469 #define set_inuse_and_pinuse(M,p,s)\
  2470   ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
  2471   (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\
  2472  mark_inuse_foot(M,p,s))
  2473 
  2474 #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
  2475   ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
  2476   mark_inuse_foot(M, p, s))
  2477 
  2478 #endif /* !FOOTERS */
  2479 
  2480 /* ---------------------------- setting mparams -------------------------- */
  2481 
  2482 /* Initialize mparams */
  2483 static int
  2484 init_mparams(void)
  2485 {
  2486     if (mparams.page_size == 0) {
  2487         size_t s;
  2488 
  2489         mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD;
  2490         mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD;
  2491 #if MORECORE_CONTIGUOUS
  2492         mparams.default_mflags = USE_LOCK_BIT | USE_MMAP_BIT;
  2493 #else /* MORECORE_CONTIGUOUS */
  2494         mparams.default_mflags =
  2495             USE_LOCK_BIT | USE_MMAP_BIT | USE_NONCONTIGUOUS_BIT;
  2496 #endif /* MORECORE_CONTIGUOUS */
  2497 
  2498 #if (FOOTERS && !INSECURE)
  2499         {
  2500 #if USE_DEV_RANDOM
  2501             int fd;
  2502             unsigned char buf[sizeof(size_t)];
  2503             /* Try to use /dev/urandom, else fall back on using time */
  2504             if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 &&
  2505                 read(fd, buf, sizeof(buf)) == sizeof(buf)) {
  2506                 s = *((size_t *) buf);
  2507                 close(fd);
  2508             } else
  2509 #endif /* USE_DEV_RANDOM */
  2510                 s = (size_t) (time(0) ^ (size_t) 0x55555555U);
  2511 
  2512             s |= (size_t) 8U;   /* ensure nonzero */
  2513             s &= ~(size_t) 7U;  /* improve chances of fault for bad values */
  2514 
  2515         }
  2516 #else /* (FOOTERS && !INSECURE) */
  2517         s = (size_t) 0x58585858U;
  2518 #endif /* (FOOTERS && !INSECURE) */
  2519         ACQUIRE_MAGIC_INIT_LOCK();
  2520         if (mparams.magic == 0) {
  2521             mparams.magic = s;
  2522             /* Set up lock for main malloc area */
  2523             INITIAL_LOCK(&gm->mutex);
  2524             gm->mflags = mparams.default_mflags;
  2525         }
  2526         RELEASE_MAGIC_INIT_LOCK();
  2527 
  2528 #ifndef WIN32
  2529         mparams.page_size = malloc_getpagesize;
  2530         mparams.granularity = ((DEFAULT_GRANULARITY != 0) ?
  2531                                DEFAULT_GRANULARITY : mparams.page_size);
  2532 #else /* WIN32 */
  2533         {
  2534             SYSTEM_INFO system_info;
  2535             GetSystemInfo(&system_info);
  2536             mparams.page_size = system_info.dwPageSize;
  2537             mparams.granularity = system_info.dwAllocationGranularity;
  2538         }
  2539 #endif /* WIN32 */
  2540 
  2541         /* Sanity-check configuration:
  2542            size_t must be unsigned and as wide as pointer type.
  2543            ints must be at least 4 bytes.
  2544            alignment must be at least 8.
  2545            Alignment, min chunk size, and page size must all be powers of 2.
  2546          */
  2547         if ((sizeof(size_t) != sizeof(char *)) ||
  2548             (MAX_SIZE_T < MIN_CHUNK_SIZE) ||
  2549             (sizeof(int) < 4) ||
  2550             (MALLOC_ALIGNMENT < (size_t) 8U) ||
  2551             ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT - SIZE_T_ONE)) != 0) ||
  2552             ((MCHUNK_SIZE & (MCHUNK_SIZE - SIZE_T_ONE)) != 0) ||
  2553             ((mparams.granularity & (mparams.granularity - SIZE_T_ONE)) != 0)
  2554             || ((mparams.page_size & (mparams.page_size - SIZE_T_ONE)) != 0))
  2555             ABORT;
  2556     }
  2557     return 0;
  2558 }
  2559 
  2560 /* support for mallopt */
  2561 static int
  2562 change_mparam(int param_number, int value)
  2563 {
  2564     size_t val = (size_t) value;
  2565     init_mparams();
  2566     switch (param_number) {
  2567     case M_TRIM_THRESHOLD:
  2568         mparams.trim_threshold = val;
  2569         return 1;
  2570     case M_GRANULARITY:
  2571         if (val >= mparams.page_size && ((val & (val - 1)) == 0)) {
  2572             mparams.granularity = val;
  2573             return 1;
  2574         } else
  2575             return 0;
  2576     case M_MMAP_THRESHOLD:
  2577         mparams.mmap_threshold = val;
  2578         return 1;
  2579     default:
  2580         return 0;
  2581     }
  2582 }
  2583 
  2584 #if DEBUG
  2585 /* ------------------------- Debugging Support --------------------------- */
  2586 
  2587 /* Check properties of any chunk, whether free, inuse, mmapped etc  */
  2588 static void
  2589 do_check_any_chunk(mstate m, mchunkptr p)
  2590 {
  2591     assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
  2592     assert(ok_address(m, p));
  2593 }
  2594 
  2595 /* Check properties of top chunk */
  2596 static void
  2597 do_check_top_chunk(mstate m, mchunkptr p)
  2598 {
  2599     msegmentptr sp = segment_holding(m, (char *) p);
  2600     size_t sz = chunksize(p);
  2601     assert(sp != 0);
  2602     assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
  2603     assert(ok_address(m, p));
  2604     assert(sz == m->topsize);
  2605     assert(sz > 0);
  2606     assert(sz == ((sp->base + sp->size) - (char *) p) - TOP_FOOT_SIZE);
  2607     assert(pinuse(p));
  2608     assert(!next_pinuse(p));
  2609 }
  2610 
  2611 /* Check properties of (inuse) mmapped chunks */
  2612 static void
  2613 do_check_mmapped_chunk(mstate m, mchunkptr p)
  2614 {
  2615     size_t sz = chunksize(p);
  2616     size_t len = (sz + (p->prev_foot & ~IS_MMAPPED_BIT) + MMAP_FOOT_PAD);
  2617     assert(is_mmapped(p));
  2618     assert(use_mmap(m));
  2619     assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
  2620     assert(ok_address(m, p));
  2621     assert(!is_small(sz));
  2622     assert((len & (mparams.page_size - SIZE_T_ONE)) == 0);
  2623     assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD);
  2624     assert(chunk_plus_offset(p, sz + SIZE_T_SIZE)->head == 0);
  2625 }
  2626 
  2627 /* Check properties of inuse chunks */
  2628 static void
  2629 do_check_inuse_chunk(mstate m, mchunkptr p)
  2630 {
  2631     do_check_any_chunk(m, p);
  2632     assert(cinuse(p));
  2633     assert(next_pinuse(p));
  2634     /* If not pinuse and not mmapped, previous chunk has OK offset */
  2635     assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p);
  2636     if (is_mmapped(p))
  2637         do_check_mmapped_chunk(m, p);
  2638 }
  2639 
  2640 /* Check properties of free chunks */
  2641 static void
  2642 do_check_free_chunk(mstate m, mchunkptr p)
  2643 {
  2644     size_t sz = p->head & ~(PINUSE_BIT | CINUSE_BIT);
  2645     mchunkptr next = chunk_plus_offset(p, sz);
  2646     do_check_any_chunk(m, p);
  2647     assert(!cinuse(p));
  2648     assert(!next_pinuse(p));
  2649     assert(!is_mmapped(p));
  2650     if (p != m->dv && p != m->top) {
  2651         if (sz >= MIN_CHUNK_SIZE) {
  2652             assert((sz & CHUNK_ALIGN_MASK) == 0);
  2653             assert(is_aligned(chunk2mem(p)));
  2654             assert(next->prev_foot == sz);
  2655             assert(pinuse(p));
  2656             assert(next == m->top || cinuse(next));
  2657             assert(p->fd->bk == p);
  2658             assert(p->bk->fd == p);
  2659         } else                  /* markers are always of size SIZE_T_SIZE */
  2660             assert(sz == SIZE_T_SIZE);
  2661     }
  2662 }
  2663 
  2664 /* Check properties of malloced chunks at the point they are malloced */
  2665 static void
  2666 do_check_malloced_chunk(mstate m, void *mem, size_t s)
  2667 {
  2668     if (mem != 0) {
  2669         mchunkptr p = mem2chunk(mem);
  2670         size_t sz = p->head & ~(PINUSE_BIT | CINUSE_BIT);
  2671         do_check_inuse_chunk(m, p);
  2672         assert((sz & CHUNK_ALIGN_MASK) == 0);
  2673         assert(sz >= MIN_CHUNK_SIZE);
  2674         assert(sz >= s);
  2675         /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */
  2676         assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE));
  2677     }
  2678 }
  2679 
  2680 /* Check a tree and its subtrees.  */
  2681 static void
  2682 do_check_tree(mstate m, tchunkptr t)
  2683 {
  2684     tchunkptr head = 0;
  2685     tchunkptr u = t;
  2686     bindex_t tindex = t->index;
  2687     size_t tsize = chunksize(t);
  2688     bindex_t idx;
  2689     compute_tree_index(tsize, idx);
  2690     assert(tindex == idx);
  2691     assert(tsize >= MIN_LARGE_SIZE);
  2692     assert(tsize >= minsize_for_tree_index(idx));
  2693     assert((idx == NTREEBINS - 1)
  2694            || (tsize < minsize_for_tree_index((idx + 1))));
  2695 
  2696     do {                        /* traverse through chain of same-sized nodes */
  2697         do_check_any_chunk(m, ((mchunkptr) u));
  2698         assert(u->index == tindex);
  2699         assert(chunksize(u) == tsize);
  2700         assert(!cinuse(u));
  2701         assert(!next_pinuse(u));
  2702         assert(u->fd->bk == u);
  2703         assert(u->bk->fd == u);
  2704         if (u->parent == 0) {
  2705             assert(u->child[0] == 0);
  2706             assert(u->child[1] == 0);
  2707         } else {
  2708             assert(head == 0);  /* only one node on chain has parent */
  2709             head = u;
  2710             assert(u->parent != u);
  2711             assert(u->parent->child[0] == u ||
  2712                    u->parent->child[1] == u ||
  2713                    *((tbinptr *) (u->parent)) == u);
  2714             if (u->child[0] != 0) {
  2715                 assert(u->child[0]->parent == u);
  2716                 assert(u->child[0] != u);
  2717                 do_check_tree(m, u->child[0]);
  2718             }
  2719             if (u->child[1] != 0) {
  2720                 assert(u->child[1]->parent == u);
  2721                 assert(u->child[1] != u);
  2722                 do_check_tree(m, u->child[1]);
  2723             }
  2724             if (u->child[0] != 0 && u->child[1] != 0) {
  2725                 assert(chunksize(u->child[0]) < chunksize(u->child[1]));
  2726             }
  2727         }
  2728         u = u->fd;
  2729     }
  2730     while (u != t);
  2731     assert(head != 0);
  2732 }
  2733 
  2734 /*  Check all the chunks in a treebin.  */
  2735 static void
  2736 do_check_treebin(mstate m, bindex_t i)
  2737 {
  2738     tbinptr *tb = treebin_at(m, i);
  2739     tchunkptr t = *tb;
  2740     int empty = (m->treemap & (1U << i)) == 0;
  2741     if (t == 0)
  2742         assert(empty);
  2743     if (!empty)
  2744         do_check_tree(m, t);
  2745 }
  2746 
  2747 /*  Check all the chunks in a smallbin.  */
  2748 static void
  2749 do_check_smallbin(mstate m, bindex_t i)
  2750 {
  2751     sbinptr b = smallbin_at(m, i);
  2752     mchunkptr p = b->bk;
  2753     unsigned int empty = (m->smallmap & (1U << i)) == 0;
  2754     if (p == b)
  2755         assert(empty);
  2756     if (!empty) {
  2757         for (; p != b; p = p->bk) {
  2758             size_t size = chunksize(p);
  2759             mchunkptr q;
  2760             /* each chunk claims to be free */
  2761             do_check_free_chunk(m, p);
  2762             /* chunk belongs in bin */
  2763             assert(small_index(size) == i);
  2764             assert(p->bk == b || chunksize(p->bk) == chunksize(p));
  2765             /* chunk is followed by an inuse chunk */
  2766             q = next_chunk(p);
  2767             if (q->head != FENCEPOST_HEAD)
  2768                 do_check_inuse_chunk(m, q);
  2769         }
  2770     }
  2771 }
  2772 
  2773 /* Find x in a bin. Used in other check functions. */
  2774 static int
  2775 bin_find(mstate m, mchunkptr x)
  2776 {
  2777     size_t size = chunksize(x);
  2778     if (is_small(size)) {
  2779         bindex_t sidx = small_index(size);
  2780         sbinptr b = smallbin_at(m, sidx);
  2781         if (smallmap_is_marked(m, sidx)) {
  2782             mchunkptr p = b;
  2783             do {
  2784                 if (p == x)
  2785                     return 1;
  2786             }
  2787             while ((p = p->fd) != b);
  2788         }
  2789     } else {
  2790         bindex_t tidx;
  2791         compute_tree_index(size, tidx);
  2792         if (treemap_is_marked(m, tidx)) {
  2793             tchunkptr t = *treebin_at(m, tidx);
  2794             size_t sizebits = size << leftshift_for_tree_index(tidx);
  2795             while (t != 0 && chunksize(t) != size) {
  2796                 t = t->child[(sizebits >> (SIZE_T_BITSIZE - SIZE_T_ONE)) & 1];
  2797                 sizebits <<= 1;
  2798             }
  2799             if (t != 0) {
  2800                 tchunkptr u = t;
  2801                 do {
  2802                     if (u == (tchunkptr) x)
  2803                         return 1;
  2804                 }
  2805                 while ((u = u->fd) != t);
  2806             }
  2807         }
  2808     }
  2809     return 0;
  2810 }
  2811 
  2812 /* Traverse each chunk and check it; return total */
  2813 static size_t
  2814 traverse_and_check(mstate m)
  2815 {
  2816     size_t sum = 0;
  2817     if (is_initialized(m)) {
  2818         msegmentptr s = &m->seg;
  2819         sum += m->topsize + TOP_FOOT_SIZE;
  2820         while (s != 0) {
  2821             mchunkptr q = align_as_chunk(s->base);
  2822             mchunkptr lastq = 0;
  2823             assert(pinuse(q));
  2824             while (segment_holds(s, q) &&
