include/SDL_rwops.h
author Sam Lantinga <slouken@libsdl.org>
Fri, 10 Feb 2006 03:19:02 +0000
changeset 1356 67114343400d
parent 1354 22f39393668a
child 1358 c71e05b4dc2e
permissions -rw-r--r--
*** empty log message ***
     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_stdinc.h"
    31 
    32 #include "begin_code.h"
    33 /* Set up for C function definitions, even when using C++ */
    34 #ifdef __cplusplus
    35 extern "C" {
    36 #endif
    37 
    38 /* This is the read/write operation structure -- very basic */
    39 
    40 typedef struct SDL_RWops {
    41 	/* Seek to 'offset' relative to whence, one of stdio's whence values:
    42 		SEEK_SET, SEEK_CUR, SEEK_END
    43 	   Returns the final offset in the data source.
    44 	 */
    45 	int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);
    46 
    47 	/* Read up to 'num' objects each of size 'objsize' from the data
    48 	   source to the area pointed at by 'ptr'.
    49 	   Returns the number of objects read, or -1 if the read failed.
    50 	 */
    51 	int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
    52 
    53 	/* Write exactly 'num' objects each of size 'objsize' from the area
    54 	   pointed at by 'ptr' to data source.
    55 	   Returns 'num', or -1 if the write failed.
    56 	 */
    57 	int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);
    58 
    59 	/* Close and free an allocated SDL_FSops structure */
    60 	int (SDLCALL *close)(struct SDL_RWops *context);
    61 
    62 	Uint32 type;
    63 	union {
    64 #ifdef HAVE_STDIO_H
    65 	    struct {
    66 		int autoclose;
    67 	 	FILE *fp;
    68 	    } stdio;
    69 #endif
    70 	    struct {
    71 		Uint8 *base;
    72 	 	Uint8 *here;
    73 		Uint8 *stop;
    74 	    } mem;
    75 	    struct {
    76 		void *data1;
    77 	    } unknown;
    78 	} hidden;
    79 
    80 } SDL_RWops;
    81 
    82 
    83 /* Functions to create SDL_RWops structures from various data sources */
    84 
    85 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);
    86 
    87 #ifdef HAVE_STDIO_H
    88 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
    89 #endif
    90 
    91 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);
    92 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromConstMem(const void *mem, int size);
    93 
    94 extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
    95 extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
    96 
    97 #define RW_SEEK_SET	0	/* Seek from the beginning of data */
    98 #define RW_SEEK_CUR	1	/* Seek relative to current read point */
    99 #define RW_SEEK_END	2	/* Seek relative to the end of data */
   100 
   101 /* Macros to easily read and write from an SDL_RWops structure */
   102 #define SDL_RWseek(ctx, offset, whence)	(ctx)->seek(ctx, offset, whence)
   103 #define SDL_RWtell(ctx)			(ctx)->seek(ctx, 0, RW_SEEK_CUR)
   104 #define SDL_RWread(ctx, ptr, size, n)	(ctx)->read(ctx, ptr, size, n)
   105 #define SDL_RWwrite(ctx, ptr, size, n)	(ctx)->write(ctx, ptr, size, n)
   106 #define SDL_RWclose(ctx)		(ctx)->close(ctx)
   107 
   108 
   109 /* Read an item of the specified endianness and return in native format */
   110 extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops *src);
   111 extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops *src);
   112 extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops *src);
   113 extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops *src);
   114 extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops *src);
   115 extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops *src);
   116 
   117 /* Write an item of native format to the specified endianness */
   118 extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
   119 extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
   120 extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
   121 extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
   122 extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
   123 extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
   124 
   125 
   126 /* Ends C function definitions when using C++ */
   127 #ifdef __cplusplus
   128 }
   129 #endif
   130 #include "close_code.h"
   131 
   132 #endif /* _SDL_RWops_h */