2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2009 Sam Lantinga
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.
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.
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
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.
31 #include "SDL_stdinc.h"
32 #include "SDL_error.h"
34 #include "begin_code.h"
35 /* Set up for C function definitions, even when using C++ */
40 /** This is the read/write operation structure -- very basic */
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.
47 int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);
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.
53 int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
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.
59 int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);
61 /** Close and free an allocated SDL_FSops structure */
62 int (SDLCALL *close)(struct SDL_RWops *context);
66 #if defined(__WIN32__) && !defined(__SYMBIAN32__)
96 /** @name Functions to create SDL_RWops structures from various data sources */
99 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);
102 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
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);
108 extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
109 extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
113 /** @name Seek Reference Points */
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 */
120 /** @name Macros to easily read and write from an SDL_RWops structure */
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)
129 /** @name Read an item of the specified endianness and return in native format */
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);
139 /** @name Write an item of native format to the specified endianness */
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);
149 /* Ends C function definitions when using C++ */
153 #include "close_code.h"
155 #endif /* _SDL_rwops_h */