  2825                    q != m->top && q->head != FENCEPOST_HEAD) {
  2826                 sum += chunksize(q);
  2827                 if (cinuse(q)) {
  2828                     assert(!bin_find(m, q));
  2829                     do_check_inuse_chunk(m, q);
  2830                 } else {
  2831                     assert(q == m->dv || bin_find(m, q));
  2832                     assert(lastq == 0 || cinuse(lastq));        /* Not 2 consecutive free */
  2833                     do_check_free_chunk(m, q);
  2834                 }
  2835                 lastq = q;
  2836                 q = next_chunk(q);
  2837             }
  2838             s = s->next;
  2839         }
  2840     }
  2841     return sum;
  2842 }
  2843 
  2844 /* Check all properties of malloc_state. */
  2845 static void
  2846 do_check_malloc_state(mstate m)
  2847 {
  2848     bindex_t i;
  2849     size_t total;
  2850     /* check bins */
  2851     for (i = 0; i < NSMALLBINS; ++i)
  2852         do_check_smallbin(m, i);
  2853     for (i = 0; i < NTREEBINS; ++i)
  2854         do_check_treebin(m, i);
  2855 
  2856     if (m->dvsize != 0) {       /* check dv chunk */
  2857         do_check_any_chunk(m, m->dv);
  2858         assert(m->dvsize == chunksize(m->dv));
  2859         assert(m->dvsize >= MIN_CHUNK_SIZE);
  2860         assert(bin_find(m, m->dv) == 0);
  2861     }
  2862 
  2863     if (m->top != 0) {          /* check top chunk */
  2864         do_check_top_chunk(m, m->top);
  2865         assert(m->topsize == chunksize(m->top));
  2866         assert(m->topsize > 0);
  2867         assert(bin_find(m, m->top) == 0);
  2868     }
  2869 
  2870     total = traverse_and_check(m);
  2871     assert(total <= m->footprint);
  2872     assert(m->footprint <= m->max_footprint);
  2873 }
  2874 #endif /* DEBUG */
  2875 
  2876 /* ----------------------------- statistics ------------------------------ */
  2877 
  2878 #if !NO_MALLINFO
  2879 static struct mallinfo
  2880 internal_mallinfo(mstate m)
  2881 {
  2882     struct mallinfo nm = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
  2883     if (!PREACTION(m)) {
  2884         check_malloc_state(m);
  2885         if (is_initialized(m)) {
  2886             size_t nfree = SIZE_T_ONE;  /* top always free */
  2887             size_t mfree = m->topsize + TOP_FOOT_SIZE;
  2888             size_t sum = mfree;
  2889             msegmentptr s = &m->seg;
  2890             while (s != 0) {
  2891                 mchunkptr q = align_as_chunk(s->base);
  2892                 while (segment_holds(s, q) &&
  2893                        q != m->top && q->head != FENCEPOST_HEAD) {
  2894                     size_t sz = chunksize(q);
  2895                     sum += sz;
  2896                     if (!cinuse(q)) {
  2897                         mfree += sz;
  2898                         ++nfree;
  2899                     }
  2900                     q = next_chunk(q);
  2901                 }
  2902                 s = s->next;
  2903             }
  2904 
  2905             nm.arena = sum;
  2906             nm.ordblks = nfree;
  2907             nm.hblkhd = m->footprint - sum;
  2908             nm.usmblks = m->max_footprint;
  2909             nm.uordblks = m->footprint - mfree;
  2910             nm.fordblks = mfree;
  2911             nm.keepcost = m->topsize;
  2912         }
  2913 
  2914         POSTACTION(m);
  2915     }
  2916     return nm;
  2917 }
  2918 #endif /* !NO_MALLINFO */
  2919 
  2920 static void
  2921 internal_malloc_stats(mstate m)
  2922 {
  2923     if (!PREACTION(m)) {
  2924         size_t maxfp = 0;
  2925         size_t fp = 0;
  2926         size_t used = 0;
  2927         check_malloc_state(m);
  2928         if (is_initialized(m)) {
  2929             msegmentptr s = &m->seg;
  2930             maxfp = m->max_footprint;
  2931             fp = m->footprint;
  2932             used = fp - (m->topsize + TOP_FOOT_SIZE);
  2933 
  2934             while (s != 0) {
  2935                 mchunkptr q = align_as_chunk(s->base);
  2936                 while (segment_holds(s, q) &&
  2937                        q != m->top && q->head != FENCEPOST_HEAD) {
  2938                     if (!cinuse(q))
  2939                         used -= chunksize(q);
  2940                     q = next_chunk(q);
  2941                 }
  2942                 s = s->next;
  2943             }
  2944         }
  2945 #ifndef LACKS_STDIO_H
  2946         fprintf(stderr, "max system bytes = %10lu\n",
  2947                 (unsigned long) (maxfp));
  2948         fprintf(stderr, "system bytes     = %10lu\n", (unsigned long) (fp));
  2949         fprintf(stderr, "in use bytes     = %10lu\n", (unsigned long) (used));
  2950 #endif
  2951 
  2952         POSTACTION(m);
  2953     }
  2954 }
  2955 
  2956 /* ----------------------- Operations on smallbins ----------------------- */
  2957 
  2958 /*
  2959   Various forms of linking and unlinking are defined as macros.  Even
  2960   the ones for trees, which are very long but have very short typical
  2961   paths.  This is ugly but reduces reliance on inlining support of
  2962   compilers.
  2963 */
  2964 
  2965 /* Link a free chunk into a smallbin  */
  2966 #define insert_small_chunk(M, P, S) {\
  2967   bindex_t I  = small_index(S);\
  2968   mchunkptr B = smallbin_at(M, I);\
  2969   mchunkptr F = B;\
  2970   assert(S >= MIN_CHUNK_SIZE);\
  2971   if (!smallmap_is_marked(M, I))\
  2972     mark_smallmap(M, I);\
  2973   else if (RTCHECK(ok_address(M, B->fd)))\
  2974     F = B->fd;\
  2975   else {\
  2976     CORRUPTION_ERROR_ACTION(M);\
  2977   }\
  2978   B->fd = P;\
  2979   F->bk = P;\
  2980   P->fd = F;\
  2981   P->bk = B;\
  2982 }
  2983 
  2984 /* Unlink a chunk from a smallbin  */
  2985 #define unlink_small_chunk(M, P, S) {\
  2986   mchunkptr F = P->fd;\
  2987   mchunkptr B = P->bk;\
  2988   bindex_t I = small_index(S);\
  2989   assert(P != B);\
  2990   assert(P != F);\
  2991   assert(chunksize(P) == small_index2size(I));\
  2992   if (F == B)\
  2993     clear_smallmap(M, I);\
  2994   else if (RTCHECK((F == smallbin_at(M,I) || ok_address(M, F)) &&\
  2995                    (B == smallbin_at(M,I) || ok_address(M, B)))) {\
  2996     F->bk = B;\
  2997     B->fd = F;\
  2998   }\
  2999   else {\
  3000     CORRUPTION_ERROR_ACTION(M);\
  3001   }\
  3002 }
  3003 
  3004 /* Unlink the first chunk from a smallbin */
  3005 #define unlink_first_small_chunk(M, B, P, I) {\
  3006   mchunkptr F = P->fd;\
  3007   assert(P != B);\
  3008   assert(P != F);\
  3009   assert(chunksize(P) == small_index2size(I));\
  3010   if (B == F)\
  3011     clear_smallmap(M, I);\
  3012   else if (RTCHECK(ok_address(M, F))) {\
  3013     B->fd = F;\
  3014     F->bk = B;\
  3015   }\
  3016   else {\
  3017     CORRUPTION_ERROR_ACTION(M);\
  3018   }\
  3019 }
  3020 
  3021 /* Replace dv node, binning the old one */
  3022 /* Used only when dvsize known to be small */
  3023 #define replace_dv(M, P, S) {\
  3024   size_t DVS = M->dvsize;\
  3025   if (DVS != 0) {\
  3026     mchunkptr DV = M->dv;\
  3027     assert(is_small(DVS));\
  3028     insert_small_chunk(M, DV, DVS);\
  3029   }\
  3030   M->dvsize = S;\
  3031   M->dv = P;\
  3032 }
  3033 
  3034 /* ------------------------- Operations on trees ------------------------- */
  3035 
  3036 /* Insert chunk into tree */
  3037 #define insert_large_chunk(M, X, S) {\
  3038   tbinptr* H;\
  3039   bindex_t I;\
  3040   compute_tree_index(S, I);\
  3041   H = treebin_at(M, I);\
  3042   X->index = I;\
  3043   X->child[0] = X->child[1] = 0;\
  3044   if (!treemap_is_marked(M, I)) {\
  3045     mark_treemap(M, I);\
  3046     *H = X;\
  3047     X->parent = (tchunkptr)H;\
  3048     X->fd = X->bk = X;\
  3049   }\
  3050   else {\
  3051     tchunkptr T = *H;\
  3052     size_t K = S << leftshift_for_tree_index(I);\
  3053     for (;;) {\
  3054       if (chunksize(T) != S) {\
  3055         tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\
  3056         K <<= 1;\
  3057         if (*C != 0)\
  3058           T = *C;\
  3059         else if (RTCHECK(ok_address(M, C))) {\
  3060           *C = X;\
  3061           X->parent = T;\
  3062           X->fd = X->bk = X;\
  3063           break;\
  3064         }\
  3065         else {\
  3066           CORRUPTION_ERROR_ACTION(M);\
  3067           break;\
  3068         }\
  3069       }\
  3070       else {\
  3071         tchunkptr F = T->fd;\
  3072         if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\
  3073           T->fd = F->bk = X;\
  3074           X->fd = F;\
  3075           X->bk = T;\
  3076           X->parent = 0;\
  3077           break;\
  3078         }\
  3079         else {\
  3080           CORRUPTION_ERROR_ACTION(M);\
  3081           break;\
  3082         }\
  3083       }\
  3084     }\
  3085   }\
  3086 }
  3087 
  3088 /*
  3089   Unlink steps:
  3090 
  3091   1. If x is a chained node, unlink it from its same-sized fd/bk links
  3092      and choose its bk node as its replacement.
  3093   2. If x was the last node of its size, but not a leaf node, it must
  3094      be replaced with a leaf node (not merely one with an open left or
  3095      right), to make sure that lefts and rights of descendents
  3096      correspond properly to bit masks.  We use the rightmost descendent
  3097      of x.  We could use any other leaf, but this is easy to locate and
  3098      tends to counteract removal of leftmosts elsewhere, and so keeps
  3099      paths shorter than minimally guaranteed.  This doesn't loop much
  3100      because on average a node in a tree is near the bottom.
  3101   3. If x is the base of a chain (i.e., has parent links) relink
  3102      x's parent and children to x's replacement (or null if none).
  3103 */
  3104 
  3105 #define unlink_large_chunk(M, X) {\
  3106   tchunkptr XP = X->parent;\
  3107   tchunkptr R;\
  3108   if (X->bk != X) {\
  3109     tchunkptr F = X->fd;\
  3110     R = X->bk;\
  3111     if (RTCHECK(ok_address(M, F))) {\
  3112       F->bk = R;\
  3113       R->fd = F;\
  3114     }\
  3115     else {\
  3116       CORRUPTION_ERROR_ACTION(M);\
  3117     }\
  3118   }\
  3119   else {\
  3120     tchunkptr* RP;\
  3121     if (((R = *(RP = &(X->child[1]))) != 0) ||\
  3122         ((R = *(RP = &(X->child[0]))) != 0)) {\
  3123       tchunkptr* CP;\
  3124       while ((*(CP = &(R->child[1])) != 0) ||\
  3125              (*(CP = &(R->child[0])) != 0)) {\
  3126         R = *(RP = CP);\
  3127       }\
  3128       if (RTCHECK(ok_address(M, RP)))\
  3129         *RP = 0;\
  3130       else {\
  3131         CORRUPTION_ERROR_ACTION(M);\
  3132       }\
  3133     }\
  3134   }\
  3135   if (XP != 0) {\
  3136     tbinptr* H = treebin_at(M, X->index);\
  3137     if (X == *H) {\
  3138       if ((*H = R) == 0) \
  3139         clear_treemap(M, X->index);\
  3140     }\
  3141     else if (RTCHECK(ok_address(M, XP))) {\
  3142       if (XP->child[0] == X) \
  3143         XP->child[0] = R;\
  3144       else \
  3145         XP->child[1] = R;\
  3146     }\
  3147     else\
  3148       CORRUPTION_ERROR_ACTION(M);\
  3149     if (R != 0) {\
  3150       if (RTCHECK(ok_address(M, R))) {\
  3151         tchunkptr C0, C1;\
  3152         R->parent = XP;\
  3153         if ((C0 = X->child[0]) != 0) {\
  3154           if (RTCHECK(ok_address(M, C0))) {\
  3155             R->child[0] = C0;\
  3156             C0->parent = R;\
  3157           }\
  3158           else\
  3159             CORRUPTION_ERROR_ACTION(M);\
  3160         }\
  3161         if ((C1 = X->child[1]) != 0) {\
  3162           if (RTCHECK(ok_address(M, C1))) {\
  3163             R->child[1] = C1;\
  3164             C1->parent = R;\
  3165           }\
  3166           else\
  3167             CORRUPTION_ERROR_ACTION(M);\
  3168         }\
  3169       }\
  3170       else\
  3171         CORRUPTION_ERROR_ACTION(M);\
  3172     }\
  3173   }\
  3174 }
  3175 
  3176 /* Relays to large vs small bin operations */
  3177 
  3178 #define insert_chunk(M, P, S)\
  3179   if (is_small(S)) insert_small_chunk(M, P, S)\
  3180   else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); }
  3181 
  3182 #define unlink_chunk(M, P, S)\
  3183   if (is_small(S)) unlink_small_chunk(M, P, S)\
  3184   else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); }
  3185 
  3186 
  3187 /* Relays to internal calls to malloc/free from realloc, memalign etc */
  3188 
  3189 #if ONLY_MSPACES
  3190 #define internal_malloc(m, b) mspace_malloc(m, b)
  3191 #define internal_free(m, mem) mspace_free(m,mem);
  3192 #else /* ONLY_MSPACES */
  3193 #if MSPACES
  3194 #define internal_malloc(m, b)\
  3195    (m == gm)? dlmalloc(b) : mspace_malloc(m, b)
  3196 #define internal_free(m, mem)\
  3197    if (m == gm) dlfree(mem); else mspace_free(m,mem);
  3198 #else /* MSPACES */
  3199 #define internal_malloc(m, b) dlmalloc(b)
  3200 #define internal_free(m, mem) dlfree(mem)
  3201 #endif /* MSPACES */
  3202 #endif /* ONLY_MSPACES */
  3203 
  3204 /* -----------------------  Direct-mmapping chunks ----------------------- */
  3205 
  3206 /*
  3207   Directly mmapped chunks are set up with an offset to the start of
  3208   the mmapped region stored in the prev_foot field of the chunk. This
  3209   allows reconstruction of the required argument to MUNMAP when freed,
  3210   and also allows adjustment of the returned chunk to meet alignment
  3211   requirements (especially in memalign).  There is also enough space
  3212   allocated to hold a fake next chunk of size SIZE_T_SIZE to maintain
  3213   the PINUSE bit so frees can be checked.
