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  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.  
  23. /** @file SDL_rwops.h
  24.  *  This file provides a general interface for SDL to read and write
  25.  *  data sources.  It can easily be extended to files, memory, etc.
  26.  */
  27.  
  28. #ifndef _SDL_rwops_h
  29. #define _SDL_rwops_h
  30.  
  31. #include "SDL_stdinc.h"
  32. #include "SDL_error.h"
  33.  
  34. #include "begin_code.h"
  35. /* Set up for C function definitions, even when using C++ */
  36. #ifdef __cplusplus
  37. extern "C" {
  38. #endif
  39.  
  40. /** This is the read/write operation structure -- very basic */
  41.  
  42. typedef struct SDL_RWops {
  43.         /** Seek to 'offset' relative to whence, one of stdio's whence values:
  44.          *      SEEK_SET, SEEK_CUR, SEEK_END
  45.          *  Returns the final offset in the data source.
  46.          */
  47.         int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);
  48.  
  49.         /** Read up to 'maxnum' objects each of size 'size' from the data
  50.          *  source to the area pointed at by 'ptr'.
  51.          *  Returns the number of objects read, or -1 if the read failed.
  52.          */
  53.         int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
  54.  
  55.         /** Write exactly 'num' objects each of size 'objsize' from the area
  56.          *  pointed at by 'ptr' to data source.
  57.          *  Returns 'num', or -1 if the write failed.
  58.          */
  59.         int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);
  60.  
  61.         /** Close and free an allocated SDL_FSops structure */
  62.         int (SDLCALL *close)(struct SDL_RWops *context);
  63.  
  64.         Uint32 type;
  65.         union {
  66. #if defined(__WIN32__) && !defined(__SYMBIAN32__)
  67.             struct {
  68.                 int   append;
  69.                 void *h;
  70.                 struct {
  71.                     void *data;
  72.                     int size;
  73.                     int left;
  74.                 } buffer;
  75.             } win32io;
  76. #endif
  77. #ifdef HAVE_STDIO_H
  78.             struct {
  79.                 int autoclose;
  80.                 FILE *fp;
  81.             } stdio;
  82. #endif
  83.             struct {
  84.                 Uint8 *base;
  85.                 Uint8 *here;
  86.                 Uint8 *stop;
  87.             } mem;
  88.             struct {
  89.                 void *data1;
  90.             } unknown;
  91.         } hidden;
  92.  
  93. } SDL_RWops;
  94.  
  95.  
  96. /** @name Functions to create SDL_RWops structures from various data sources */
  97. /*@{*/
  98.  
  99. extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);
  100.  
  101. #ifdef HAVE_STDIO_H
  102. extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
  103. #endif
  104.  
  105. extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);
  106. extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromConstMem(const void *mem, int size);
  107.  
  108. extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
  109. extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
  110.  
  111. /*@}*/
  112.  
  113. /** @name Seek Reference Points */
  114. /*@{*/
  115. #define RW_SEEK_SET     0       /**< Seek from the beginning of data */
  116. #define RW_SEEK_CUR     1       /**< Seek relative to current read point */
  117. #define RW_SEEK_END     2       /**< Seek relative to the end of data */
  118. /*@}*/
  119.  
  120. /** @name Macros to easily read and write from an SDL_RWops structure */
  121. /*@{*/
  122. #define SDL_RWseek(ctx, offset, whence) (ctx)->seek(ctx, offset, whence)
  123. #define SDL_RWtell(ctx)                 (ctx)->seek(ctx, 0, RW_SEEK_CUR)
  124. #define SDL_RWread(ctx, ptr, size, n)   (ctx)->read(ctx, ptr, size, n)
  125. #define SDL_RWwrite(ctx, ptr, size, n)  (ctx)->write(ctx, ptr, size, n)
  126. #define SDL_RWclose(ctx)                (ctx)->close(ctx)
  127. /*@}*/
  128.  
  129. /** @name Read an item of the specified endianness and return in native format */
  130. /*@{*/
  131. extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops *src);
  132. extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops *src);
  133. extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops *src);
  134. extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops *src);
  135. extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops *src);
  136. extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops *src);
  137. /*@}*/
  138.  
  139. /** @name Write an item of native format to the specified endianness */
  140. /*@{*/
  141. extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
  142. extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
  143. extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
  144. extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
  145. extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
  146. extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
  147. /*@}*/
  148.  
  149. /* Ends C function definitions when using C++ */
  150. #ifdef __cplusplus
  151. }
  152. #endif
  153. #include "close_code.h"
  154.  
  155. #endif /* _SDL_rwops_h */
  156.