/*

     SDL - Simple DirectMedia Layer

     Copyright (C) 1997-2006 Sam Lantinga

     This library is free software; you can redistribute it and/or

     modify it under the terms of the GNU Lesser General Public

     License as published by the Free Software Foundation; either

     version 2.1 of the License, or (at your option) any later version.

     This library is distributed in the hope that it will be useful,

     but WITHOUT ANY WARRANTY; without even the implied warranty of

     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

     Lesser General Public License for more details.

     You should have received a copy of the GNU Lesser General Public

     License along with this library; if not, write to the Free Software

     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

     Sam Lantinga

     slouken@libsdl.org

 */

 /* This file provides a general interface for SDL to read and write

    data sources.  It can easily be extended to files, memory, etc.

 */

 #ifndef _SDL_RWops_h

 #define _SDL_RWops_h

 #include "SDL_config.h"

 #ifdef HAVE_STDIO_H

 #include <stdio.h>

 #endif

 #include "SDL_types.h"

 #include "begin_code.h"

 /* Set up for C function definitions, even when using C++ */

 #ifdef __cplusplus

 extern "C" {

 #endif

 /* This is the read/write operation structure -- very basic */

 typedef struct SDL_RWops {

 	/* Seek to 'offset' relative to whence, one of stdio's whence values:

 		SEEK_SET, SEEK_CUR, SEEK_END

 	   Returns the final offset in the data source.

 	 */

 	int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);

 	/* Read up to 'num' objects each of size 'objsize' from the data

 	   source to the area pointed at by 'ptr'.

 	   Returns the number of objects read, or -1 if the read failed.

 	 */

 	int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);

 	/* Write exactly 'num' objects each of size 'objsize' from the area

 	   pointed at by 'ptr' to data source.

 	   Returns 'num', or -1 if the write failed.

 	 */

 	int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);

 	/* Close and free an allocated SDL_FSops structure */

 	int (SDLCALL *close)(struct SDL_RWops *context);

 	Uint32 type;

 	union {

 #ifdef HAVE_STDIO_H

 	    struct {

 		int autoclose;

 	 	FILE *fp;

 	    } stdio;

 #endif

 	    struct {

 		Uint8 *base;

 	 	Uint8 *here;

 		Uint8 *stop;

 	    } mem;

 	    struct {

 		void *data1;

 	    } unknown;

 	} hidden;

 } SDL_RWops;

 /* Functions to create SDL_RWops structures from various data sources */

 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);

 #ifdef HAVE_STDIO_H

 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);

 #endif

 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);

 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromConstMem(const void *mem, int size);

 extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);

 extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);

 #define RW_SEEK_SET	0	/* Seek from the beginning of data */

 #define RW_SEEK_CUR	1	/* Seek relative to current read point */

 #define RW_SEEK_END	2	/* Seek relative to the end of data */

 /* Macros to easily read and write from an SDL_RWops structure */

 #define SDL_RWseek(ctx, offset, whence)	(ctx)->seek(ctx, offset, whence)

 #define SDL_RWtell(ctx)			(ctx)->seek(ctx, 0, RW_SEEK_CUR)

 #define SDL_RWread(ctx, ptr, size, n)	(ctx)->read(ctx, ptr, size, n)

 #define SDL_RWwrite(ctx, ptr, size, n)	(ctx)->write(ctx, ptr, size, n)

 #define SDL_RWclose(ctx)		(ctx)->close(ctx)

 /* Ends C function definitions when using C++ */

 #ifdef __cplusplus

 }

 #endif

 #include "close_code.h"

 #endif /* _SDL_RWops_h */