  3214 */
  3215 
  3216 /* Malloc using mmap */
  3217 static void *
  3218 mmap_alloc(mstate m, size_t nb)
  3219 {
  3220     size_t mmsize =
  3221         granularity_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
  3222     if (mmsize > nb) {          /* Check for wrap around 0 */
  3223         char *mm = (char *) (DIRECT_MMAP(mmsize));
  3224         if (mm != CMFAIL) {
  3225             size_t offset = align_offset(chunk2mem(mm));
  3226             size_t psize = mmsize - offset - MMAP_FOOT_PAD;
  3227             mchunkptr p = (mchunkptr) (mm + offset);
  3228             p->prev_foot = offset | IS_MMAPPED_BIT;
  3229             (p)->head = (psize | CINUSE_BIT);
  3230             mark_inuse_foot(m, p, psize);
  3231             chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
  3232             chunk_plus_offset(p, psize + SIZE_T_SIZE)->head = 0;
  3233 
  3234             if (mm < m->least_addr)
  3235                 m->least_addr = mm;
  3236             if ((m->footprint += mmsize) > m->max_footprint)
  3237                 m->max_footprint = m->footprint;
  3238             assert(is_aligned(chunk2mem(p)));
  3239             check_mmapped_chunk(m, p);
  3240             return chunk2mem(p);
  3241         }
  3242     }
  3243     return 0;
  3244 }
  3245 
  3246 /* Realloc using mmap */
  3247 static mchunkptr
  3248 mmap_resize(mstate m, mchunkptr oldp, size_t nb)
  3249 {
  3250     size_t oldsize = chunksize(oldp);
  3251     if (is_small(nb))           /* Can't shrink mmap regions below small size */
  3252         return 0;
  3253     /* Keep old chunk if big enough but not too big */
  3254     if (oldsize >= nb + SIZE_T_SIZE &&
  3255         (oldsize - nb) <= (mparams.granularity << 1))
  3256         return oldp;
  3257     else {
  3258         size_t offset = oldp->prev_foot & ~IS_MMAPPED_BIT;
  3259         size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
  3260         size_t newmmsize = granularity_align(nb + SIX_SIZE_T_SIZES +
  3261                                              CHUNK_ALIGN_MASK);
  3262         char *cp = (char *) CALL_MREMAP((char *) oldp - offset,
  3263                                         oldmmsize, newmmsize, 1);
  3264         if (cp != CMFAIL) {
  3265             mchunkptr newp = (mchunkptr) (cp + offset);
  3266             size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
  3267             newp->head = (psize | CINUSE_BIT);
  3268             mark_inuse_foot(m, newp, psize);
  3269             chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
  3270             chunk_plus_offset(newp, psize + SIZE_T_SIZE)->head = 0;
  3271 
  3272             if (cp < m->least_addr)
  3273                 m->least_addr = cp;
  3274             if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
  3275                 m->max_footprint = m->footprint;
  3276             check_mmapped_chunk(m, newp);
  3277             return newp;
  3278         }
  3279     }
  3280     return 0;
  3281 }
  3282 
  3283 /* -------------------------- mspace management -------------------------- */
  3284 
  3285 /* Initialize top chunk and its size */
  3286 static void
  3287 init_top(mstate m, mchunkptr p, size_t psize)
  3288 {
  3289     /* Ensure alignment */
  3290     size_t offset = align_offset(chunk2mem(p));
  3291     p = (mchunkptr) ((char *) p + offset);
  3292     psize -= offset;
  3293 
  3294     m->top = p;
  3295     m->topsize = psize;
  3296     p->head = psize | PINUSE_BIT;
  3297     /* set size of fake trailing chunk holding overhead space only once */
  3298     chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE;
  3299     m->trim_check = mparams.trim_threshold;     /* reset on each update */
  3300 }
  3301 
  3302 /* Initialize bins for a new mstate that is otherwise zeroed out */
  3303 static void
  3304 init_bins(mstate m)
  3305 {
  3306     /* Establish circular links for smallbins */
  3307     bindex_t i;
  3308     for (i = 0; i < NSMALLBINS; ++i) {
  3309         sbinptr bin = smallbin_at(m, i);
  3310         bin->fd = bin->bk = bin;
  3311     }
  3312 }
  3313 
  3314 #if PROCEED_ON_ERROR
  3315 
  3316 /* default corruption action */
  3317 static void
  3318 reset_on_error(mstate m)
  3319 {
  3320     int i;
  3321     ++malloc_corruption_error_count;
  3322     /* Reinitialize fields to forget about all memory */
  3323     m->smallbins = m->treebins = 0;
  3324     m->dvsize = m->topsize = 0;
  3325     m->seg.base = 0;
  3326     m->seg.size = 0;
  3327     m->seg.next = 0;
  3328     m->top = m->dv = 0;
  3329     for (i = 0; i < NTREEBINS; ++i)
  3330         *treebin_at(m, i) = 0;
  3331     init_bins(m);
  3332 }
  3333 #endif /* PROCEED_ON_ERROR */
  3334 
  3335 /* Allocate chunk and prepend remainder with chunk in successor base. */
  3336 static void *
  3337 prepend_alloc(mstate m, char *newbase, char *oldbase, size_t nb)
  3338 {
  3339     mchunkptr p = align_as_chunk(newbase);
  3340     mchunkptr oldfirst = align_as_chunk(oldbase);
  3341     size_t psize = (char *) oldfirst - (char *) p;
  3342     mchunkptr q = chunk_plus_offset(p, nb);
  3343     size_t qsize = psize - nb;
  3344     set_size_and_pinuse_of_inuse_chunk(m, p, nb);
  3345 
  3346     assert((char *) oldfirst > (char *) q);
  3347     assert(pinuse(oldfirst));
  3348     assert(qsize >= MIN_CHUNK_SIZE);
  3349 
  3350     /* consolidate remainder with first chunk of old base */
  3351     if (oldfirst == m->top) {
  3352         size_t tsize = m->topsize += qsize;
  3353         m->top = q;
  3354         q->head = tsize | PINUSE_BIT;
  3355         check_top_chunk(m, q);
  3356     } else if (oldfirst == m->dv) {
  3357         size_t dsize = m->dvsize += qsize;
  3358         m->dv = q;
  3359         set_size_and_pinuse_of_free_chunk(q, dsize);
  3360     } else {
  3361         if (!cinuse(oldfirst)) {
  3362             size_t nsize = chunksize(oldfirst);
  3363             unlink_chunk(m, oldfirst, nsize);
  3364             oldfirst = chunk_plus_offset(oldfirst, nsize);
  3365             qsize += nsize;
  3366         }
  3367         set_free_with_pinuse(q, qsize, oldfirst);
  3368         insert_chunk(m, q, qsize);
  3369         check_free_chunk(m, q);
  3370     }
  3371 
  3372     check_malloced_chunk(m, chunk2mem(p), nb);
  3373     return chunk2mem(p);
  3374 }
  3375 
  3376 
  3377 /* Add a segment to hold a new noncontiguous region */
  3378 static void
  3379 add_segment(mstate m, char *tbase, size_t tsize, flag_t mmapped)
  3380 {
  3381     /* Determine locations and sizes of segment, fenceposts, old top */
  3382     char *old_top = (char *) m->top;
  3383     msegmentptr oldsp = segment_holding(m, old_top);
  3384     char *old_end = oldsp->base + oldsp->size;
  3385     size_t ssize = pad_request(sizeof(struct malloc_segment));
  3386     char *rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
  3387     size_t offset = align_offset(chunk2mem(rawsp));
  3388     char *asp = rawsp + offset;
  3389     char *csp = (asp < (old_top + MIN_CHUNK_SIZE)) ? old_top : asp;
  3390     mchunkptr sp = (mchunkptr) csp;
  3391     msegmentptr ss = (msegmentptr) (chunk2mem(sp));
  3392     mchunkptr tnext = chunk_plus_offset(sp, ssize);
  3393     mchunkptr p = tnext;
  3394     int nfences = 0;
  3395 
  3396     /* reset top to new space */
  3397     init_top(m, (mchunkptr) tbase, tsize - TOP_FOOT_SIZE);
  3398 
  3399     /* Set up segment record */
  3400     assert(is_aligned(ss));
  3401     set_size_and_pinuse_of_inuse_chunk(m, sp, ssize);
  3402     *ss = m->seg;               /* Push current record */
  3403     m->seg.base = tbase;
  3404     m->seg.size = tsize;
  3405     m->seg.sflags = mmapped;
  3406     m->seg.next = ss;
  3407 
  3408     /* Insert trailing fenceposts */
  3409     for (;;) {
  3410         mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE);
  3411         p->head = FENCEPOST_HEAD;
  3412         ++nfences;
  3413         if ((char *) (&(nextp->head)) < old_end)
  3414             p = nextp;
  3415         else
  3416             break;
  3417     }
  3418     assert(nfences >= 2);
  3419 
  3420     /* Insert the rest of old top into a bin as an ordinary free chunk */
  3421     if (csp != old_top) {
  3422         mchunkptr q = (mchunkptr) old_top;
  3423         size_t psize = csp - old_top;
  3424         mchunkptr tn = chunk_plus_offset(q, psize);
  3425         set_free_with_pinuse(q, psize, tn);
  3426         insert_chunk(m, q, psize);
  3427     }
  3428 
  3429     check_top_chunk(m, m->top);
  3430 }
  3431 
  3432 /* -------------------------- System allocation -------------------------- */
  3433 
  3434 /* Get memory from system using MORECORE or MMAP */
  3435 static void *
  3436 sys_alloc(mstate m, size_t nb)
  3437 {
  3438     char *tbase = CMFAIL;
  3439     size_t tsize = 0;
  3440     flag_t mmap_flag = 0;
  3441 
  3442     init_mparams();
  3443 
  3444     /* Directly map large chunks */
  3445     if (use_mmap(m) && nb >= mparams.mmap_threshold) {
  3446         void *mem = mmap_alloc(m, nb);
  3447         if (mem != 0)
  3448             return mem;
  3449     }
  3450 
  3451     /*
  3452        Try getting memory in any of three ways (in most-preferred to
  3453        least-preferred order):
  3454        1. A call to MORECORE that can normally contiguously extend memory.
  3455        (disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or
  3456        or main space is mmapped or a previous contiguous call failed)
  3457        2. A call to MMAP new space (disabled if not HAVE_MMAP).
  3458        Note that under the default settings, if MORECORE is unable to
  3459        fulfill a request, and HAVE_MMAP is true, then mmap is
  3460        used as a noncontiguous system allocator. This is a useful backup
  3461        strategy for systems with holes in address spaces -- in this case
  3462        sbrk cannot contiguously expand the heap, but mmap may be able to
  3463        find space.
  3464        3. A call to MORECORE that cannot usually contiguously extend memory.
