Doxument url_fdopen().
[libav.git] / libavformat / avio.h
1 /*
2 * copyright (c) 2001 Fabrice Bellard
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20 #ifndef AVFORMAT_AVIO_H
21 #define AVFORMAT_AVIO_H
22
23 /**
24 * @file libavformat/avio.h
25 * unbuffered I/O operations
26 *
27 * @warning This file has to be considered an internal but installed
28 * header, so it should not be directly included in your projects.
29 */
30
31 #include <stdint.h>
32
33 #include "libavutil/common.h"
34
35 /* unbuffered I/O */
36
37 /**
38 * URL Context.
39 * New fields can be added to the end with minor version bumps.
40 * Removal, reordering and changes to existing fields require a major
41 * version bump.
42 * sizeof(URLContext) must not be used outside libav*.
43 */
44 typedef struct URLContext {
45 #if LIBAVFORMAT_VERSION_MAJOR >= 53
46 const AVClass *av_class; ///< information for av_log(). Set by url_open().
47 #endif
48 struct URLProtocol *prot;
49 int flags;
50 int is_streamed; /**< true if streamed (no seek possible), default = false */
51 int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
52 void *priv_data;
53 char *filename; /**< specified URL */
54 } URLContext;
55
56 typedef struct URLPollEntry {
57 URLContext *handle;
58 int events;
59 int revents;
60 } URLPollEntry;
61
62 #define URL_RDONLY 0
63 #define URL_WRONLY 1
64 #define URL_RDWR 2
65
66 typedef int URLInterruptCB(void);
67
68 /**
69 * Creates an URLContext for accessing to the resource indicated by
70 * url, and opens it using the URLProtocol up.
71 *
72 * @param puc pointer to the location where, in case of success, the
73 * function puts the pointer to the created URLContext
74 * @param flags flags which control how the resource indicated by url
75 * is to be opened
76 * @return 0 in case of success, a negative value corresponding to an
77 * AVERROR code in case of failure
78 */
79 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
80 const char *url, int flags);
81
82 /**
83 * Creates an URLContext for accessing to the resource indicated by
84 * url, and opens it.
85 *
86 * @param puc pointer to the location where, in case of success, the
87 * function puts the pointer to the created URLContext
88 * @param flags flags which control how the resource indicated by url
89 * is to be opened
90 * @return 0 in case of success, a negative value corresponding to an
91 * AVERROR code in case of failure
92 */
93 int url_open(URLContext **h, const char *url, int flags);
94
95 /**
96 * Reads up to size bytes from the resource accessed by h, and stores
97 * the read bytes in buf.
98 *
99 * @return The number of bytes actually read, or a negative value
100 * corresponding to an AVERROR code in case of error. A value of zero
101 * indicates that it is not possible to read more from the accessed
102 * resource (except if the value of the size argument is also zero).
103 */
104 int url_read(URLContext *h, unsigned char *buf, int size);
105
106 /**
107 * Read as many bytes as possible (up to size), calling the
108 * read function multiple times if necessary.
109 * Will also retry if the read function returns AVERROR(EAGAIN).
110 * This makes special short-read handling in applications
111 * unnecessary, if the return value is < size then it is
112 * certain there was either an error or the end of file was reached.
113 */
114 int url_read_complete(URLContext *h, unsigned char *buf, int size);
115 int url_write(URLContext *h, unsigned char *buf, int size);
116 int64_t url_seek(URLContext *h, int64_t pos, int whence);
117
118 /**
119 * Closes the resource accessed by the URLContext h, and frees the
120 * memory used by it.
121 *
122 * @return a negative value if an error condition occurred, 0
123 * otherwise
124 */
125 int url_close(URLContext *h);
126
127 int url_exist(const char *url);
128 int64_t url_filesize(URLContext *h);
129
130 /**
131 * Return the file descriptor associated with this URL. For RTP, this
132 * will return only the RTP file descriptor, not the RTCP file descriptor.
