1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20*/
21
22/**
23 * \file SDL_rwops.h
24 *
25 * This file provides a general interface for SDL to read and write
26 * data streams. It can easily be extended to files, memory, etc.
27 */
28
29#ifndef SDL_rwops_h_
30#define SDL_rwops_h_
31
32#include "SDL_stdinc.h"
33#include "SDL_error.h"
34
35#include "begin_code.h"
36/* Set up for C function definitions, even when using C++ */
37#ifdef __cplusplus
38extern "C" {
39#endif
40
41/* RWops Types */
42#define SDL_RWOPS_UNKNOWN 0U /**< Unknown stream type */
43#define SDL_RWOPS_WINFILE 1U /**< Win32 file */
44#define SDL_RWOPS_STDFILE 2U /**< Stdio file */
45#define SDL_RWOPS_JNIFILE 3U /**< Android asset */
46#define SDL_RWOPS_MEMORY 4U /**< Memory stream */
47#define SDL_RWOPS_MEMORY_RO 5U /**< Read-Only memory stream */
48#if defined(__VITA__)
49#define SDL_RWOPS_VITAFILE 6U /**< Vita file */
50#endif
51
52/**
53 * This is the read/write operation structure -- very basic.
54 */
55typedef struct SDL_RWops
56{
57 /**
58 * Return the size of the file in this rwops, or -1 if unknown
59 */
60 Sint64 (SDLCALL * size) (struct SDL_RWops * context);
61
62 /**
63 * Seek to \c offset relative to \c whence, one of stdio's whence values:
64 * RW_SEEK_SET, RW_SEEK_CUR, RW_SEEK_END
65 *
66 * \return the final offset in the data stream, or -1 on error.
67 */
68 Sint64 (SDLCALL * seek) (struct SDL_RWops * context, Sint64 offset,
69 int whence);
70
71 /**
72 * Read up to \c maxnum objects each of size \c size from the data
73 * stream to the area pointed at by \c ptr.
74 *
75 * \return the number of objects read, or 0 at error or end of file.
76 */
77 size_t (SDLCALL * read) (struct SDL_RWops * context, void *ptr,
78 size_t size, size_t maxnum);
79
80 /**
81 * Write exactly \c num objects each of size \c size from the area
82 * pointed at by \c ptr to data stream.
83 *
84 * \return the number of objects written, or 0 at error or end of file.
85 */
86 size_t (SDLCALL * write) (struct SDL_RWops * context, const void *ptr,
87 size_t size, size_t num);
88
89 /**
90 * Close and free an allocated SDL_RWops structure.
91 *
92 * \return 0 if successful or -1 on write error when flushing data.
93 */
94 int (SDLCALL * close) (struct SDL_RWops * context);
95
96 Uint32 type;
97 union
98 {
99#if defined(__ANDROID__)
100 struct
101 {
102 void *asset;
103 } androidio;
104#elif defined(__WIN32__)
105 struct
106 {
107 SDL_bool append;
108 void *h;
109 struct
110 {
111 void *data;
112 size_t size;
113 size_t left;
114 } buffer;
115 } windowsio;
116#elif defined(__VITA__)
117 struct
118 {
119 int h;
120 struct
121 {
122 void *data;
123 size_t size;
124 size_t left;
125 } buffer;
126 } vitaio;
127#endif
128
129#ifdef HAVE_STDIO_H
130 struct
131 {
132 SDL_bool autoclose;
133 FILE *fp;
134 } stdio;
135#endif
136 struct
137 {
138 Uint8 *base;
139 Uint8 *here;
140 Uint8 *stop;
141 } mem;
142 struct
143 {
144 void *data1;
145 void *data2;
146 } unknown;
147 } hidden;
148
149} SDL_RWops;
150
151
152/**
153 * \name RWFrom functions
154 *
155 * Functions to create SDL_RWops structures from various data streams.
156 */
157/* @{ */
158
159extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFile(const char *file,
160 const char *mode);
161
162#ifdef HAVE_STDIO_H
163extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFP(FILE * fp,
164 SDL_bool autoclose);
165#else
166extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromFP(void * fp,
167 SDL_bool autoclose);
168#endif
169
170extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromMem(void *mem, int size);
171extern DECLSPEC SDL_RWops *SDLCALL SDL_RWFromConstMem(const void *mem,
172 int size);
173
174/* @} *//* RWFrom functions */
175
176
177extern DECLSPEC SDL_RWops *SDLCALL SDL_AllocRW(void);
178extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops * area);
179
180#define RW_SEEK_SET 0 /**< Seek from the beginning of data */
181#define RW_SEEK_CUR 1 /**< Seek relative to current read point */
182#define RW_SEEK_END 2 /**< Seek relative to the end of data */
183
184/**
185 * Use this macro to get the size of the data stream in an SDL_RWops.