  3465        (disabled if not HAVE_MORECORE)
  3466      */
  3467 
  3468     if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) {
  3469         char *br = CMFAIL;
  3470         msegmentptr ss =
  3471             (m->top == 0) ? 0 : segment_holding(m, (char *) m->top);
  3472         size_t asize = 0;
  3473         ACQUIRE_MORECORE_LOCK();
  3474 
  3475         if (ss == 0) {          /* First time through or recovery */
  3476             char *base = (char *) CALL_MORECORE(0);
  3477             if (base != CMFAIL) {
  3478                 asize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
  3479                 /* Adjust to end on a page boundary */
  3480                 if (!is_page_aligned(base))
  3481                     asize += (page_align((size_t) base) - (size_t) base);
  3482                 /* Can't call MORECORE if size is negative when treated as signed */
  3483                 if (asize < HALF_MAX_SIZE_T &&
  3484                     (br = (char *) (CALL_MORECORE(asize))) == base) {
  3485                     tbase = base;
  3486                     tsize = asize;
  3487                 }
  3488             }
  3489         } else {
  3490             /* Subtract out existing available top space from MORECORE request. */
  3491             asize =
  3492                 granularity_align(nb - m->topsize + TOP_FOOT_SIZE +
  3493                                   SIZE_T_ONE);
  3494             /* Use mem here only if it did continuously extend old space */
  3495             if (asize < HALF_MAX_SIZE_T &&
  3496                 (br =
  3497                  (char *) (CALL_MORECORE(asize))) == ss->base + ss->size) {
  3498                 tbase = br;
  3499                 tsize = asize;
  3500             }
  3501         }
  3502 
  3503         if (tbase == CMFAIL) {  /* Cope with partial failure */
  3504             if (br != CMFAIL) { /* Try to use/extend the space we did get */
  3505                 if (asize < HALF_MAX_SIZE_T &&
  3506                     asize < nb + TOP_FOOT_SIZE + SIZE_T_ONE) {
  3507                     size_t esize =
  3508                         granularity_align(nb + TOP_FOOT_SIZE +
  3509                                           SIZE_T_ONE - asize);
  3510                     if (esize < HALF_MAX_SIZE_T) {
  3511                         char *end = (char *) CALL_MORECORE(esize);
  3512                         if (end != CMFAIL)
  3513                             asize += esize;
  3514                         else {  /* Can't use; try to release */
  3515                             end = (char *) CALL_MORECORE(-asize);
  3516                             br = CMFAIL;
  3517                         }
  3518                     }
  3519                 }
  3520             }
  3521             if (br != CMFAIL) { /* Use the space we did get */
  3522                 tbase = br;
  3523                 tsize = asize;
  3524             } else
  3525                 disable_contiguous(m);  /* Don't try contiguous path in the future */
  3526         }
  3527 
  3528         RELEASE_MORECORE_LOCK();
  3529     }
  3530 
  3531     if (HAVE_MMAP && tbase == CMFAIL) { /* Try MMAP */
  3532         size_t req = nb + TOP_FOOT_SIZE + SIZE_T_ONE;
  3533         size_t rsize = granularity_align(req);
  3534         if (rsize > nb) {       /* Fail if wraps around zero */
  3535             char *mp = (char *) (CALL_MMAP(rsize));
  3536             if (mp != CMFAIL) {
  3537                 tbase = mp;
  3538                 tsize = rsize;
  3539                 mmap_flag = IS_MMAPPED_BIT;
  3540             }
  3541         }
  3542     }
  3543 
  3544     if (HAVE_MORECORE && tbase == CMFAIL) {     /* Try noncontiguous MORECORE */
  3545         size_t asize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
  3546         if (asize < HALF_MAX_SIZE_T) {
  3547             char *br = CMFAIL;
  3548             char *end = CMFAIL;
  3549             ACQUIRE_MORECORE_LOCK();
  3550             br = (char *) (CALL_MORECORE(asize));
  3551             end = (char *) (CALL_MORECORE(0));
  3552             RELEASE_MORECORE_LOCK();
  3553             if (br != CMFAIL && end != CMFAIL && br < end) {
  3554                 size_t ssize = end - br;
  3555                 if (ssize > nb + TOP_FOOT_SIZE) {
  3556                     tbase = br;
  3557                     tsize = ssize;
  3558                 }
  3559             }
  3560         }
  3561     }
  3562 
  3563     if (tbase != CMFAIL) {
  3564 
  3565         if ((m->footprint += tsize) > m->max_footprint)
  3566             m->max_footprint = m->footprint;
  3567 
  3568         if (!is_initialized(m)) {       /* first-time initialization */
  3569             m->seg.base = m->least_addr = tbase;
  3570             m->seg.size = tsize;
  3571             m->seg.sflags = mmap_flag;
  3572             m->magic = mparams.magic;
  3573             init_bins(m);
  3574             if (is_global(m))
  3575                 init_top(m, (mchunkptr) tbase, tsize - TOP_FOOT_SIZE);
  3576             else {
  3577                 /* Offset top by embedded malloc_state */
  3578                 mchunkptr mn = next_chunk(mem2chunk(m));
  3579                 init_top(m, mn,
  3580                          (size_t) ((tbase + tsize) - (char *) mn) -
  3581                          TOP_FOOT_SIZE);
  3582             }
  3583         }
  3584 
  3585         else {
  3586             /* Try to merge with an existing segment */
  3587             msegmentptr sp = &m->seg;
  3588             while (sp != 0 && tbase != sp->base + sp->size)
  3589                 sp = sp->next;
  3590             if (sp != 0 && !is_extern_segment(sp) && (sp->sflags & IS_MMAPPED_BIT) == mmap_flag && segment_holds(sp, m->top)) { /* append */
  3591                 sp->size += tsize;
  3592                 init_top(m, m->top, m->topsize + tsize);
  3593             } else {
  3594                 if (tbase < m->least_addr)
  3595                     m->least_addr = tbase;
  3596                 sp = &m->seg;
  3597                 while (sp != 0 && sp->base != tbase + tsize)
  3598                     sp = sp->next;
  3599                 if (sp != 0 &&
  3600                     !is_extern_segment(sp) &&
  3601                     (sp->sflags & IS_MMAPPED_BIT) == mmap_flag) {
  3602                     char *oldbase = sp->base;
  3603                     sp->base = tbase;
  3604                     sp->size += tsize;
  3605                     return prepend_alloc(m, tbase, oldbase, nb);
  3606                 } else
  3607                     add_segment(m, tbase, tsize, mmap_flag);
  3608             }
  3609         }
  3610 
  3611         if (nb < m->topsize) {  /* Allocate from new or extended top space */
  3612             size_t rsize = m->topsize -= nb;
  3613             mchunkptr p = m->top;
  3614             mchunkptr r = m->top = chunk_plus_offset(p, nb);
  3615             r->head = rsize | PINUSE_BIT;
  3616             set_size_and_pinuse_of_inuse_chunk(m, p, nb);
  3617             check_top_chunk(m, m->top);
  3618             check_malloced_chunk(m, chunk2mem(p), nb);
  3619             return chunk2mem(p);
  3620         }
  3621     }
  3622 
  3623     MALLOC_FAILURE_ACTION;
  3624     return 0;
  3625 }
  3626 
  3627 /* -----------------------  system deallocation -------------------------- */
  3628 
  3629 /* Unmap and unlink any mmapped segments that don't contain used chunks */
  3630 static size_t
  3631 release_unused_segments(mstate m)
  3632 {
  3633     size_t released = 0;
  3634     msegmentptr pred = &m->seg;
  3635     msegmentptr sp = pred->next;
  3636     while (sp != 0) {
  3637         char *base = sp->base;
  3638         size_t size = sp->size;
  3639         msegmentptr next = sp->next;
  3640         if (is_mmapped_segment(sp) && !is_extern_segment(sp)) {
  3641             mchunkptr p = align_as_chunk(base);
  3642             size_t psize = chunksize(p);
  3643             /* Can unmap if first chunk holds entire segment and not pinned */
  3644             if (!cinuse(p)
  3645                 && (char *) p + psize >= base + size - TOP_FOOT_SIZE) {
  3646                 tchunkptr tp = (tchunkptr) p;
  3647                 assert(segment_holds(sp, (char *) sp));
  3648                 if (p == m->dv) {
  3649                     m->dv = 0;
  3650                     m->dvsize = 0;
  3651                 } else {
  3652                     unlink_large_chunk(m, tp);
  3653                 }
  3654                 if (CALL_MUNMAP(base, size) == 0) {
  3655                     released += size;
  3656                     m->footprint -= size;
  3657                     /* unlink obsoleted record */
  3658                     sp = pred;
  3659                     sp->next = next;
  3660                 } else {        /* back out if cannot unmap */
  3661                     insert_large_chunk(m, tp, psize);
  3662                 }
  3663             }
  3664         }
  3665         pred = sp;
  3666         sp = next;
  3667     }
  3668     return released;
  3669 }
  3670 
  3671 static int
  3672 sys_trim(mstate m, size_t pad)
  3673 {
  3674     size_t released = 0;
  3675     if (pad < MAX_REQUEST && is_initialized(m)) {
  3676         pad += TOP_FOOT_SIZE;   /* ensure enough room for segment overhead */
  3677 
  3678         if (m->topsize > pad) {
  3679             /* Shrink top space in granularity-size units, keeping at least one */
  3680             size_t unit = mparams.granularity;
  3681             size_t extra =
  3682                 ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit -
  3683                  SIZE_T_ONE) * unit;
  3684             msegmentptr sp = segment_holding(m, (char *) m->top);
  3685 
  3686             if (!is_extern_segment(sp)) {
  3687                 if (is_mmapped_segment(sp)) {
  3688                     if (HAVE_MMAP && sp->size >= extra && !has_segment_link(m, sp)) {   /* can't shrink if pinned */
  3689                         size_t newsize = sp->size - extra;
  3690                         /* Prefer mremap, fall back to munmap */
  3691                         if ((CALL_MREMAP
  3692                              (sp->base, sp->size, newsize, 0) != MFAIL)
  3693                             || (CALL_MUNMAP(sp->base + newsize, extra)
  3694                                 == 0)) {
  3695                             released = extra;
  3696                         }
  3697                     }
  3698                 } else if (HAVE_MORECORE) {
  3699                     if (extra >= HALF_MAX_SIZE_T)       /* Avoid wrapping negative */
  3700                         extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit;
  3701                     ACQUIRE_MORECORE_LOCK();
  3702                     {
  3703                         /* Make sure end of memory is where we last set it. */
  3704                         char *old_br = (char *) (CALL_MORECORE(0));
  3705                         if (old_br == sp->base + sp->size) {
  3706                             char *rel_br = (char *) (CALL_MORECORE(-extra));
  3707                             char *new_br = (char *) (CALL_MORECORE(0));
  3708                             if (rel_br != CMFAIL && new_br < old_br)
  3709                                 released = old_br - new_br;
  3710                         }
  3711                     }
  3712                     RELEASE_MORECORE_LOCK();
  3713                 }
  3714             }
  3715 
  3716             if (released != 0) {
  3717                 sp->size -= released;
  3718                 m->footprint -= released;
  3719                 init_top(m, m->top, m->topsize - released);
  3720                 check_top_chunk(m, m->top);
  3721             }
  3722         }
  3723 
  3724         /* Unmap any unused mmapped segments */
  3725         if (HAVE_MMAP)
  3726             released += release_unused_segments(m);
  3727 
  3728         /* On failure, disable autotrim to avoid repeated failed future calls */
  3729         if (released == 0)
  3730             m->trim_check = MAX_SIZE_T;
  3731     }
  3732 
  3733     return (released != 0) ? 1 : 0;
  3734 }
  3735 
  3736 /* ---------------------------- malloc support --------------------------- */
  3737 
  3738 /* allocate a large request from the best fitting chunk in a treebin */
  3739 static void *
  3740 tmalloc_large(mstate m, size_t nb)
  3741 {
  3742     tchunkptr v = 0;
  3743     size_t rsize = -nb;         /* Unsigned negation */
  3744     tchunkptr t;
  3745     bindex_t idx;
  3746     compute_tree_index(nb, idx);
  3747 
  3748     if ((t = *treebin_at(m, idx)) != 0) {
  3749         /* Traverse tree for this bin looking for node with size == nb */
  3750         size_t sizebits = nb << leftshift_for_tree_index(idx);
  3751         tchunkptr rst = 0;      /* The deepest untaken right subtree */
  3752         for (;;) {
  3753             tchunkptr rt;
  3754             size_t trem = chunksize(t) - nb;
  3755             if (trem < rsize) {
  3756                 v = t;
  3757                 if ((rsize = trem) == 0)
  3758                     break;
  3759             }
  3760             rt = t->child[1];
  3761             t = t->child[(sizebits >> (SIZE_T_BITSIZE - SIZE_T_ONE)) & 1];
  3762             if (rt != 0 && rt != t)
  3763                 rst = rt;
  3764             if (t == 0) {
  3765                 t = rst;        /* set t to least subtree holding sizes > nb */
  3766                 break;
  3767             }
  3768             sizebits <<= 1;
  3769         }
  3770     }
  3771 
  3772     if (t == 0 && v == 0) {     /* set t to root of next non-empty treebin */
  3773         binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap;
  3774         if (leftbits != 0) {
  3775             bindex_t i;
  3776             binmap_t leastbit = least_bit(leftbits);
  3777             compute_bit2idx(leastbit, i);
  3778             t = *treebin_at(m, i);
  3779         }
  3780     }
  3781 
  3782     while (t != 0) {            /* find smallest of tree or subtree */
  3783         size_t trem = chunksize(t) - nb;
  3784         if (trem < rsize) {
  3785             rsize = trem;
  3786             v = t;
  3787         }
  3788         t = leftmost_child(t);
  3789     }
  3790 
  3791     /*  If dv is a better fit, return 0 so malloc will use it */
  3792     if (v != 0 && rsize < (size_t) (m->dvsize - nb)) {
  3793         if (RTCHECK(ok_address(m, v))) {        /* split */
  3794             mchunkptr r = chunk_plus_offset(v, nb);
  3795             assert(chunksize(v) == rsize + nb);
  3796             if (RTCHECK(ok_next(v, r))) {
  3797                 unlink_large_chunk(m, v);
  3798                 if (rsize < MIN_CHUNK_SIZE)
  3799                     set_inuse_and_pinuse(m, v, (rsize + nb));
  3800                 else {
  3801                     set_size_and_pinuse_of_inuse_chunk(m, v, nb);