133 * To get both, use rtp_get_file_handles().
134 *
135 * @return the file descriptor associated with this URL, or <0 on error.
136 */
137 int url_get_file_handle(URLContext *h);
138
139 /**
140 * Return the maximum packet size associated to packetized file
141 * handle. If the file is not packetized (stream like HTTP or file on
142 * disk), then 0 is returned.
143 *
144 * @param h file handle
145 * @return maximum packet size in bytes
146 */
147 int url_get_max_packet_size(URLContext *h);
148 void url_get_filename(URLContext *h, char *buf, int buf_size);
149
150 /**
151 * The callback is called in blocking functions to test regulary if
152 * asynchronous interruption is needed. AVERROR(EINTR) is returned
153 * in this case by the interrupted function. 'NULL' means no interrupt
154 * callback is given.
155 */
156 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
157
158 /* not implemented */
159 int url_poll(URLPollEntry *poll_table, int n, int timeout);
160
161 /**
162 * Pause and resume playing - only meaningful if using a network streaming
163 * protocol (e.g. MMS).
164 * @param pause 1 for pause, 0 for resume
165 */
166 int av_url_read_pause(URLContext *h, int pause);
167
168 /**
169 * Seek to a given timestamp relative to some component stream.
170 * Only meaningful if using a network streaming protocol (e.g. MMS.).
171 * @param stream_index The stream index that the timestamp is relative to.
172 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
173 * units from the beginning of the presentation.
174 * If a stream_index >= 0 is used and the protocol does not support
175 * seeking based on component streams, the call will fail with ENOTSUP.
176 * @param timestamp timestamp in AVStream.time_base units
177 * or if there is no stream specified then in AV_TIME_BASE units.
178 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
179 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
180 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
181 * fail with ENOTSUP if used and not supported.
182 * @return >= 0 on success
183 * @see AVInputFormat::read_seek
184 */
185 int64_t av_url_read_seek(URLContext *h, int stream_index,
186 int64_t timestamp, int flags);
187
188 /**
189 * Passing this as the "whence" parameter to a seek function causes it to
190 * return the filesize without seeking anywhere. Supporting this is optional.
191 * If it is not supported then the seek function will return <0.
192 */
193 #define AVSEEK_SIZE 0x10000
194
195 typedef struct URLProtocol {
196 const char *name;
197 int (*url_open)(URLContext *h, const char *url, int flags);
198 int (*url_read)(URLContext *h, unsigned char *buf, int size);
199 int (*url_write)(URLContext *h, unsigned char *buf, int size);
200 int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
201 int (*url_close)(URLContext *h);
202 struct URLProtocol *next;
203 int (*url_read_pause)(URLContext *h, int pause);
204 int64_t (*url_read_seek)(URLContext *h, int stream_index,
205 int64_t timestamp, int flags);
206 int (*url_get_file_handle)(URLContext *h);
207 } URLProtocol;
208
209 #if LIBAVFORMAT_VERSION_MAJOR < 53
210 extern URLProtocol *first_protocol;
211 #endif
212
213 extern URLInterruptCB *url_interrupt_cb;
214
215 /**
216 * If protocol is NULL, returns the first registered protocol,
217 * if protocol is non-NULL, returns the next registered protocol after protocol,
218 * or NULL if protocol is the last one.
219 */
220 URLProtocol *av_protocol_next(URLProtocol *p);
221
222 #if LIBAVFORMAT_VERSION_MAJOR < 53
223 /**
224 * @deprecated Use av_register_protocol() instead.
225 */
226 attribute_deprecated int register_protocol(URLProtocol *protocol);
227 #endif
228
229 /**
230 * Registers the URLProtocol protocol.
231 */
232 int av_register_protocol(URLProtocol *protocol);
233
234 /**
235 * Bytestream IO Context.
236 * New fields can be added to the end with minor version bumps.
237 * Removal, reordering and changes to existing fields require a major
238 * version bump.
