include/SDL_rwops.h
author Sam Lantinga <slouken@libsdl.org>
Thu, 11 Apr 2002 14:35:16 +0000
changeset 337 9154ec9ca3d2
parent 297 f6ffac90895c
child 764 974c0fb74bf8
permissions -rw-r--r--
Explicitly specify the SDL API calling convention (C by default)
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/*
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    SDL - Simple DirectMedia Layer
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    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  Sam Lantinga
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    This library is free software; you can redistribute it and/or
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    modify it under the terms of the GNU Library General Public
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    License as published by the Free Software Foundation; either
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    version 2 of the License, or (at your option) any later version.
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    This library is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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    Library General Public License for more details.
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    You should have received a copy of the GNU Library General Public
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    License along with this library; if not, write to the Free
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    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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    Sam Lantinga
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    slouken@libsdl.org
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*/
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#ifdef SAVE_RCSID
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static char rcsid =
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 "@(#) $Id$";
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#endif
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/* This file provides a general interface for SDL to read and write
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   data sources.  It can easily be extended to files, memory, etc.
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*/
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#ifndef _SDL_RWops_h
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#define _SDL_RWops_h
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#include <stdio.h>
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#include "SDL_types.h"
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#include "begin_code.h"
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/* Set up for C function definitions, even when using C++ */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* This is the read/write operation structure -- very basic */
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typedef struct SDL_RWops {
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	/* Seek to 'offset' relative to whence, one of stdio's whence values:
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		SEEK_SET, SEEK_CUR, SEEK_END
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	   Returns the final offset in the data source.
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	 */
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	int (*seek)(struct SDL_RWops *context, int offset, int whence);
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	/* Read up to 'num' objects each of size 'objsize' from the data
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	   source to the area pointed at by 'ptr'.
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	   Returns the number of objects read, or -1 if the read failed.
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	 */
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	int (*read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
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	/* Write exactly 'num' objects each of size 'objsize' from the area
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	   pointed at by 'ptr' to data source.
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	   Returns 'num', or -1 if the write failed.
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	 */
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	int (*write)(struct SDL_RWops *context, const void *ptr, int size, int num);
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	/* Close and free an allocated SDL_FSops structure */
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	int (*close)(struct SDL_RWops *context);
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	Uint32 type;
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	union {
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	    struct {
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		int autoclose;
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	 	FILE *fp;
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	    } stdio;
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	    struct {
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		Uint8 *base;
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	 	Uint8 *here;
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		Uint8 *stop;
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	    } mem;
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	    struct {
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		void *data1;
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	    } unknown;
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	} hidden;
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} SDL_RWops;
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/* Functions to create SDL_RWops structures from various data sources */
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extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);
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extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
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extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);
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extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
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extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
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/* Macros to easily read and write from an SDL_RWops structure */
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#define SDL_RWseek(ctx, offset, whence)	(ctx)->seek(ctx, offset, whence)
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#define SDL_RWtell(ctx)			(ctx)->seek(ctx, 0, SEEK_CUR)
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#define SDL_RWread(ctx, ptr, size, n)	(ctx)->read(ctx, ptr, size, n)
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#define SDL_RWwrite(ctx, ptr, size, n)	(ctx)->write(ctx, ptr, size, n)
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#define SDL_RWclose(ctx)		(ctx)->close(ctx)
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/* Ends C function definitions when using C++ */
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#ifdef __cplusplus
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}
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#endif
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#include "close_code.h"
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#endif /* _SDL_RWops_h */