  3802                     set_size_and_pinuse_of_free_chunk(r, rsize);
  3803                     insert_chunk(m, r, rsize);
  3804                 }
  3805                 return chunk2mem(v);
  3806             }
  3807         }
  3808         CORRUPTION_ERROR_ACTION(m);
  3809     }
  3810     return 0;
  3811 }
  3812 
  3813 /* allocate a small request from the best fitting chunk in a treebin */
  3814 static void *
  3815 tmalloc_small(mstate m, size_t nb)
  3816 {
  3817     tchunkptr t, v;
  3818     size_t rsize;
  3819     bindex_t i;
  3820     binmap_t leastbit = least_bit(m->treemap);
  3821     compute_bit2idx(leastbit, i);
  3822 
  3823     v = t = *treebin_at(m, i);
  3824     rsize = chunksize(t) - nb;
  3825 
  3826     while ((t = leftmost_child(t)) != 0) {
  3827         size_t trem = chunksize(t) - nb;
  3828         if (trem < rsize) {
  3829             rsize = trem;
  3830             v = t;
  3831         }
  3832     }
  3833 
  3834     if (RTCHECK(ok_address(m, v))) {
  3835         mchunkptr r = chunk_plus_offset(v, nb);
  3836         assert(chunksize(v) == rsize + nb);
  3837         if (RTCHECK(ok_next(v, r))) {
  3838             unlink_large_chunk(m, v);
  3839             if (rsize < MIN_CHUNK_SIZE)
  3840                 set_inuse_and_pinuse(m, v, (rsize + nb));
  3841             else {
  3842                 set_size_and_pinuse_of_inuse_chunk(m, v, nb);
  3843                 set_size_and_pinuse_of_free_chunk(r, rsize);
  3844                 replace_dv(m, r, rsize);
  3845             }
  3846             return chunk2mem(v);
  3847         }
  3848     }
  3849 
  3850     CORRUPTION_ERROR_ACTION(m);
  3851     return 0;
  3852 }
  3853 
  3854 /* --------------------------- realloc support --------------------------- */
  3855 
  3856 static void *
  3857 internal_realloc(mstate m, void *oldmem, size_t bytes)
  3858 {
  3859     if (bytes >= MAX_REQUEST) {
  3860         MALLOC_FAILURE_ACTION;
  3861         return 0;
  3862     }
  3863     if (!PREACTION(m)) {
  3864         mchunkptr oldp = mem2chunk(oldmem);
  3865         size_t oldsize = chunksize(oldp);
  3866         mchunkptr next = chunk_plus_offset(oldp, oldsize);
  3867         mchunkptr newp = 0;
  3868         void *extra = 0;
  3869 
  3870         /* Try to either shrink or extend into top. Else malloc-copy-free */
  3871 
  3872         if (RTCHECK(ok_address(m, oldp) && ok_cinuse(oldp) &&
  3873                     ok_next(oldp, next) && ok_pinuse(next))) {
  3874             size_t nb = request2size(bytes);
  3875             if (is_mmapped(oldp))
  3876                 newp = mmap_resize(m, oldp, nb);
  3877             else if (oldsize >= nb) {   /* already big enough */
  3878                 size_t rsize = oldsize - nb;
  3879                 newp = oldp;
  3880                 if (rsize >= MIN_CHUNK_SIZE) {
  3881                     mchunkptr remainder = chunk_plus_offset(newp, nb);
  3882                     set_inuse(m, newp, nb);
  3883                     set_inuse(m, remainder, rsize);
  3884                     extra = chunk2mem(remainder);
  3885                 }
  3886             } else if (next == m->top && oldsize + m->topsize > nb) {
  3887                 /* Expand into top */
  3888                 size_t newsize = oldsize + m->topsize;
  3889                 size_t newtopsize = newsize - nb;
  3890                 mchunkptr newtop = chunk_plus_offset(oldp, nb);
  3891                 set_inuse(m, oldp, nb);
  3892                 newtop->head = newtopsize | PINUSE_BIT;
  3893                 m->top = newtop;
  3894                 m->topsize = newtopsize;
  3895                 newp = oldp;
  3896             }
  3897         } else {
  3898             USAGE_ERROR_ACTION(m, oldmem);
  3899             POSTACTION(m);
  3900             return 0;
  3901         }
  3902 
  3903         POSTACTION(m);
  3904 
  3905         if (newp != 0) {
  3906             if (extra != 0) {
  3907                 internal_free(m, extra);
  3908             }
  3909             check_inuse_chunk(m, newp);
  3910             return chunk2mem(newp);
  3911         } else {
  3912             void *newmem = internal_malloc(m, bytes);
  3913             if (newmem != 0) {
  3914                 size_t oc = oldsize - overhead_for(oldp);
  3915                 SDL_memcpy(newmem, oldmem, (oc < bytes) ? oc : bytes);
  3916                 internal_free(m, oldmem);
  3917             }
  3918             return newmem;
  3919         }
  3920     }
  3921     return 0;
  3922 }
  3923 
  3924 /* --------------------------- memalign support -------------------------- */
  3925 
  3926 static void *
  3927 internal_memalign(mstate m, size_t alignment, size_t bytes)
  3928 {
  3929     if (alignment <= MALLOC_ALIGNMENT)  /* Can just use malloc */
  3930         return internal_malloc(m, bytes);
  3931     if (alignment < MIN_CHUNK_SIZE)     /* must be at least a minimum chunk size */
  3932         alignment = MIN_CHUNK_SIZE;
  3933     if ((alignment & (alignment - SIZE_T_ONE)) != 0) {  /* Ensure a power of 2 */
  3934         size_t a = MALLOC_ALIGNMENT << 1;
  3935         while (a < alignment)
  3936             a <<= 1;
  3937         alignment = a;
  3938     }
  3939 
  3940     if (bytes >= MAX_REQUEST - alignment) {
  3941         if (m != 0) {           /* Test isn't needed but avoids compiler warning */
  3942             MALLOC_FAILURE_ACTION;
  3943         }
  3944     } else {
  3945         size_t nb = request2size(bytes);
  3946         size_t req = nb + alignment + MIN_CHUNK_SIZE - CHUNK_OVERHEAD;
  3947         char *mem = (char *) internal_malloc(m, req);
  3948         if (mem != 0) {
  3949             void *leader = 0;
  3950             void *trailer = 0;
  3951             mchunkptr p = mem2chunk(mem);
  3952 
  3953             if (PREACTION(m))
  3954                 return 0;
  3955             if ((((size_t) (mem)) % alignment) != 0) {  /* misaligned */
  3956                 /*
  3957                    Find an aligned spot inside chunk.  Since we need to give
  3958                    back leading space in a chunk of at least MIN_CHUNK_SIZE, if
  3959                    the first calculation places us at a spot with less than
  3960                    MIN_CHUNK_SIZE leader, we can move to the next aligned spot.
  3961                    We've allocated enough total room so that this is always
  3962                    possible.
  3963                  */
  3964                 char *br = (char *)
  3965                     mem2chunk((size_t)
  3966                               (((size_t)
  3967                                 (mem + alignment -
  3968                                  SIZE_T_ONE)) & -alignment));
  3969                 char *pos =
  3970                     ((size_t) (br - (char *) (p)) >=
  3971                      MIN_CHUNK_SIZE) ? br : br + alignment;
  3972                 mchunkptr newp = (mchunkptr) pos;
  3973                 size_t leadsize = pos - (char *) (p);
  3974                 size_t newsize = chunksize(p) - leadsize;
  3975 
  3976                 if (is_mmapped(p)) {    /* For mmapped chunks, just adjust offset */
  3977                     newp->prev_foot = p->prev_foot + leadsize;
  3978                     newp->head = (newsize | CINUSE_BIT);
  3979                 } else {        /* Otherwise, give back leader, use the rest */
  3980                     set_inuse(m, newp, newsize);
  3981                     set_inuse(m, p, leadsize);
  3982                     leader = chunk2mem(p);
  3983                 }
  3984                 p = newp;
  3985             }
  3986 
  3987             /* Give back spare room at the end */
  3988             if (!is_mmapped(p)) {
  3989                 size_t size = chunksize(p);
  3990                 if (size > nb + MIN_CHUNK_SIZE) {
  3991                     size_t remainder_size = size - nb;
  3992                     mchunkptr remainder = chunk_plus_offset(p, nb);
  3993                     set_inuse(m, p, nb);
  3994                     set_inuse(m, remainder, remainder_size);
  3995                     trailer = chunk2mem(remainder);
  3996                 }
  3997             }
  3998 
  3999             assert(chunksize(p) >= nb);
  4000             assert((((size_t) (chunk2mem(p))) % alignment) == 0);
  4001             check_inuse_chunk(m, p);
  4002             POSTACTION(m);
  4003             if (leader != 0) {
  4004                 internal_free(m, leader);
  4005             }
  4006             if (trailer != 0) {
  4007                 internal_free(m, trailer);
  4008             }
  4009             return chunk2mem(p);
  4010         }
  4011     }
  4012     return 0;
  4013 }
  4014 
  4015 /* ------------------------ comalloc/coalloc support --------------------- */
  4016 
  4017 static void **
  4018 ialloc(mstate m, size_t n_elements, size_t * sizes, int opts, void *chunks[])
  4019 {
  4020     /*
  4021        This provides common support for independent_X routines, handling
  4022        all of the combinations that can result.
  4023 
  4024        The opts arg has:
  4025        bit 0 set if all elements are same size (using sizes[0])
  4026        bit 1 set if elements should be zeroed
  4027      */
  4028 
  4029     size_t element_size;        /* chunksize of each element, if all same */
  4030     size_t contents_size;       /* total size of elements */
  4031     size_t array_size;          /* request size of pointer array */
  4032     void *mem;                  /* malloced aggregate space */
  4033     mchunkptr p;                /* corresponding chunk */
  4034     size_t remainder_size;      /* remaining bytes while splitting */
  4035     void **marray;              /* either "chunks" or malloced ptr array */
  4036     mchunkptr array_chunk;      /* chunk for malloced ptr array */
  4037     flag_t was_enabled;         /* to disable mmap */
  4038     size_t size;
  4039     size_t i;
  4040 
  4041     /* compute array length, if needed */
  4042     if (chunks != 0) {
  4043         if (n_elements == 0)
  4044             return chunks;      /* nothing to do */
  4045         marray = chunks;
  4046         array_size = 0;
  4047     } else {
  4048         /* if empty req, must still return chunk representing empty array */
  4049         if (n_elements == 0)
  4050             return (void **) internal_malloc(m, 0);
  4051         marray = 0;
  4052         array_size = request2size(n_elements * (sizeof(void *)));
  4053     }
  4054 
  4055     /* compute total element size */
  4056     if (opts & 0x1) {           /* all-same-size */
  4057         element_size = request2size(*sizes);
  4058         contents_size = n_elements * element_size;
  4059     } else {                    /* add up all the sizes */
  4060         element_size = 0;
  4061         contents_size = 0;
  4062         for (i = 0; i != n_elements; ++i)
  4063             contents_size += request2size(sizes[i]);
  4064     }
  4065 
  4066     size = contents_size + array_size;
  4067 
  4068     /*
  4069        Allocate the aggregate chunk.  First disable direct-mmapping so
  4070        malloc won't use it, since we would not be able to later
  4071        free/realloc space internal to a segregated mmap region.
  4072      */
  4073     was_enabled = use_mmap(m);
  4074     disable_mmap(m);
  4075     mem = internal_malloc(m, size - CHUNK_OVERHEAD);
  4076     if (was_enabled)
  4077         enable_mmap(m);
  4078     if (mem == 0)
  4079         return 0;
  4080 
  4081     if (PREACTION(m))
  4082         return 0;
  4083     p = mem2chunk(mem);
  4084     remainder_size = chunksize(p);
  4085 
  4086     assert(!is_mmapped(p));
  4087 
  4088     if (opts & 0x2) {           /* optionally clear the elements */
  4089         memset((size_t *) mem, 0, remainder_size - SIZE_T_SIZE - array_size);
  4090     }
  4091 
  4092     /* If not provided, allocate the pointer array as final part of chunk */
  4093     if (marray == 0) {
  4094         size_t array_chunk_size;
  4095         array_chunk = chunk_plus_offset(p, contents_size);
  4096         array_chunk_size = remainder_size - contents_size;
  4097         marray = (void **) (chunk2mem(array_chunk));
  4098         set_size_and_pinuse_of_inuse_chunk(m, array_chunk, array_chunk_size);
  4099         remainder_size = contents_size;
  4100     }
  4101 
  4102     /* split out elements */
  4103     for (i = 0;; ++i) {
  4104         marray[i] = chunk2mem(p);
  4105         if (i != n_elements - 1) {
  4106             if (element_size != 0)
  4107                 size = element_size;
  4108             else
  4109                 size = request2size(sizes[i]);
  4110             remainder_size -= size;
  4111             set_size_and_pinuse_of_inuse_chunk(m, p, size);
  4112             p = chunk_plus_offset(p, size);
  4113         } else {                /* the final element absorbs any overallocation slop */
  4114             set_size_and_pinuse_of_inuse_chunk(m, p, remainder_size);
  4115             break;
  4116         }
  4117     }
  4118 
  4119 #if DEBUG
  4120     if (marray != chunks) {
  4121         /* final element must have exactly exhausted chunk */
  4122         if (element_size != 0) {
  4123             assert(remainder_size == element_size);
  4124         } else {
  4125             assert(remainder_size == request2size(sizes[i]));
  4126         }
  4127         check_inuse_chunk(m, mem2chunk(marray));
  4128     }
  4129     for (i = 0; i != n_elements; ++i)
  4130         check_inuse_chunk(m, mem2chunk(marray[i]));
  4131 
  4132 #endif /* DEBUG */
  4133 
  4134     POSTACTION(m);
  4135     return marray;
  4136 }
  4137 
  4138 
  4139 /* -------------------------- public routines ---------------------------- */
  4140 
  4141 #if !ONLY_MSPACES
  4142 
  4143 void *
  4144 dlmalloc(size_t bytes)
  4145 {
  4146     /*
  4147        Basic algorithm:
  4148        If a small request (< 256 bytes minus per-chunk overhead):
  4149        1. If one exists, use a remainderless chunk in associated smallbin.
  4150        (Remainderless means that there are too few excess bytes to
  4151        represent as a chunk.)
  4152        2. If it is big enough, use the dv chunk, which is normally the
  4153        chunk adjacent to the one used for the most recent small request.
  4154        3. If one exists, split the smallest available chunk in a bin,
  4155        saving remainder in dv.
  4156        4. If it is big enough, use the top chunk.
  4157        5. If available, get memory from system and use it
  4158        Otherwise, for a large request:
  4159        1. Find the smallest available binned chunk that fits, and use it
  4160        if it is better fitting than dv chunk, splitting if necessary.
  4161        2. If better fitting than any binned chunk, use the dv chunk.
  4162        3. If it is big enough, use the top chunk.
  4163        4. If request size >= mmap threshold, try to directly mmap this chunk.