186 *
187 * \param context the SDL_RWops to get the size of the data stream from
188 * \returns the size of the data stream in the SDL_RWops on success, -1 if
189 * unknown or a negative error code on failure; call SDL_GetError()
190 * for more information.
191 *
192 * \since This function is available since SDL 2.0.0.
193 */
194extern DECLSPEC Sint64 SDLCALL SDL_RWsize(SDL_RWops *context);
195
196/**
197 * Seek within an SDL_RWops data stream.
198 *
199 * This function seeks to byte `offset`, relative to `whence`.
200 *
201 * `whence` may be any of the following values:
202 *
203 * - `RW_SEEK_SET`: seek from the beginning of data
204 * - `RW_SEEK_CUR`: seek relative to current read point
205 * - `RW_SEEK_END`: seek relative to the end of data
206 *
207 * If this stream can not seek, it will return -1.
208 *
209 * SDL_RWseek() is actually a wrapper function that calls the SDL_RWops's
210 * `seek` method appropriately, to simplify application development.
211 *
212 * \param context a pointer to an SDL_RWops structure
213 * \param offset an offset in bytes, relative to **whence** location; can be
214 * negative
215 * \param whence any of `RW_SEEK_SET`, `RW_SEEK_CUR`, `RW_SEEK_END`
216 * \returns the final offset in the data stream after the seek or -1 on error.
217 *
218 * \sa SDL_RWclose
219 * \sa SDL_RWFromConstMem
220 * \sa SDL_RWFromFile
221 * \sa SDL_RWFromFP
222 * \sa SDL_RWFromMem
223 * \sa SDL_RWread
224 * \sa SDL_RWtell
225 * \sa SDL_RWwrite
226 */
227extern DECLSPEC Sint64 SDLCALL SDL_RWseek(SDL_RWops *context,
228 Sint64 offset, int whence);
229
230/**
231 * Determine the current read/write offset in an SDL_RWops data stream.
232 *
233 * SDL_RWtell is actually a wrapper function that calls the SDL_RWops's
234 * `seek` method, with an offset of 0 bytes from `RW_SEEK_CUR`, to simplify
235 * application development.
236 *
237 * \param context a SDL_RWops data stream object from which to get the current
238 * offset
239 * \returns the current offset in the stream, or -1 if the information can not
240 * be determined.
241 *
242 * \sa SDL_RWclose
243 * \sa SDL_RWFromConstMem
244 * \sa SDL_RWFromFile
245 * \sa SDL_RWFromFP
246 * \sa SDL_RWFromMem
247 * \sa SDL_RWread
248 * \sa SDL_RWseek
249 * \sa SDL_RWwrite
250 */
251extern DECLSPEC Sint64 SDLCALL SDL_RWtell(SDL_RWops *context);
252
253/**
254 * Read from a data source.
255 *
256 * This function reads up to `maxnum` objects each of size `size` from the
257 * data source to the area pointed at by `ptr`. This function may read less
258 * objects than requested. It will return zero when there has been an error or
259 * the data stream is completely read.
260 *
261 * SDL_RWread() is actually a function wrapper that calls the SDL_RWops's
262 * `read` method appropriately, to simplify application development.
263 *
264 * \param context a pointer to an SDL_RWops structure
265 * \param ptr a pointer to a buffer to read data into
266 * \param size the size of each object to read, in bytes
267 * \param maxnum the maximum number of objects to be read
268 * \returns the number of objects read, or 0 at error or end of file; call
269 * SDL_GetError() for more information.
270 *
271 * \sa SDL_RWclose
272 * \sa SDL_RWFromConstMem
273 * \sa SDL_RWFromFile
274 * \sa SDL_RWFromFP
275 * \sa SDL_RWFromMem
276 * \sa SDL_RWseek
277 * \sa SDL_RWwrite
278 */
279extern DECLSPEC size_t SDLCALL SDL_RWread(SDL_RWops *context,
280 void *ptr, size_t size,
281 size_t maxnum);
282
283/**
284 * Write to an SDL_RWops data stream.
285 *
286 * This function writes exactly `num` objects each of size `size` from the
287 * area pointed at by `ptr` to the stream. If this fails for any reason,
288 * it'll return less than `num` to demonstrate how far the write progressed.
289 * On success, it returns `num`.
290 *
291 * SDL_RWwrite is actually a function wrapper that calls the SDL_RWops's
292 * `write` method appropriately, to simplify application development.
293 *
294 * \param context a pointer to an SDL_RWops structure
295 * \param ptr a pointer to a buffer containing data to write
296 * \param size the size of an object to write, in bytes
297 * \param num the number of objects to write
298 * \returns the number of objects written, which will be less than **num** on
299 * error; call SDL_GetError() for more information.
