include/SDL_rwops.h

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