  4164        5. If available, get memory from system and use it
  4165 
  4166        The ugly goto's here ensure that postaction occurs along all paths.
  4167      */
  4168 
  4169     if (!PREACTION(gm)) {
  4170         void *mem;
  4171         size_t nb;
  4172         if (bytes <= MAX_SMALL_REQUEST) {
  4173             bindex_t idx;
  4174             binmap_t smallbits;
  4175             nb = (bytes < MIN_REQUEST) ? MIN_CHUNK_SIZE : pad_request(bytes);
  4176             idx = small_index(nb);
  4177             smallbits = gm->smallmap >> idx;
  4178 
  4179             if ((smallbits & 0x3U) != 0) {      /* Remainderless fit to a smallbin. */
  4180                 mchunkptr b, p;
  4181                 idx += ~smallbits & 1;  /* Uses next bin if idx empty */
  4182                 b = smallbin_at(gm, idx);
  4183                 p = b->fd;
  4184                 assert(chunksize(p) == small_index2size(idx));
  4185                 unlink_first_small_chunk(gm, b, p, idx);
  4186                 set_inuse_and_pinuse(gm, p, small_index2size(idx));
  4187                 mem = chunk2mem(p);
  4188                 check_malloced_chunk(gm, mem, nb);
  4189                 goto postaction;
  4190             }
  4191 
  4192             else if (nb > gm->dvsize) {
  4193                 if (smallbits != 0) {   /* Use chunk in next nonempty smallbin */
  4194                     mchunkptr b, p, r;
  4195                     size_t rsize;
  4196                     bindex_t i;
  4197                     binmap_t leftbits =
  4198                         (smallbits << idx) & left_bits(idx2bit(idx));
  4199                     binmap_t leastbit = least_bit(leftbits);
  4200                     compute_bit2idx(leastbit, i);
  4201                     b = smallbin_at(gm, i);
  4202                     p = b->fd;
  4203                     assert(chunksize(p) == small_index2size(i));
  4204                     unlink_first_small_chunk(gm, b, p, i);
  4205                     rsize = small_index2size(i) - nb;
  4206                     /* Fit here cannot be remainderless if 4byte sizes */
  4207                     if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
  4208                         set_inuse_and_pinuse(gm, p, small_index2size(i));
  4209                     else {
  4210                         set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
  4211                         r = chunk_plus_offset(p, nb);
  4212                         set_size_and_pinuse_of_free_chunk(r, rsize);
  4213                         replace_dv(gm, r, rsize);
  4214                     }
  4215                     mem = chunk2mem(p);
  4216                     check_malloced_chunk(gm, mem, nb);
  4217                     goto postaction;
  4218                 }
  4219 
  4220                 else if (gm->treemap != 0
  4221                          && (mem = tmalloc_small(gm, nb)) != 0) {
  4222                     check_malloced_chunk(gm, mem, nb);
  4223                     goto postaction;
  4224                 }
  4225             }
  4226         } else if (bytes >= MAX_REQUEST)
  4227             nb = MAX_SIZE_T;    /* Too big to allocate. Force failure (in sys alloc) */
  4228         else {
  4229             nb = pad_request(bytes);
  4230             if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) {
  4231                 check_malloced_chunk(gm, mem, nb);
  4232                 goto postaction;
  4233             }
  4234         }
  4235 
  4236         if (nb <= gm->dvsize) {
  4237             size_t rsize = gm->dvsize - nb;
  4238             mchunkptr p = gm->dv;
  4239             if (rsize >= MIN_CHUNK_SIZE) {      /* split dv */
  4240                 mchunkptr r = gm->dv = chunk_plus_offset(p, nb);
  4241                 gm->dvsize = rsize;
  4242                 set_size_and_pinuse_of_free_chunk(r, rsize);
  4243                 set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
  4244             } else {            /* exhaust dv */
  4245                 size_t dvs = gm->dvsize;
  4246                 gm->dvsize = 0;
  4247                 gm->dv = 0;
  4248                 set_inuse_and_pinuse(gm, p, dvs);
  4249             }
  4250             mem = chunk2mem(p);
  4251             check_malloced_chunk(gm, mem, nb);
  4252             goto postaction;
  4253         }
  4254 
  4255         else if (nb < gm->topsize) {    /* Split top */
  4256             size_t rsize = gm->topsize -= nb;
  4257             mchunkptr p = gm->top;
  4258             mchunkptr r = gm->top = chunk_plus_offset(p, nb);
  4259             r->head = rsize | PINUSE_BIT;
  4260             set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
  4261             mem = chunk2mem(p);
  4262             check_top_chunk(gm, gm->top);
  4263             check_malloced_chunk(gm, mem, nb);
  4264             goto postaction;
  4265         }
  4266 
  4267         mem = sys_alloc(gm, nb);
  4268 
  4269       postaction:
  4270         POSTACTION(gm);
  4271         return mem;
  4272     }
  4273 
  4274     return 0;
  4275 }
  4276 
  4277 void
  4278 dlfree(void *mem)
  4279 {
  4280     /*
  4281        Consolidate freed chunks with preceeding or succeeding bordering
  4282        free chunks, if they exist, and then place in a bin.  Intermixed
  4283        with special cases for top, dv, mmapped chunks, and usage errors.
  4284      */
  4285 
  4286     if (mem != 0) {
  4287         mchunkptr p = mem2chunk(mem);
  4288 #if FOOTERS
  4289         mstate fm = get_mstate_for(p);
  4290         if (!ok_magic(fm)) {
  4291             USAGE_ERROR_ACTION(fm, p);
  4292             return;
  4293         }
  4294 #else /* FOOTERS */
  4295 #define fm gm
  4296 #endif /* FOOTERS */
  4297         if (!PREACTION(fm)) {
  4298             check_inuse_chunk(fm, p);
  4299             if (RTCHECK(ok_address(fm, p) && ok_cinuse(p))) {
  4300                 size_t psize = chunksize(p);
  4301                 mchunkptr next = chunk_plus_offset(p, psize);
  4302                 if (!pinuse(p)) {
  4303                     size_t prevsize = p->prev_foot;
  4304                     if ((prevsize & IS_MMAPPED_BIT) != 0) {
  4305                         prevsize &= ~IS_MMAPPED_BIT;
  4306                         psize += prevsize + MMAP_FOOT_PAD;
  4307                         if (CALL_MUNMAP((char *) p - prevsize, psize) == 0)
  4308                             fm->footprint -= psize;
  4309                         goto postaction;
  4310                     } else {
  4311                         mchunkptr prev = chunk_minus_offset(p, prevsize);
  4312                         psize += prevsize;
  4313                         p = prev;
  4314                         if (RTCHECK(ok_address(fm, prev))) {    /* consolidate backward */
  4315                             if (p != fm->dv) {
  4316                                 unlink_chunk(fm, p, prevsize);
  4317                             } else if ((next->head & INUSE_BITS) ==
  4318                                        INUSE_BITS) {
  4319                                 fm->dvsize = psize;
  4320                                 set_free_with_pinuse(p, psize, next);
  4321                                 goto postaction;
  4322                             }
  4323                         } else
  4324                             goto erroraction;
  4325                     }
  4326                 }
  4327 
  4328                 if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
  4329                     if (!cinuse(next)) {        /* consolidate forward */
  4330                         if (next == fm->top) {
  4331                             size_t tsize = fm->topsize += psize;
  4332                             fm->top = p;
  4333                             p->head = tsize | PINUSE_BIT;
  4334                             if (p == fm->dv) {
  4335                                 fm->dv = 0;
  4336                                 fm->dvsize = 0;
  4337                             }
  4338                             if (should_trim(fm, tsize))
  4339                                 sys_trim(fm, 0);
  4340                             goto postaction;
  4341                         } else if (next == fm->dv) {
  4342                             size_t dsize = fm->dvsize += psize;
  4343                             fm->dv = p;
  4344                             set_size_and_pinuse_of_free_chunk(p, dsize);
  4345                             goto postaction;
  4346                         } else {
  4347                             size_t nsize = chunksize(next);
  4348                             psize += nsize;
  4349                             unlink_chunk(fm, next, nsize);
  4350                             set_size_and_pinuse_of_free_chunk(p, psize);
  4351                             if (p == fm->dv) {
  4352                                 fm->dvsize = psize;
  4353                                 goto postaction;
  4354                             }
  4355                         }
  4356                     } else
  4357                         set_free_with_pinuse(p, psize, next);
  4358                     insert_chunk(fm, p, psize);
  4359                     check_free_chunk(fm, p);
  4360                     goto postaction;
  4361                 }
  4362             }
  4363           erroraction:
  4364             USAGE_ERROR_ACTION(fm, p);
  4365           postaction:
  4366             POSTACTION(fm);
  4367         }
  4368     }
  4369 #if !FOOTERS
  4370 #undef fm
  4371 #endif /* FOOTERS */
  4372 }
  4373 
  4374 void *
  4375 dlcalloc(size_t n_elements, size_t elem_size)
  4376 {
  4377     void *mem;
  4378     size_t req = 0;
  4379     if (n_elements != 0) {
  4380         req = n_elements * elem_size;
  4381         if (((n_elements | elem_size) & ~(size_t) 0xffff) &&
  4382             (req / n_elements != elem_size))
  4383             req = MAX_SIZE_T;   /* force downstream failure on overflow */
  4384     }
  4385     mem = dlmalloc(req);
  4386     if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
  4387         memset(mem, 0, req);
  4388     return mem;
  4389 }
  4390 
  4391 void *
  4392 dlrealloc(void *oldmem, size_t bytes)
  4393 {
  4394     if (oldmem == 0)
  4395         return dlmalloc(bytes);
  4396 #ifdef REALLOC_ZERO_BYTES_FREES
  4397     if (bytes == 0) {
  4398         dlfree(oldmem);
  4399         return 0;
  4400     }
  4401 #endif /* REALLOC_ZERO_BYTES_FREES */
  4402     else {
  4403 #if ! FOOTERS
  4404         mstate m = gm;
  4405 #else /* FOOTERS */
  4406         mstate m = get_mstate_for(mem2chunk(oldmem));
  4407         if (!ok_magic(m)) {
  4408             USAGE_ERROR_ACTION(m, oldmem);
  4409             return 0;
  4410         }
  4411 #endif /* FOOTERS */
  4412         return internal_realloc(m, oldmem, bytes);
  4413     }
  4414 }
  4415 
  4416 void *
  4417 dlmemalign(size_t alignment, size_t bytes)
  4418 {
  4419     return internal_memalign(gm, alignment, bytes);
  4420 }
  4421 
  4422 void **
  4423 dlindependent_calloc(size_t n_elements, size_t elem_size, void *chunks[])
  4424 {
  4425     size_t sz = elem_size;      /* serves as 1-element array */
  4426     return ialloc(gm, n_elements, &sz, 3, chunks);
  4427 }
  4428 
  4429 void **
  4430 dlindependent_comalloc(size_t n_elements, size_t sizes[], void *chunks[])
  4431 {
  4432     return ialloc(gm, n_elements, sizes, 0, chunks);
  4433 }
  4434 
  4435 void *
  4436 dlvalloc(size_t bytes)
  4437 {
  4438     size_t pagesz;
  4439     init_mparams();
  4440     pagesz = mparams.page_size;
  4441     return dlmemalign(pagesz, bytes);
  4442 }
  4443 
  4444 void *
  4445 dlpvalloc(size_t bytes)
  4446 {
  4447     size_t pagesz;
  4448     init_mparams();
  4449     pagesz = mparams.page_size;
  4450     return dlmemalign(pagesz,
  4451                       (bytes + pagesz - SIZE_T_ONE) & ~(pagesz - SIZE_T_ONE));
  4452 }
  4453 
  4454 int
  4455 dlmalloc_trim(size_t pad)
  4456 {
  4457     int result = 0;
  4458     if (!PREACTION(gm)) {
  4459         result = sys_trim(gm, pad);
  4460         POSTACTION(gm);
  4461     }
  4462     return result;
  4463 }
  4464 
  4465 size_t
  4466 dlmalloc_footprint(void)
  4467 {
  4468     return gm->footprint;
  4469 }
  4470 
  4471 size_t
  4472 dlmalloc_max_footprint(void)
  4473 {
  4474     return gm->max_footprint;
  4475 }
  4476 
  4477 #if !NO_MALLINFO
  4478 struct mallinfo
  4479 dlmallinfo(void)
  4480 {
  4481     return internal_mallinfo(gm);
  4482 }
  4483 #endif /* NO_MALLINFO */
  4484 
  4485 void
  4486 dlmalloc_stats()
  4487 {
  4488     internal_malloc_stats(gm);
  4489 }
  4490 
  4491 size_t
  4492 dlmalloc_usable_size(void *mem)
  4493 {
  4494     if (mem != 0) {
  4495         mchunkptr p = mem2chunk(mem);
  4496         if (cinuse(p))
  4497             return chunksize(p) - overhead_for(p);
  4498     }
  4499     return 0;
  4500 }
  4501 
  4502 int
  4503 dlmallopt(int param_number, int value)
  4504 {
  4505     return change_mparam(param_number, value);
  4506 }
  4507 
  4508 #endif /* !ONLY_MSPACES */
  4509 
  4510 /* ----------------------------- user mspaces ---------------------------- */
  4511 
  4512 #if MSPACES
  4513 
  4514 static mstate
  4515 init_user_mstate(char *tbase, size_t tsize)
  4516 {
  4517     size_t msize = pad_request(sizeof(struct malloc_state));
  4518     mchunkptr mn;
  4519     mchunkptr msp = align_as_chunk(tbase);
  4520     mstate m = (mstate) (chunk2mem(msp));
  4521     memset(m, 0, msize);
  4522     INITIAL_LOCK(&m->mutex);
  4523     msp->head = (msize | PINUSE_BIT | CINUSE_BIT);
  4524     m->seg.base = m->least_addr = tbase;
  4525     m->seg.size = m->footprint = m->max_footprint = tsize;
  4526     m->magic = mparams.magic;
  4527     m->mflags = mparams.default_mflags;
  4528     disable_contiguous(m);
  4529     init_bins(m);
  4530     mn = next_chunk(mem2chunk(m));
  4531     init_top(m, mn, (size_t) ((tbase + tsize) - (char *) mn) - TOP_FOOT_SIZE);
  4532     check_top_chunk(m, m->top);
  4533     return m;
  4534 }
  4535 
  4536 mspace
  4537 create_mspace(size_t capacity, int locked)
  4538 {
  4539     mstate m = 0;
  4540     size_t msize = pad_request(sizeof(struct malloc_state));
  4541     init_mparams();             /* Ensure pagesize etc initialized */
  4542 
  4543     if (capacity < (size_t) - (msize + TOP_FOOT_SIZE + mparams.page_size)) {
  4544         size_t rs = ((capacity == 0) ? mparams.granularity :
  4545                      (capacity + TOP_FOOT_SIZE + msize));
  4546         size_t tsize = granularity_align(rs);
  4547         char *tbase = (char *) (CALL_MMAP(tsize));
  4548         if (tbase != CMFAIL) {
  4549             m = init_user_mstate(tbase, tsize);
  4550             m->seg.sflags = IS_MMAPPED_BIT;
  4551             set_lock(m, locked);
  4552         }
  4553     }
  4554     return (mspace) m;
  4555 }
  4556 
  4557 mspace
  4558 create_mspace_with_base(void *base, size_t capacity, int locked)
  4559 {
  4560     mstate m = 0;
  4561     size_t msize = pad_request(sizeof(struct malloc_state));
  4562     init_mparams();             /* Ensure pagesize etc initialized */
  4563 
  4564     if (capacity > msize + TOP_FOOT_SIZE &&
  4565         capacity < (size_t) - (msize + TOP_FOOT_SIZE + mparams.page_size)) {
  4566         m = init_user_mstate((char *) base, capacity);
  4567         m->seg.sflags = EXTERN_BIT;
  4568         set_lock(m, locked);
  4569     }
  4570     return (mspace) m;
  4571 }
  4572 
  4573 size_t
  4574 destroy_mspace(mspace msp)
  4575 {
  4576     size_t freed = 0;
  4577     mstate ms = (mstate) msp;
  4578     if (ok_magic(ms)) {
  4579         msegmentptr sp = &ms->seg;
  4580         while (sp != 0) {
  4581             char *base = sp->base;
  4582             size_t size = sp->size;
  4583             flag_t flag = sp->sflags;
  4584             sp = sp->next;
  4585             if ((flag & IS_MMAPPED_BIT) && !(flag & EXTERN_BIT) &&
  4586                 CALL_MUNMAP(base, size) == 0)
  4587                 freed += size;
  4588         }
  4589     } else {
  4590         USAGE_ERROR_ACTION(ms, ms);
  4591     }
  4592     return freed;
  4593 }
  4594 
  4595 /*
  4596   mspace versions of routines are near-clones of the global
  4597   versions. This is not so nice but better than the alternatives.