300 *
301 * \sa SDL_RWclose
302 * \sa SDL_RWFromConstMem
303 * \sa SDL_RWFromFile
304 * \sa SDL_RWFromFP
305 * \sa SDL_RWFromMem
306 * \sa SDL_RWread
307 * \sa SDL_RWseek
308 */
309extern DECLSPEC size_t SDLCALL SDL_RWwrite(SDL_RWops *context,
310 const void *ptr, size_t size,
311 size_t num);
312
313/**
314 * Close and free an allocated SDL_RWops structure.
315 *
316 * SDL_RWclose() closes and cleans up the SDL_RWops stream. It releases any
317 * resources used by the stream and frees the SDL_RWops itself with
318 * SDL_FreeRW(). This returns 0 on success, or -1 if the stream failed to
319 * flush to its output (e.g. to disk).
320 *
321 * Note that if this fails to flush the stream to disk, this function reports
322 * an error, but the SDL_RWops is still invalid once this function returns.
323 *
324 * SDL_RWclose() is actually a macro that calls the SDL_RWops's `close`
325 * method appropriately, to simplify application development.
326 *
327 * \param context SDL_RWops structure to close
328 * \returns 0 on success or a negative error code on failure; call
329 * SDL_GetError() for more information.
330 *
331 * \sa SDL_RWFromConstMem
332 * \sa SDL_RWFromFile
333 * \sa SDL_RWFromFP
334 * \sa SDL_RWFromMem
335 * \sa SDL_RWread
336 * \sa SDL_RWseek
337 * \sa SDL_RWwrite
338 */
339extern DECLSPEC int SDLCALL SDL_RWclose(SDL_RWops *context);
340
341/**
342 * Load all the data from an SDL data stream.
343 *
344 * The data is allocated with a zero byte at the end (null terminated) for
345 * convenience. This extra byte is not included in the value reported via
346 * `datasize`.
347 *
348 * The data should be freed with SDL_free().
349 *
350 * \param src the SDL_RWops to read all available data from
351 * \param datasize if not NULL, will store the number of bytes read
352 * \param freesrc if non-zero, calls SDL_RWclose() on `src` before returning
353 * \returns the data, or NULL if there was an error.
354 */
355extern DECLSPEC void *SDLCALL SDL_LoadFile_RW(SDL_RWops *src,
356 size_t *datasize,
357 int freesrc);
358
359/**
360 * Load all the data from a file path.
361 *
362 * The data is allocated with a zero byte at the end (null terminated) for
363 * convenience. This extra byte is not included in the value reported via
364 * `datasize`.
365 *
366 * The data should be freed with SDL_free().
367 *
368 * \param file the path to read all available data from
369 * \param datasize if not NULL, will store the number of bytes read
370 * \returns the data, or NULL if there was an error.
371 */
372extern DECLSPEC void *SDLCALL SDL_LoadFile(const char *file, size_t *datasize);
373
374/**
375 * \name Read endian functions
376 *
377 * Read an item of the specified endianness and return in native format.
378 */
379/* @{ */
380extern DECLSPEC Uint8 SDLCALL SDL_ReadU8(SDL_RWops * src);
381extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops * src);
382extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops * src);
383extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops * src);
384extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops * src);
385extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops * src);
386extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops * src);
387/* @} *//* Read endian functions */
388
389/**
390 * \name Write endian functions
391 *
392 * Write an item of native format to the specified endianness.
393 */
394/* @{ */
395extern DECLSPEC size_t SDLCALL SDL_WriteU8(SDL_RWops * dst, Uint8 value);
396extern DECLSPEC size_t SDLCALL SDL_WriteLE16(SDL_RWops * dst, Uint16 value);
397extern DECLSPEC size_t SDLCALL SDL_WriteBE16(SDL_RWops * dst, Uint16 value);
398extern DECLSPEC size_t SDLCALL SDL_WriteLE32(SDL_RWops * dst, Uint32 value);
399extern DECLSPEC size_t SDLCALL SDL_WriteBE32(SDL_RWops * dst, Uint32 value);
400extern DECLSPEC size_t SDLCALL SDL_WriteLE64(SDL_RWops * dst, Uint64 value);
401extern DECLSPEC size_t SDLCALL SDL_WriteBE64(SDL_RWops * dst, Uint64 value);
402/* @} *//* Write endian functions */
403
404/* Ends C function definitions when using C++ */
405#ifdef __cplusplus
406}
407#endif
408#include "close_code.h"
409
410#endif /* SDL_rwops_h_ */
411
412/* vi: set ts=4 sw=4 expandtab: */
413