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#include "SDL_error.h"
32
33#include "begin_code.h"
34/* Set up for C function definitions, even when using C++ */
35#ifdef __cplusplus
36extern "C" {
37#endif
38
39/* This is the read/write operation structure -- very basic */
40
41typedef struct SDL_RWops {
42	/* Seek to 'offset' relative to whence, one of stdio's whence values:
43		SEEK_SET, SEEK_CUR, SEEK_END
44	   Returns the final offset in the data source.
45	 */
46	int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);
47
48	/* Read up to 'num' objects each of size 'objsize' from the data
49	   source to the area pointed at by 'ptr'.
50	   Returns the number of objects read, or -1 if the read failed.
51	 */
52	int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
53
54	/* Write exactly 'num' objects each of size 'objsize' from the area
55	   pointed at by 'ptr' to data source.
56	   Returns 'num', or -1 if the write failed.
57	 */
58	int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);
59
60	/* Close and free an allocated SDL_FSops structure */
61	int (SDLCALL *close)(struct SDL_RWops *context);
62
63	Uint32 type;
64	union {
65#if defined(__WIN32__) && !defined(__SYMBIAN32__)
66	    struct {
67		int   append;
68		void *h;
69		struct {
70		    void *data;
71		    int size;
72		    int left;
73		} buffer;
74	    } win32io;
75#endif
76#ifdef HAVE_STDIO_H
77	    struct {
78		int autoclose;
79	 	FILE *fp;
80	    } stdio;
81#endif
82	    struct {
83		Uint8 *base;
84	 	Uint8 *here;
85		Uint8 *stop;
86	    } mem;
87	    struct {
88		void *data1;
89	    } unknown;
90	} hidden;
91
92} SDL_RWops;
93
94
95/* Functions to create SDL_RWops structures from various data sources */
96
97extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);
98
99#ifdef HAVE_STDIO_H
100extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
101#endif
102
103extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);
104extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromConstMem(const void *mem, int size);
105
106extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
107extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
108
109#define RW_SEEK_SET	0	/* Seek from the beginning of data */
110#define RW_SEEK_CUR	1	/* Seek relative to current read point */
111#define RW_SEEK_END	2	/* Seek relative to the end of data */
112
113/* Macros to easily read and write from an SDL_RWops structure */
114#define SDL_RWseek(ctx, offset, whence)	(ctx)->seek(ctx, offset, whence)
115#define SDL_RWtell(ctx)			(ctx)->seek(ctx, 0, RW_SEEK_CUR)
116#define SDL_RWread(ctx, ptr, size, n)	(ctx)->read(ctx, ptr, size, n)
117#define SDL_RWwrite(ctx, ptr, size, n)	(ctx)->write(ctx, ptr, size, n)
118#define SDL_RWclose(ctx)		(ctx)->close(ctx)
119
120
121/* Read an item of the specified endianness and return in native format */
122extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops *src);
123extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops *src);
124extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops *src);
125extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops *src);
126extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops *src);
127extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops *src);
128
129/* Write an item of native format to the specified endianness */
130extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
131extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
132extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
133extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
134extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
135extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
136
137
138/* Ends C function definitions when using C++ */
139#ifdef __cplusplus
140}
141#endif
142#include "close_code.h"
143
144#endif /* _SDL_rwops_h */
145