  4598 */
  4599 
  4600 
  4601 void *
  4602 mspace_malloc(mspace msp, size_t bytes)
  4603 {
  4604     mstate ms = (mstate) msp;
  4605     if (!ok_magic(ms)) {
  4606         USAGE_ERROR_ACTION(ms, ms);
  4607         return 0;
  4608     }
  4609     if (!PREACTION(ms)) {
  4610         void *mem;
  4611         size_t nb;
  4612         if (bytes <= MAX_SMALL_REQUEST) {
  4613             bindex_t idx;
  4614             binmap_t smallbits;
  4615             nb = (bytes < MIN_REQUEST) ? MIN_CHUNK_SIZE : pad_request(bytes);
  4616             idx = small_index(nb);
  4617             smallbits = ms->smallmap >> idx;
  4618 
  4619             if ((smallbits & 0x3U) != 0) {      /* Remainderless fit to a smallbin. */
  4620                 mchunkptr b, p;
  4621                 idx += ~smallbits & 1;  /* Uses next bin if idx empty */
  4622                 b = smallbin_at(ms, idx);
  4623                 p = b->fd;
  4624                 assert(chunksize(p) == small_index2size(idx));
  4625                 unlink_first_small_chunk(ms, b, p, idx);
  4626                 set_inuse_and_pinuse(ms, p, small_index2size(idx));
  4627                 mem = chunk2mem(p);
  4628                 check_malloced_chunk(ms, mem, nb);
  4629                 goto postaction;
  4630             }
  4631 
  4632             else if (nb > ms->dvsize) {
  4633                 if (smallbits != 0) {   /* Use chunk in next nonempty smallbin */
  4634                     mchunkptr b, p, r;
  4635                     size_t rsize;
  4636                     bindex_t i;
  4637                     binmap_t leftbits =
  4638                         (smallbits << idx) & left_bits(idx2bit(idx));
  4639                     binmap_t leastbit = least_bit(leftbits);
  4640                     compute_bit2idx(leastbit, i);
  4641                     b = smallbin_at(ms, i);
  4642                     p = b->fd;
  4643                     assert(chunksize(p) == small_index2size(i));
  4644                     unlink_first_small_chunk(ms, b, p, i);
  4645                     rsize = small_index2size(i) - nb;
  4646                     /* Fit here cannot be remainderless if 4byte sizes */
  4647                     if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
  4648                         set_inuse_and_pinuse(ms, p, small_index2size(i));
  4649                     else {
  4650                         set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
  4651                         r = chunk_plus_offset(p, nb);
  4652                         set_size_and_pinuse_of_free_chunk(r, rsize);
  4653                         replace_dv(ms, r, rsize);
  4654                     }
  4655                     mem = chunk2mem(p);
  4656                     check_malloced_chunk(ms, mem, nb);
  4657                     goto postaction;
  4658                 }
  4659 
  4660                 else if (ms->treemap != 0
  4661                          && (mem = tmalloc_small(ms, nb)) != 0) {
  4662                     check_malloced_chunk(ms, mem, nb);
  4663                     goto postaction;
  4664                 }
  4665             }
  4666         } else if (bytes >= MAX_REQUEST)
  4667             nb = MAX_SIZE_T;    /* Too big to allocate. Force failure (in sys alloc) */
  4668         else {
  4669             nb = pad_request(bytes);
  4670             if (ms->treemap != 0 && (mem = tmalloc_large(ms, nb)) != 0) {
  4671                 check_malloced_chunk(ms, mem, nb);
  4672                 goto postaction;
  4673             }
  4674         }
  4675 
  4676         if (nb <= ms->dvsize) {
  4677             size_t rsize = ms->dvsize - nb;
  4678             mchunkptr p = ms->dv;
  4679             if (rsize >= MIN_CHUNK_SIZE) {      /* split dv */
  4680                 mchunkptr r = ms->dv = chunk_plus_offset(p, nb);
  4681                 ms->dvsize = rsize;
  4682                 set_size_and_pinuse_of_free_chunk(r, rsize);
  4683                 set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
  4684             } else {            /* exhaust dv */
  4685                 size_t dvs = ms->dvsize;
  4686                 ms->dvsize = 0;
  4687                 ms->dv = 0;
  4688                 set_inuse_and_pinuse(ms, p, dvs);
  4689             }
  4690             mem = chunk2mem(p);
  4691             check_malloced_chunk(ms, mem, nb);
  4692             goto postaction;
  4693         }
  4694 
  4695         else if (nb < ms->topsize) {    /* Split top */
  4696             size_t rsize = ms->topsize -= nb;
  4697             mchunkptr p = ms->top;
  4698             mchunkptr r = ms->top = chunk_plus_offset(p, nb);
  4699             r->head = rsize | PINUSE_BIT;
  4700             set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
  4701             mem = chunk2mem(p);
  4702             check_top_chunk(ms, ms->top);
  4703             check_malloced_chunk(ms, mem, nb);
  4704             goto postaction;
  4705         }
  4706 
  4707         mem = sys_alloc(ms, nb);
  4708 
  4709       postaction:
  4710         POSTACTION(ms);
  4711         return mem;
  4712     }
  4713 
  4714     return 0;
  4715 }
  4716 
  4717 void
  4718 mspace_free(mspace msp, void *mem)
  4719 {
  4720     if (mem != 0) {
  4721         mchunkptr p = mem2chunk(mem);
  4722 #if FOOTERS
  4723         mstate fm = get_mstate_for(p);
  4724 #else /* FOOTERS */
  4725         mstate fm = (mstate) msp;
  4726 #endif /* FOOTERS */
  4727         if (!ok_magic(fm)) {
  4728             USAGE_ERROR_ACTION(fm, p);
  4729             return;
  4730         }
  4731         if (!PREACTION(fm)) {
  4732             check_inuse_chunk(fm, p);
  4733             if (RTCHECK(ok_address(fm, p) && ok_cinuse(p))) {
  4734                 size_t psize = chunksize(p);
  4735                 mchunkptr next = chunk_plus_offset(p, psize);
  4736                 if (!pinuse(p)) {
  4737                     size_t prevsize = p->prev_foot;
  4738                     if ((prevsize & IS_MMAPPED_BIT) != 0) {
  4739                         prevsize &= ~IS_MMAPPED_BIT;
  4740                         psize += prevsize + MMAP_FOOT_PAD;
  4741                         if (CALL_MUNMAP((char *) p - prevsize, psize) == 0)
  4742                             fm->footprint -= psize;
  4743                         goto postaction;
  4744                     } else {
  4745                         mchunkptr prev = chunk_minus_offset(p, prevsize);
  4746                         psize += prevsize;
  4747                         p = prev;
  4748                         if (RTCHECK(ok_address(fm, prev))) {    /* consolidate backward */
  4749                             if (p != fm->dv) {
  4750                                 unlink_chunk(fm, p, prevsize);
  4751                             } else if ((next->head & INUSE_BITS) ==
  4752                                        INUSE_BITS) {
  4753                                 fm->dvsize = psize;
  4754                                 set_free_with_pinuse(p, psize, next);
  4755                                 goto postaction;
  4756                             }
  4757                         } else
  4758                             goto erroraction;
  4759                     }
  4760                 }
  4761 
  4762                 if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
  4763                     if (!cinuse(next)) {        /* consolidate forward */
  4764                         if (next == fm->top) {
  4765                             size_t tsize = fm->topsize += psize;
  4766                             fm->top = p;
  4767                             p->head = tsize | PINUSE_BIT;
  4768                             if (p == fm->dv) {
  4769                                 fm->dv = 0;
  4770                                 fm->dvsize = 0;
  4771                             }
  4772                             if (should_trim(fm, tsize))
  4773                                 sys_trim(fm, 0);
  4774                             goto postaction;
  4775                         } else if (next == fm->dv) {
  4776                             size_t dsize = fm->dvsize += psize;
  4777                             fm->dv = p;
  4778                             set_size_and_pinuse_of_free_chunk(p, dsize);
  4779                             goto postaction;
  4780                         } else {
  4781                             size_t nsize = chunksize(next);
  4782                             psize += nsize;
  4783                             unlink_chunk(fm, next, nsize);
  4784                             set_size_and_pinuse_of_free_chunk(p, psize);
  4785                             if (p == fm->dv) {
  4786                                 fm->dvsize = psize;
  4787                                 goto postaction;
  4788                             }
  4789                         }
  4790                     } else
  4791                         set_free_with_pinuse(p, psize, next);
  4792                     insert_chunk(fm, p, psize);
  4793                     check_free_chunk(fm, p);
  4794                     goto postaction;
  4795                 }
  4796             }
  4797           erroraction:
  4798             USAGE_ERROR_ACTION(fm, p);
  4799           postaction:
  4800             POSTACTION(fm);
  4801         }
  4802     }
  4803 }
  4804 
  4805 void *
  4806 mspace_calloc(mspace msp, size_t n_elements, size_t elem_size)
  4807 {
  4808     void *mem;
  4809     size_t req = 0;
  4810     mstate ms = (mstate) msp;
  4811     if (!ok_magic(ms)) {
  4812         USAGE_ERROR_ACTION(ms, ms);
  4813         return 0;
  4814     }
  4815     if (n_elements != 0) {
  4816         req = n_elements * elem_size;
  4817         if (((n_elements | elem_size) & ~(size_t) 0xffff) &&
  4818             (req / n_elements != elem_size))
  4819             req = MAX_SIZE_T;   /* force downstream failure on overflow */
  4820     }
  4821     mem = internal_malloc(ms, req);
  4822     if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
  4823         memset(mem, 0, req);
  4824     return mem;
  4825 }
  4826 
  4827 void *
  4828 mspace_realloc(mspace msp, void *oldmem, size_t bytes)
  4829 {
  4830     if (oldmem == 0)
  4831         return mspace_malloc(msp, bytes);
  4832 #ifdef REALLOC_ZERO_BYTES_FREES
  4833     if (bytes == 0) {
  4834         mspace_free(msp, oldmem);
  4835         return 0;
  4836     }
  4837 #endif /* REALLOC_ZERO_BYTES_FREES */
  4838     else {
  4839 #if FOOTERS
  4840         mchunkptr p = mem2chunk(oldmem);
  4841         mstate ms = get_mstate_for(p);
  4842 #else /* FOOTERS */
  4843         mstate ms = (mstate) msp;
  4844 #endif /* FOOTERS */
  4845         if (!ok_magic(ms)) {
  4846             USAGE_ERROR_ACTION(ms, ms);
  4847             return 0;
  4848         }
  4849         return internal_realloc(ms, oldmem, bytes);
  4850     }
  4851 }
  4852 
  4853 void *
  4854 mspace_memalign(mspace msp, size_t alignment, size_t bytes)
  4855 {
  4856     mstate ms = (mstate) msp;
  4857     if (!ok_magic(ms)) {
  4858         USAGE_ERROR_ACTION(ms, ms);
  4859         return 0;
  4860     }
  4861     return internal_memalign(ms, alignment, bytes);
  4862 }
  4863 
  4864 void **
  4865 mspace_independent_calloc(mspace msp, size_t n_elements,
  4866                           size_t elem_size, void *chunks[])
  4867 {
  4868     size_t sz = elem_size;      /* serves as 1-element array */
  4869     mstate ms = (mstate) msp;
  4870     if (!ok_magic(ms)) {
  4871         USAGE_ERROR_ACTION(ms, ms);
  4872         return 0;
  4873     }
  4874     return ialloc(ms, n_elements, &sz, 3, chunks);
  4875 }
  4876 
  4877 void **
  4878 mspace_independent_comalloc(mspace msp, size_t n_elements,
  4879                             size_t sizes[], void *chunks[])
  4880 {
  4881     mstate ms = (mstate) msp;
  4882     if (!ok_magic(ms)) {
  4883         USAGE_ERROR_ACTION(ms, ms);
  4884         return 0;
  4885     }
  4886     return ialloc(ms, n_elements, sizes, 0, chunks);
  4887 }
  4888 
  4889 int
  4890 mspace_trim(mspace msp, size_t pad)
  4891 {
  4892     int result = 0;
  4893     mstate ms = (mstate) msp;
  4894     if (ok_magic(ms)) {
  4895         if (!PREACTION(ms)) {
  4896             result = sys_trim(ms, pad);
  4897             POSTACTION(ms);
  4898         }
  4899     } else {
  4900         USAGE_ERROR_ACTION(ms, ms);
  4901     }
  4902     return result;
  4903 }
  4904 
  4905 void
  4906 mspace_malloc_stats(mspace msp)
  4907 {
  4908     mstate ms = (mstate) msp;
  4909     if (ok_magic(ms)) {
  4910         internal_malloc_stats(ms);
  4911     } else {
  4912         USAGE_ERROR_ACTION(ms, ms);
  4913     }
  4914 }
  4915 
  4916 size_t
  4917 mspace_footprint(mspace msp)
  4918 {
  4919     size_t result;
  4920     mstate ms = (mstate) msp;
  4921     if (ok_magic(ms)) {
  4922         result = ms->footprint;
  4923     }
  4924     USAGE_ERROR_ACTION(ms, ms);
  4925     return result;
  4926 }
  4927 
  4928 
  4929 size_t
  4930 mspace_max_footprint(mspace msp)
  4931 {
  4932     size_t result;
  4933     mstate ms = (mstate) msp;
  4934     if (ok_magic(ms)) {
  4935         result = ms->max_footprint;
  4936     }
  4937     USAGE_ERROR_ACTION(ms, ms);
  4938     return result;
  4939 }
  4940 
  4941 
  4942 #if !NO_MALLINFO
  4943 struct mallinfo
  4944 mspace_mallinfo(mspace msp)
  4945 {
  4946     mstate ms = (mstate) msp;
  4947     if (!ok_magic(ms)) {
  4948         USAGE_ERROR_ACTION(ms, ms);
  4949     }
  4950     return internal_mallinfo(ms);
  4951 }
  4952 #endif /* NO_MALLINFO */
  4953 
  4954 int
  4955 mspace_mallopt(int param_number, int value)
  4956 {
  4957     return change_mparam(param_number, value);
  4958 }
  4959 
  4960 #endif /* MSPACES */
  4961 
  4962 /* -------------------- Alternative MORECORE functions ------------------- */
  4963 
  4964 /*
  4965   Guidelines for creating a custom version of MORECORE:
  4966 
  4967   * For best performance, MORECORE should allocate in multiples of pagesize.