239 * sizeof(ByteIOContext) must not be used outside libav*.
240 */
241 typedef struct {
242 unsigned char *buffer;
243 int buffer_size;
244 unsigned char *buf_ptr, *buf_end;
245 void *opaque;
246 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
247 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
248 int64_t (*seek)(void *opaque, int64_t offset, int whence);
249 int64_t pos; /**< position in the file of the current buffer */
250 int must_flush; /**< true if the next seek should flush */
251 int eof_reached; /**< true if eof reached */
252 int write_flag; /**< true if open for writing */
253 int is_streamed;
254 int max_packet_size;
255 unsigned long checksum;
256 unsigned char *checksum_ptr;
257 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
258 int error; ///< contains the error code or 0 if no error happened
259 int (*read_pause)(void *opaque, int pause);
260 int64_t (*read_seek)(void *opaque, int stream_index,
261 int64_t timestamp, int flags);
262 } ByteIOContext;
263
264 int init_put_byte(ByteIOContext *s,
265 unsigned char *buffer,
266 int buffer_size,
267 int write_flag,
268 void *opaque,
269 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
270 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
271 int64_t (*seek)(void *opaque, int64_t offset, int whence));
272 ByteIOContext *av_alloc_put_byte(
273 unsigned char *buffer,
274 int buffer_size,
275 int write_flag,
276 void *opaque,
277 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
278 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
279 int64_t (*seek)(void *opaque, int64_t offset, int whence));
280
281 void put_byte(ByteIOContext *s, int b);
282 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
283 void put_le64(ByteIOContext *s, uint64_t val);
284 void put_be64(ByteIOContext *s, uint64_t val);
285 void put_le32(ByteIOContext *s, unsigned int val);
286 void put_be32(ByteIOContext *s, unsigned int val);
287 void put_le24(ByteIOContext *s, unsigned int val);
288 void put_be24(ByteIOContext *s, unsigned int val);
289 void put_le16(ByteIOContext *s, unsigned int val);
290 void put_be16(ByteIOContext *s, unsigned int val);
291 void put_tag(ByteIOContext *s, const char *tag);
292
293 void put_strz(ByteIOContext *s, const char *buf);
294
295 /**
296 * fseek() equivalent for ByteIOContext.
297 * @return new position or AVERROR.
298 */
299 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
300
301 /**
302 * Skip given number of bytes forward.
303 * @param offset number of bytes
304 */
305 void url_fskip(ByteIOContext *s, int64_t offset);
306
307 /**
308 * ftell() equivalent for ByteIOContext.
309 * @return position or AVERROR.
310 */
311 int64_t url_ftell(ByteIOContext *s);
312
313 /**
314 * Gets the filesize.
315 * @return filesize or AVERROR
316 */
317 int64_t url_fsize(ByteIOContext *s);
318
319 /**
320 * feof() equivalent for ByteIOContext.
321 * @return non zero if and only if end of file
322 */
323 int url_feof(ByteIOContext *s);
324
325 int url_ferror(ByteIOContext *s);
326
327 int av_url_read_fpause(ByteIOContext *h, int pause);
328 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
329 int64_t timestamp, int flags);
330
331 #define URL_EOF (-1)
332 /** @note return URL_EOF (-1) if EOF */
333 int url_fgetc(ByteIOContext *s);
334
335 /** @warning currently size is limited */
336 #ifdef __GNUC__
337 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
338 #else
339 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
340 #endif
341
342 /** @note unlike fgets, the EOL character is not returned and a whole
343 line is parsed. return NULL if first char read was EOF */
344 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
345
346 void put_flush_packet(ByteIOContext *s);
347
348
349 /**
350 * Reads size bytes from ByteIOContext into buf.
351 * @returns number of bytes read or AVERROR
352 */
353 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
354
355 /**
356 * Reads size bytes from ByteIOContext into buf.
357 * This reads at most 1 packet. If that is not enough fewer bytes will be
358 * returned.
