/*

    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 <stdio.h>

#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 {

	    struct {

		int autoclose;

	 	FILE *fp;

	    } stdio;

	    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);

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

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);

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

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

#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 */