  4968   * MORECORE may allocate more memory than requested. (Or even less,
  4969       but this will usually result in a malloc failure.)
  4970   * MORECORE must not allocate memory when given argument zero, but
  4971       instead return one past the end address of memory from previous
  4972       nonzero call.
  4973   * For best performance, consecutive calls to MORECORE with positive
  4974       arguments should return increasing addresses, indicating that
  4975       space has been contiguously extended.
  4976   * Even though consecutive calls to MORECORE need not return contiguous
  4977       addresses, it must be OK for malloc'ed chunks to span multiple
  4978       regions in those cases where they do happen to be contiguous.
  4979   * MORECORE need not handle negative arguments -- it may instead
  4980       just return MFAIL when given negative arguments.
  4981       Negative arguments are always multiples of pagesize. MORECORE
  4982       must not misinterpret negative args as large positive unsigned
  4983       args. You can suppress all such calls from even occurring by defining
  4984       MORECORE_CANNOT_TRIM,
  4985 
  4986   As an example alternative MORECORE, here is a custom allocator
  4987   kindly contributed for pre-OSX macOS.  It uses virtually but not
  4988   necessarily physically contiguous non-paged memory (locked in,
  4989   present and won't get swapped out).  You can use it by uncommenting
  4990   this section, adding some #includes, and setting up the appropriate
  4991   defines above:
  4992 
  4993       #define MORECORE osMoreCore
  4994 
  4995   There is also a shutdown routine that should somehow be called for
  4996   cleanup upon program exit.
  4997 
  4998   #define MAX_POOL_ENTRIES 100
  4999   #define MINIMUM_MORECORE_SIZE  (64 * 1024U)
  5000   static int next_os_pool;
  5001   void *our_os_pools[MAX_POOL_ENTRIES];
  5002 
  5003   void *osMoreCore(int size)
  5004   {
  5005     void *ptr = 0;
  5006     static void *sbrk_top = 0;
  5007 
  5008     if (size > 0)
  5009     {
  5010       if (size < MINIMUM_MORECORE_SIZE)
  5011          size = MINIMUM_MORECORE_SIZE;
  5012       if (CurrentExecutionLevel() == kTaskLevel)
  5013          ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
  5014       if (ptr == 0)
  5015       {
  5016         return (void *) MFAIL;
  5017       }
  5018       // save ptrs so they can be freed during cleanup
  5019       our_os_pools[next_os_pool] = ptr;
  5020       next_os_pool++;
  5021       ptr = (void *) ((((size_t) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
  5022       sbrk_top = (char *) ptr + size;
  5023       return ptr;
  5024     }
  5025     else if (size < 0)
  5026     {
  5027       // we don't currently support shrink behavior
  5028       return (void *) MFAIL;
  5029     }
  5030     else
  5031     {
  5032       return sbrk_top;
  5033     }
  5034   }
  5035 
  5036   // cleanup any allocated memory pools
  5037   // called as last thing before shutting down driver
  5038 
  5039   void osCleanupMem(void)
  5040   {
  5041     void **ptr;
  5042 
  5043     for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
  5044       if (*ptr)
  5045       {
  5046          PoolDeallocate(*ptr);
  5047          *ptr = 0;
  5048       }
  5049   }
  5050 
  5051 */
  5052 
  5053 
  5054 /* -----------------------------------------------------------------------
  5055 History:
  5056     V2.8.3 Thu Sep 22 11:16:32 2005  Doug Lea  (dl at gee)
  5057       * Add max_footprint functions
  5058       * Ensure all appropriate literals are size_t
  5059       * Fix conditional compilation problem for some #define settings
  5060       * Avoid concatenating segments with the one provided
  5061         in create_mspace_with_base
  5062       * Rename some variables to avoid compiler shadowing warnings
  5063       * Use explicit lock initialization.
  5064       * Better handling of sbrk interference.
  5065       * Simplify and fix segment insertion, trimming and mspace_destroy
  5066       * Reinstate REALLOC_ZERO_BYTES_FREES option from 2.7.x
  5067       * Thanks especially to Dennis Flanagan for help on these.
  5068 
  5069     V2.8.2 Sun Jun 12 16:01:10 2005  Doug Lea  (dl at gee)
  5070       * Fix memalign brace error.
  5071 
  5072     V2.8.1 Wed Jun  8 16:11:46 2005  Doug Lea  (dl at gee)
  5073       * Fix improper #endif nesting in C++
  5074       * Add explicit casts needed for C++
  5075 
  5076     V2.8.0 Mon May 30 14:09:02 2005  Doug Lea  (dl at gee)
  5077       * Use trees for large bins
  5078       * Support mspaces
  5079       * Use segments to unify sbrk-based and mmap-based system allocation,
  5080         removing need for emulation on most platforms without sbrk.
  5081       * Default safety checks
  5082       * Optional footer checks. Thanks to William Robertson for the idea.
  5083       * Internal code refactoring
  5084       * Incorporate suggestions and platform-specific changes.
  5085         Thanks to Dennis Flanagan, Colin Plumb, Niall Douglas,
  5086         Aaron Bachmann,  Emery Berger, and others.
  5087       * Speed up non-fastbin processing enough to remove fastbins.
  5088       * Remove useless cfree() to avoid conflicts with other apps.
  5089       * Remove internal memcpy, memset. Compilers handle builtins better.
  5090       * Remove some options that no one ever used and rename others.
  5091 
  5092     V2.7.2 Sat Aug 17 09:07:30 2002  Doug Lea  (dl at gee)
  5093       * Fix malloc_state bitmap array misdeclaration
  5094 
  5095     V2.7.1 Thu Jul 25 10:58:03 2002  Doug Lea  (dl at gee)
  5096       * Allow tuning of FIRST_SORTED_BIN_SIZE
  5097       * Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte.
  5098       * Better detection and support for non-contiguousness of MORECORE.
  5099         Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger
  5100       * Bypass most of malloc if no frees. Thanks To Emery Berger.
  5101       * Fix freeing of old top non-contiguous chunk im sysmalloc.
  5102       * Raised default trim and map thresholds to 256K.
  5103       * Fix mmap-related #defines. Thanks to Lubos Lunak.
  5104       * Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield.
  5105       * Branch-free bin calculation
  5106       * Default trim and mmap thresholds now 256K.
  5107 
  5108     V2.7.0 Sun Mar 11 14:14:06 2001  Doug Lea  (dl at gee)
  5109       * Introduce independent_comalloc and independent_calloc.
  5110         Thanks to Michael Pachos for motivation and help.
  5111       * Make optional .h file available
  5112       * Allow > 2GB requests on 32bit systems.
  5113       * new WIN32 sbrk, mmap, munmap, lock code from <Walter@GeNeSys-e.de>.
  5114         Thanks also to Andreas Mueller <a.mueller at paradatec.de>,
  5115         and Anonymous.
  5116       * Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for
  5117         helping test this.)
  5118       * memalign: check alignment arg
  5119       * realloc: don't try to shift chunks backwards, since this
  5120         leads to  more fragmentation in some programs and doesn't
  5121         seem to help in any others.
  5122       * Collect all cases in malloc requiring system memory into sysmalloc
  5123       * Use mmap as backup to sbrk
  5124       * Place all internal state in malloc_state
  5125       * Introduce fastbins (although similar to 2.5.1)
  5126       * Many minor tunings and cosmetic improvements
  5127       * Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK
  5128       * Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
  5129         Thanks to Tony E. Bennett <tbennett@nvidia.com> and others.
  5130       * Include errno.h to support default failure action.
  5131 
  5132     V2.6.6 Sun Dec  5 07:42:19 1999  Doug Lea  (dl at gee)
  5133       * return null for negative arguments
  5134       * Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
  5135          * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
  5136           (e.g. WIN32 platforms)
  5137          * Cleanup header file inclusion for WIN32 platforms
  5138          * Cleanup code to avoid Microsoft Visual C++ compiler complaints
  5139          * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
  5140            memory allocation routines
  5141          * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
  5142          * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
  5143            usage of 'assert' in non-WIN32 code
  5144          * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
  5145            avoid infinite loop
  5146       * Always call 'fREe()' rather than 'free()'
  5147 
  5148     V2.6.5 Wed Jun 17 15:57:31 1998  Doug Lea  (dl at gee)
  5149       * Fixed ordering problem with boundary-stamping
  5150 
  5151     V2.6.3 Sun May 19 08:17:58 1996  Doug Lea  (dl at gee)
  5152       * Added pvalloc, as recommended by H.J. Liu
  5153       * Added 64bit pointer support mainly from Wolfram Gloger
  5154       * Added anonymously donated WIN32 sbrk emulation
  5155       * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
  5156       * malloc_extend_top: fix mask error that caused wastage after
  5157         foreign sbrks
  5158       * Add linux mremap support code from HJ Liu
  5159 
  5160     V2.6.2 Tue Dec  5 06:52:55 1995  Doug Lea  (dl at gee)
  5161       * Integrated most documentation with the code.
  5162       * Add support for mmap, with help from
  5163         Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
  5164       * Use last_remainder in more cases.
  5165       * Pack bins using idea from  colin@nyx10.cs.du.edu
  5166       * Use ordered bins instead of best-fit threshhold
  5167       * Eliminate block-local decls to simplify tracing and debugging.
  5168       * Support another case of realloc via move into top
  5169       * Fix error occuring when initial sbrk_base not word-aligned.
  5170       * Rely on page size for units instead of SBRK_UNIT to
  5171         avoid surprises about sbrk alignment conventions.
  5172       * Add mallinfo, mallopt. Thanks to Raymond Nijssen
  5173         (raymond@es.ele.tue.nl) for the suggestion.
  5174       * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
  5175       * More precautions for cases where other routines call sbrk,
  5176         courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
  5177       * Added macros etc., allowing use in linux libc from
  5178         H.J. Lu (hjl@gnu.ai.mit.edu)
  5179       * Inverted this history list
  5180 
  5181     V2.6.1 Sat Dec  2 14:10:57 1995  Doug Lea  (dl at gee)
  5182       * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
  5183       * Removed all preallocation code since under current scheme
  5184         the work required to undo bad preallocations exceeds
  5185         the work saved in good cases for most test programs.
  5186       * No longer use return list or unconsolidated bins since
  5187         no scheme using them consistently outperforms those that don't
  5188         given above changes.
  5189       * Use best fit for very large chunks to prevent some worst-cases.
  5190       * Added some support for debugging
  5191 
  5192     V2.6.0 Sat Nov  4 07:05:23 1995  Doug Lea  (dl at gee)
  5193       * Removed footers when chunks are in use. Thanks to
  5194         Paul Wilson (wilson@cs.texas.edu) for the suggestion.
  5195 
  5196     V2.5.4 Wed Nov  1 07:54:51 1995  Doug Lea  (dl at gee)
  5197       * Added malloc_trim, with help from Wolfram Gloger
  5198         (wmglo@Dent.MED.Uni-Muenchen.DE).
  5199 
  5200     V2.5.3 Tue Apr 26 10:16:01 1994  Doug Lea  (dl at g)
  5201 
  5202     V2.5.2 Tue Apr  5 16:20:40 1994  Doug Lea  (dl at g)
  5203       * realloc: try to expand in both directions
  5204       * malloc: swap order of clean-bin strategy;
  5205       * realloc: only conditionally expand backwards
  5206       * Try not to scavenge used bins
  5207       * Use bin counts as a guide to preallocation
  5208       * Occasionally bin return list chunks in first scan
  5209       * Add a few optimizations from colin@nyx10.cs.du.edu
  5210 
  5211     V2.5.1 Sat Aug 14 15:40:43 1993  Doug Lea  (dl at g)
  5212       * faster bin computation & slightly different binning
  5213       * merged all consolidations to one part of malloc proper
  5214          (eliminating old malloc_find_space & malloc_clean_bin)
  5215       * Scan 2 returns chunks (not just 1)
  5216       * Propagate failure in realloc if malloc returns 0
  5217       * Add stuff to allow compilation on non-ANSI compilers
  5218           from kpv@research.att.com
  5219 
  5220     V2.5 Sat Aug  7 07:41:59 1993  Doug Lea  (dl at g.oswego.edu)
  5221       * removed potential for odd address access in prev_chunk
  5222       * removed dependency on getpagesize.h
  5223       * misc cosmetics and a bit more internal documentation
  5224       * anticosmetics: mangled names in macros to evade debugger strangeness
  5225       * tested on sparc, hp-700, dec-mips, rs6000
  5226           with gcc & native cc (hp, dec only) allowing
  5227           Detlefs & Zorn comparison study (in SIGPLAN Notices.)
  5228 
  5229     Trial version Fri Aug 28 13:14:29 1992  Doug Lea  (dl at g.oswego.edu)
  5230       * Based loosely on libg++-1.2X malloc. (It retains some of the overall
  5231          structure of old version,  but most details differ.)
  5232  
  5233 */
  5234 
  5235 #endif /* !HAVE_MALLOC */
  5236 /* vi: set ts=4 sw=4 expandtab: */