359 * @returns number of bytes read or AVERROR
360 */
361 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
362
363 /** @note return 0 if EOF, so you cannot use it if EOF handling is
364 necessary */
365 int get_byte(ByteIOContext *s);
366 unsigned int get_le24(ByteIOContext *s);
367 unsigned int get_le32(ByteIOContext *s);
368 uint64_t get_le64(ByteIOContext *s);
369 unsigned int get_le16(ByteIOContext *s);
370
371 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
372 unsigned int get_be16(ByteIOContext *s);
373 unsigned int get_be24(ByteIOContext *s);
374 unsigned int get_be32(ByteIOContext *s);
375 uint64_t get_be64(ByteIOContext *s);
376
377 uint64_t ff_get_v(ByteIOContext *bc);
378
379 static inline int url_is_streamed(ByteIOContext *s)
380 {
381 return s->is_streamed;
382 }
383
384 /**
385 * Creates and initializes a ByteIOContext for accessing the
386 * resource referenced by the URLContext h.
387 * @note When the URLContext h has been opened in read+write mode, the
388 * ByteIOContext can be used only for writing.
389 *
390 * @param s Used to return the pointer to the created ByteIOContext.
391 * In case of failure the pointed to value is set to NULL.
392 * @return 0 in case of success, a negative value corresponding to an
393 * AVERROR code in case of failure
394 */
395 int url_fdopen(ByteIOContext **s, URLContext *h);
396
397 /** @warning must be called before any I/O */
398 int url_setbufsize(ByteIOContext *s, int buf_size);
399 #if LIBAVFORMAT_VERSION_MAJOR < 53
400 /** Reset the buffer for reading or writing.
401 * @note Will drop any data currently in the buffer without transmitting it.
402 * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
403 * to set up the buffer for writing. */
404 int url_resetbuf(ByteIOContext *s, int flags);
405 #endif
406
407 /** @note when opened as read/write, the buffers are only used for
408 writing */
409 int url_fopen(ByteIOContext **s, const char *url, int flags);
410 int url_fclose(ByteIOContext *s);
411 URLContext *url_fileno(ByteIOContext *s);
412
413 /**
414 * Return the maximum packet size associated to packetized buffered file
415 * handle. If the file is not packetized (stream like http or file on
416 * disk), then 0 is returned.
417 *
418 * @param s buffered file handle
419 * @return maximum packet size in bytes
420 */
421 int url_fget_max_packet_size(ByteIOContext *s);
422
423 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
424
425 /** return the written or read size */
426 int url_close_buf(ByteIOContext *s);
427
428 /**
429 * Open a write only memory stream.
430 *
431 * @param s new IO context
432 * @return zero if no error.
433 */
434 int url_open_dyn_buf(ByteIOContext **s);
435
436 /**
437 * Open a write only packetized memory stream with a maximum packet
438 * size of 'max_packet_size'. The stream is stored in a memory buffer
439 * with a big endian 4 byte header giving the packet size in bytes.
440 *
441 * @param s new IO context
442 * @param max_packet_size maximum packet size (must be > 0)
443 * @return zero if no error.
444 */
445 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
446
447 /**
448 * Return the written size and a pointer to the buffer. The buffer
449 * must be freed with av_free().
450 * @param s IO context
451 * @param pbuffer pointer to a byte buffer
452 * @return the length of the byte buffer
453 */
454 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
455
456 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
457 unsigned int len);
458 unsigned long get_checksum(ByteIOContext *s);
459 void init_checksum(ByteIOContext *s,
460 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
461 unsigned long checksum);
462
463 /* udp.c */
464 int udp_set_remote_url(URLContext *h, const char *uri);
465 int udp_get_local_port(URLContext *h);
466 #if (LIBAVFORMAT_VERSION_MAJOR <= 52)
467 int udp_get_file_handle(URLContext *h);
468 #endif
469
470 #endif /* AVFORMAT_AVIO_H */