include/SDL_assert.h
changeset 3647 c5925cd41955
child 3649 1e74d7984d0b
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3646:88235d40b135 3647:c5925cd41955
       
     1 /*
       
     2     SDL - Simple DirectMedia Layer
       
     3     Copyright (C) 1997-2009 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 is an assert macro for SDL's internal use. Not for the public API! */
       
    25 
       
    26 #ifndef _SDL_assert_h
       
    27 #define _SDL_assert_h
       
    28 
       
    29 #ifndef SDL_ASSERT_LEVEL
       
    30 #error SDL_ASSERT_LEVEL is not defined. Please fix your SDL_config.h.
       
    31 #endif
       
    32 
       
    33 /*
       
    34 sizeof (x) makes the compiler still parse the expression even without
       
    35 assertions enabled, so the code is always checked at compile time, but
       
    36 doesn't actually generate code for it, so there are no side effects or
       
    37 expensive checks at run time, just the constant size of what x WOULD be,
       
    38 which presumably gets optimized out as unused.
       
    39 This also solves the problem of...
       
    40 
       
    41     int somevalue = blah();
       
    42     SDL_assert(somevalue == 1);
       
    43 
       
    44 ...which would cause compiles to complain that somevalue is unused if we
       
    45 disable assertions.
       
    46 */
       
    47 
       
    48 #define SDL_disabled_assert(condition) \
       
    49     do { (void) sizeof ((condition)); } while (0)
       
    50 
       
    51 #if (SDL_ASSERT_LEVEL > 0)
       
    52 
       
    53 /*
       
    54 These are macros and not first class functions so that the debugger breaks
       
    55 on the assertion line and not in some random guts of SDL, and so each
       
    56 macro can have unique static variables associated with it.
       
    57 */
       
    58 
       
    59 #if (defined(_MSC_VER) && ((_M_IX86) || (_M_X64)))
       
    60     #define SDL_TriggerBreakpoint() __asm { int 3 }
       
    61 #elif (defined(__GNUC__) && ((__i386__) || (__x86_64__)))
       
    62     #define SDL_TriggerBreakpoint() __asm__ __volatile__ ( "int $3\n\t" )
       
    63 #elif defined(unix)
       
    64     #include <signal.h>
       
    65     #define SDL_TriggerBreakpoint() raise(SIGTRAP)
       
    66 #else
       
    67     #error Please define your platform or set SDL_ASSERT_LEVEL to 0.
       
    68 #endif
       
    69 
       
    70 #if (__STDC_VERSION__ >= 199901L) /* C99 supports __func__ as a standard. */
       
    71 #   define SDL_FUNCTION __func__
       
    72 #elif ((__GNUC__ >= 2) || defined(_MSC_VER))
       
    73 #   define SDL_FUNCTION __FUNCTION__
       
    74 #else
       
    75 #   define SDL_FUNCTION "???"
       
    76 #endif
       
    77 
       
    78 typedef enum
       
    79 {
       
    80     SDL_ASSERTION_RETRY,  /**< Retry the assert immediately. */
       
    81     SDL_ASSERTION_BREAK,  /**< Make the debugger trigger a breakpoint. */
       
    82     SDL_ASSERTION_ABORT,  /**< Terminate the program. */
       
    83     SDL_ASSERTION_IGNORE,  /**< Ignore the assert. */
       
    84     SDL_ASSERTION_ALWAYS_IGNORE,  /**< Ignore the assert from now on. */
       
    85 } SDL_assert_state;
       
    86 
       
    87 typedef struct SDL_assert_data
       
    88 {
       
    89     int always_ignore;
       
    90     unsigned int trigger_count;
       
    91     const char *condition;
       
    92     const char *filename;
       
    93     int linenum;
       
    94     const char *function;
       
    95     struct SDL_assert_data *next;
       
    96 } SDL_assert_data;
       
    97 
       
    98 SDL_assert_state SDL_ReportAssertion(SDL_assert_data *, const char *, int);
       
    99 
       
   100 /* the do {} while(0) avoids dangling else problems:
       
   101     if (x) SDL_assert(y); else blah();
       
   102        ... without the do/while, the "else" could attach to this macro's "if".
       
   103    We try to handle just the minimum we need here in a macro...the loop,
       
   104    the static vars, and break points. The heavy lifting is handled in
       
   105    SDL_ReportAssertion(), in SDL_assert.c.
       
   106 */
       
   107 #define SDL_enabled_assert(condition) \
       
   108     do { \
       
   109         while ( !(condition) ) { \
       
   110 			static struct SDL_assert_data assert_data = { \
       
   111                 0, 0, #condition, __FILE__, 0, 0, 0 \
       
   112             }; \
       
   113 			const SDL_assert_state state = SDL_ReportAssertion(&assert_data, \
       
   114                                                                SDL_FUNCTION, \
       
   115 															   __LINE__); \
       
   116             if (state == SDL_ASSERTION_RETRY) { \
       
   117                 continue; /* go again. */ \
       
   118             } else if (state == SDL_ASSERTION_BREAK) { \
       
   119                 SDL_TriggerBreakpoint(); \
       
   120             } \
       
   121             break; /* not retrying. */ \
       
   122         } \
       
   123     } while (0)
       
   124 
       
   125 #endif  /* enabled assertions support code */
       
   126 
       
   127 /* Enable various levels of assertions. */
       
   128 #if SDL_ASSERT_LEVEL == 0   /* assertions disabled */
       
   129 #   define SDL_assert(condition) SDL_disabled_assert(condition)
       
   130 #   define SDL_assert_release(condition) SDL_disabled_assert(condition)
       
   131 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
       
   132 #elif SDL_ASSERT_LEVEL == 1  /* release settings. */
       
   133 #   define SDL_assert(condition) SDL_enabled_assert(condition)
       
   134 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
       
   135 #   define SDL_assert_paranoid(condition) SDL_enabled_assert(condition)
       
   136 #elif SDL_ASSERT_LEVEL == 2  /* normal settings. */
       
   137 #   define SDL_assert(condition) SDL_enabled_assert(condition)
       
   138 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
       
   139 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
       
   140 #elif SDL_ASSERT_LEVEL == 3  /* paranoid settings. */
       
   141 #   define SDL_assert(condition) SDL_enabled_assert(condition)
       
   142 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
       
   143 #   define SDL_assert_paranoid(condition) SDL_enabled_assert(condition)
       
   144 #else
       
   145 #   error Unknown assertion level. Please fix your SDL_config.h.
       
   146 #endif
       
   147 
       
   148 #endif /* _SDL_assert_h */
       
   149 
       
   150 /* vi: set ts=4 sw=4 expandtab: */
       
   151