include/SDL_rwops.h
author Sam Lantinga <slouken@libsdl.org>
Tue, 10 Jul 2007 05:01:22 +0000
changeset 2159 dd4753e47ed4
parent 1895 c121d94672cb
child 2160 00adbaed3910
permissions -rw-r--r--
Merged read-ahead support for Win32 file I/O from SDL 1.2 revision 3183
     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 
    23 /**
    24  * \file SDL_rwops.h
    25  *
    26  * This file provides a general interface for SDL to read and write
    27  * data sources.  It can easily be extended to files, memory, etc.
    28  */
    29 
    30 #ifndef _SDL_rwops_h
    31 #define _SDL_rwops_h
    32 
    33 #include "SDL_stdinc.h"
    34 #include "SDL_error.h"
    35 
    36 #include "begin_code.h"
    37 /* Set up for C function definitions, even when using C++ */
    38 #ifdef __cplusplus
    39 /* *INDENT-OFF* */
    40 extern "C" {
    41 /* *INDENT-ON* */
    42 #endif
    43 
    44 /* This is the read/write operation structure -- very basic */
    45 
    46 typedef struct SDL_RWops
    47 {
    48     /* Seek to 'offset' relative to whence, one of stdio's whence values:
    49        SEEK_SET, SEEK_CUR, SEEK_END
    50        Returns the final offset in the data source.
    51      */
    52     int (SDLCALL * seek) (struct SDL_RWops * context, int offset, int whence);
    53 
    54     /* Read up to 'num' objects each of size 'objsize' from the data
    55        source to the area pointed at by 'ptr'.
    56        Returns the number of objects read, or -1 if the read failed.
    57      */
    58     int (SDLCALL * read) (struct SDL_RWops * context, void *ptr, int size,
    59                           int maxnum);
    60 
    61     /* Write exactly 'num' objects each of size 'objsize' from the area
    62        pointed at by 'ptr' to data source.
    63        Returns 'num', or -1 if the write failed.
    64      */
    65     int (SDLCALL * write) (struct SDL_RWops * context, const void *ptr,
    66                            int size, int num);
    67 
    68     /* Close and free an allocated SDL_FSops structure */
    69     int (SDLCALL * close) (struct SDL_RWops * context);
    70 
    71     Uint32 type;
    72     union
    73     {
    74 #ifdef __WIN32__
    75         struct
    76         {
    77             int append;
    78             void *h;
    79             struct
    80             {
    81                 void *data;
    82                 int size;
    83                 int left;
    84             } buffer;
    85         } win32io;
    86 #endif
    87 #ifdef HAVE_STDIO_H
    88         struct
    89         {
    90             int autoclose;
    91             FILE *fp;
    92         } stdio;
    93 #endif
    94         struct
    95         {
    96             Uint8 *base;
    97             Uint8 *here;
    98             Uint8 *stop;
    99         } mem;
   100         struct
   101         {
   102             void *data1;
   103         } unknown;
   104     } hidden;
   105 
   106 } SDL_RWops;
   107 
   108 
   109 /* Functions to create SDL_RWops structures from various data sources */
   110 
   111 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFile(const char *file,
   112                                                   const char *mode);
   113 
   114 #ifdef HAVE_STDIO_H
   115 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFP(FILE * fp, int autoclose);
   116 #endif
   117 
   118 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromMem(void *mem, int size);
   119 extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromConstMem(const void *mem,
   120                                                       int size);
   121 
   122 extern DECLSPEC SDL_RWops *SDLCALL SDL_AllocRW(void);
   123 extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops * area);
   124 
   125 #define RW_SEEK_SET	0       /* Seek from the beginning of data */
   126 #define RW_SEEK_CUR	1       /* Seek relative to current read point */
   127 #define RW_SEEK_END	2       /* Seek relative to the end of data */
   128 
   129 /* Macros to easily read and write from an SDL_RWops structure */
   130 #define SDL_RWseek(ctx, offset, whence)	(ctx)->seek(ctx, offset, whence)
   131 #define SDL_RWtell(ctx)			(ctx)->seek(ctx, 0, RW_SEEK_CUR)
   132 #define SDL_RWread(ctx, ptr, size, n)	(ctx)->read(ctx, ptr, size, n)
   133 #define SDL_RWwrite(ctx, ptr, size, n)	(ctx)->write(ctx, ptr, size, n)
   134 #define SDL_RWclose(ctx)		(ctx)->close(ctx)
   135 
   136 
   137 /* Read an item of the specified endianness and return in native format */
   138 extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops * src);
   139 extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops * src);
   140 extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops * src);
   141 extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops * src);
   142 extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops * src);
   143 extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops * src);
   144 
   145 /* Write an item of native format to the specified endianness */
   146 extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops * dst, Uint16 value);
   147 extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops * dst, Uint16 value);
   148 extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops * dst, Uint32 value);
   149 extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops * dst, Uint32 value);
   150 extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops * dst, Uint64 value);
   151 extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops * dst, Uint64 value);
   152 
   153 
   154 /* Ends C function definitions when using C++ */
   155 #ifdef __cplusplus
   156 /* *INDENT-OFF* */
   157 }
   158 /* *INDENT-ON* */
   159 #endif
   160 #include "close_code.h"
   161 
   162 #endif /* _SDL_rwops_h */
   163 
   164 /* vi: set ts=4 sw=4 expandtab: */