1/*
2    SDL - Simple DirectMedia Layer
3    Copyright (C) 1997-2012 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/** @file SDL_rwops.h
24 *  This file provides a general interface for SDL to read and write
25 *  data sources.  It can easily be extended to files, memory, etc.
26 */
27
28#ifndef _SDL_rwops_h
29#define _SDL_rwops_h
30
31#include "SDL_stdinc.h"
32#include "SDL_error.h"
33
34#include "begin_code.h"
35/* Set up for C function definitions, even when using C++ */
36#ifdef __cplusplus
37extern "C" {
38#endif
39
40/** This is the read/write operation structure -- very basic */
41
42typedef struct SDL_RWops {
43	/** Seek to 'offset' relative to whence, one of stdio's whence values:
44	 *	SEEK_SET, SEEK_CUR, SEEK_END
45	 *  Returns the final offset in the data source.
46	 */
47	int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);
48
49	/** Read up to 'maxnum' objects each of size 'size' from the data
50	 *  source to the area pointed at by 'ptr'.
51	 *  Returns the number of objects read, or -1 if the read failed.
52	 */
53	int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);
54
55	/** Write exactly 'num' objects each of size 'objsize' from the area
56	 *  pointed at by 'ptr' to data source.
57	 *  Returns 'num', or -1 if the write failed.
58	 */
59	int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);
60
61	/** Close and free an allocated SDL_FSops structure */
62	int (SDLCALL *close)(struct SDL_RWops *context);
63
64	Uint32 type;
65	union {
66#if defined(__WIN32__) && !defined(__SYMBIAN32__)
67	    struct {
68		int   append;
69		void *h;
70		struct {
71		    void *data;
72		    int size;
73		    int left;
74		} buffer;
75	    } win32io;
76#endif
77#ifdef HAVE_STDIO_H
78	    struct {
79		int autoclose;
80	 	FILE *fp;
81	    } stdio;
82#endif
83	    struct {
84		Uint8 *base;
85	 	Uint8 *here;
86		Uint8 *stop;
87	    } mem;
88	    struct {
89		void *data1;
90	    } unknown;
91	} hidden;
92
93} SDL_RWops;
94
95
96/** @name Functions to create SDL_RWops structures from various data sources */
97/*@{*/
98
99extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char *mode);
100
101#ifdef HAVE_STDIO_H
102extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
103#endif
104
105extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);
106extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromConstMem(const void *mem, int size);
107
108extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
109extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
110
111/*@}*/
112
113/** @name Seek Reference Points */
114/*@{*/
115#define RW_SEEK_SET	0	/**< Seek from the beginning of data */
116#define RW_SEEK_CUR	1	/**< Seek relative to current read point */
117#define RW_SEEK_END	2	/**< Seek relative to the end of data */
118/*@}*/
119
120/** @name Macros to easily read and write from an SDL_RWops structure */
121/*@{*/
122#define SDL_RWseek(ctx, offset, whence)	(ctx)->seek(ctx, offset, whence)
123#define SDL_RWtell(ctx)			(ctx)->seek(ctx, 0, RW_SEEK_CUR)
124#define SDL_RWread(ctx, ptr, size, n)	(ctx)->read(ctx, ptr, size, n)
125#define SDL_RWwrite(ctx, ptr, size, n)	(ctx)->write(ctx, ptr, size, n)
126#define SDL_RWclose(ctx)		(ctx)->close(ctx)
127/*@}*/
128
129/** @name Read an item of the specified endianness and return in native format */
130/*@{*/
131extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops *src);
132extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops *src);
133extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops *src);
134extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops *src);
135extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops *src);
136extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops *src);
137/*@}*/
138
139/** @name Write an item of native format to the specified endianness */
140/*@{*/
141extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
142extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
143extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
144extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
145extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
146extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
147/*@}*/
148
149/* Ends C function definitions when using C++ */
150#ifdef __cplusplus
151}
152#endif
153#include "close_code.h"
154
155#endif /* _SDL_rwops_h */
156