include/SDL_rwops.h
author Sam Lantinga <slouken@libsdl.org>
Tue, 07 Feb 2006 18:36:54 +0000
changeset 1345 7f32b9bede06
parent 1330 450721ad5436
child 1354 22f39393668a
permissions -rw-r--r--
Fixes for Visual C++ 6.0
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2006 Sam Lantinga
     4 
     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.
     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     Lesser General Public License for more details.
    14 
    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
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 /* This file provides a general interface for SDL to read and write
    24    data sources.  It can easily be extended to files, memory, etc.
    25 */
    26 
    27 #ifndef _SDL_RWops_h
    28 #define _SDL_RWops_h
    29 
    30 #include "SDL_config.h"
    31 
    32 #ifdef HAVE_STDIO_H
    33 #include <stdio.h>
    34 #endif
    35 
    36 #include "SDL_types.h"
    37 
    38 #include "begin_code.h"
    39 /* Set up for C function definitions, even when using C++ */
    40 #ifdef __cplusplus
    41 extern "C" {
    42 #endif
    43 
    44 /* This is the read/write operation structure -- very basic */
    45 
    46 typedef struct SDL_RWops {
    47 	/* Seek to 'offset' relative to whence, one of stdio's whence values:
    48 		SEEK_SET, SEEK_CUR, SEEK_END
    49 	   Returns the final offset in the data source.
    50 	 */
    51 	int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);
    52 
    53 	/* Read up to 'num' objects each of size 'objsize' from the data
    54 	   source to the area pointed at by 'ptr'.
    55 	   Returns the number of objects read, or -1 if the read failed.
    56 	 */
    57 	int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
    58 
    59 	/* Write exactly 'num' objects each of size 'objsize' from the area
    60 	   pointed at by 'ptr' to data source.
    61 	   Returns 'num', or -1 if the write failed.
    62 	 */
    63 	int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);
    64 
    65 	/* Close and free an allocated SDL_FSops structure */
    66 	int (SDLCALL *close)(struct SDL_RWops *context);
    67 
    68 	Uint32 type;
    69 	union {
    70 #ifdef HAVE_STDIO_H
    71 	    struct {
    72 		int autoclose;
    73 	 	FILE *fp;
    74 	    } stdio;
    75 #endif
    76 	    struct {
    77 		Uint8 *base;
    78 	 	Uint8 *here;
    79 		Uint8 *stop;
    80 	    } mem;
    81 	    struct {
    82 		void *data1;
    83 	    } unknown;
    84 	} hidden;
    85 
    86 } SDL_RWops;
    87 
    88 
    89 /* Functions to create SDL_RWops structures from various data sources */
    90 
    91 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);
    92 
    93 #ifdef HAVE_STDIO_H
    94 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
    95 #endif
    96 
    97 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);
    98 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromConstMem(const void *mem, int size);
    99 
   100 extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
   101 extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
   102 
   103 #define RW_SEEK_SET	0	/* Seek from the beginning of data */
   104 #define RW_SEEK_CUR	1	/* Seek relative to current read point */
   105 #define RW_SEEK_END	2	/* Seek relative to the end of data */
   106 
   107 /* Macros to easily read and write from an SDL_RWops structure */
   108 #define SDL_RWseek(ctx, offset, whence)	(ctx)->seek(ctx, offset, whence)
   109 #define SDL_RWtell(ctx)			(ctx)->seek(ctx, 0, RW_SEEK_CUR)
   110 #define SDL_RWread(ctx, ptr, size, n)	(ctx)->read(ctx, ptr, size, n)
   111 #define SDL_RWwrite(ctx, ptr, size, n)	(ctx)->write(ctx, ptr, size, n)
   112 #define SDL_RWclose(ctx)		(ctx)->close(ctx)
   113 
   114 
   115 /* Ends C function definitions when using C++ */
   116 #ifdef __cplusplus
   117 }
   118 #endif
   119 #include "close_code.h"
   120 
   121 #endif /* _SDL_RWops_h */