include/SDL_rwops.h
author Sam Lantinga <slouken@libsdl.org>
Wed, 06 Mar 2002 11:23:08 +0000
changeset 297 f6ffac90895c
parent 251 b8688cfdc232
child 337 9154ec9ca3d2
permissions -rw-r--r--
Updated copyright information for 2002
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Library General Public
     7     License as published by the Free Software Foundation; either
     8     version 2 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     Library General Public License for more details.
    14 
    15     You should have received a copy of the GNU Library General Public
    16     License along with this library; if not, write to the Free
    17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 #ifdef SAVE_RCSID
    24 static char rcsid =
    25  "@(#) $Id$";
    26 #endif
    27 
    28 /* This file provides a general interface for SDL to read and write
    29    data sources.  It can easily be extended to files, memory, etc.
    30 */
    31 
    32 #ifndef _SDL_RWops_h
    33 #define _SDL_RWops_h
    34 
    35 #include <stdio.h>
    36 
    37 #include "SDL_types.h"
    38 
    39 #include "begin_code.h"
    40 /* Set up for C function definitions, even when using C++ */
    41 #ifdef __cplusplus
    42 extern "C" {
    43 #endif
    44 
    45 /* This is the read/write operation structure -- very basic */
    46 
    47 typedef struct SDL_RWops {
    48 	/* Seek to 'offset' relative to whence, one of stdio's whence values:
    49 		SEEK_SET, SEEK_CUR, SEEK_END
    50 	   Returns the final offset in the data source.
    51 	 */
    52 	int (*seek)(struct SDL_RWops *context, int offset, int whence);
    53 
    54 	/* Read up to 'num' objects each of size 'objsize' from the data
    55 	   source to the area pointed at by 'ptr'.
    56 	   Returns the number of objects read, or -1 if the read failed.
    57 	 */
    58 	int (*read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
    59 
    60 	/* Write exactly 'num' objects each of size 'objsize' from the area
    61 	   pointed at by 'ptr' to data source.
    62 	   Returns 'num', or -1 if the write failed.
    63 	 */
    64 	int (*write)(struct SDL_RWops *context, const void *ptr, int size, int num);
    65 
    66 	/* Close and free an allocated SDL_FSops structure */
    67 	int (*close)(struct SDL_RWops *context);
    68 
    69 	Uint32 type;
    70 	union {
    71 	    struct {
    72 		int autoclose;
    73 	 	FILE *fp;
    74 	    } stdio;
    75 	    struct {
    76 		Uint8 *base;
    77 	 	Uint8 *here;
    78 		Uint8 *stop;
    79 	    } mem;
    80 	    struct {
    81 		void *data1;
    82 	    } unknown;
    83 	} hidden;
    84 
    85 } SDL_RWops;
    86 
    87 
    88 /* Functions to create SDL_RWops structures from various data sources */
    89 
    90 extern DECLSPEC SDL_RWops * SDL_RWFromFile(const char *file, const char *mode);
    91 
    92 extern DECLSPEC SDL_RWops * SDL_RWFromFP(FILE *fp, int autoclose);
    93 
    94 extern DECLSPEC SDL_RWops * SDL_RWFromMem(void *mem, int size);
    95 
    96 extern DECLSPEC SDL_RWops * SDL_AllocRW(void);
    97 extern DECLSPEC void SDL_FreeRW(SDL_RWops *area);
    98 
    99 /* Macros to easily read and write from an SDL_RWops structure */
   100 #define SDL_RWseek(ctx, offset, whence)	(ctx)->seek(ctx, offset, whence)
   101 #define SDL_RWtell(ctx)			(ctx)->seek(ctx, 0, SEEK_CUR)
   102 #define SDL_RWread(ctx, ptr, size, n)	(ctx)->read(ctx, ptr, size, n)
   103 #define SDL_RWwrite(ctx, ptr, size, n)	(ctx)->write(ctx, ptr, size, n)
   104 #define SDL_RWclose(ctx)		(ctx)->close(ctx)
   105 
   106 
   107 /* Ends C function definitions when using C++ */
   108 #ifdef __cplusplus
   109 }
   110 #endif
   111 #include "close_code.h"
   112 
   113 #endif /* _SDL_RWops_h */