2 * copyright (c) 2001 Fabrice Bellard
4 * This file is part of FFmpeg.
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.
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.
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
20 #ifndef AVFORMAT_AVIO_H
21 #define AVFORMAT_AVIO_H
25 * unbuffered I/O operations
27 * @warning This file has to be considered an internal but installed
28 * header, so it should not be directly included in your projects.
33 #include "libavutil/common.h"
39 * New fields can be added to the end with minor version bumps.
40 * Removal, reordering and changes to existing fields require a major
42 * sizeof(URLContext) must not be used outside libav*.
44 typedef struct URLContext {
45 #if LIBAVFORMAT_VERSION_MAJOR >= 53
46 const AVClass *av_class; ///< information for av_log(). Set by url_open().
48 struct URLProtocol *prot;
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 */
53 char *filename; /**< specified URL */
56 typedef struct URLPollEntry {
66 typedef int URLInterruptCB(void);
69 * Creates an URLContext for accessing to the resource indicated by
70 * url, and opens it using the URLProtocol up.
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
76 * @return 0 in case of success, a negative value corresponding to an
77 * AVERROR code in case of failure
79 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
80 const char *url, int flags);
83 * Creates an URLContext for accessing to the resource indicated by
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
90 * @return 0 in case of success, a negative value corresponding to an
91 * AVERROR code in case of failure
93 int url_open(URLContext **h, const char *url, int flags);
96 * Reads up to size bytes from the resource accessed by h, and stores
97 * the read bytes in buf.
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).
104 int url_read(URLContext *h, unsigned char *buf, int size);
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.
114 int url_read_complete(URLContext *h, unsigned char *buf, int size);
115 int url_write(URLContext *h, unsigned char *buf, int size);
118 * Changes the position that will be used by the next read/write
119 * operation on the resource accessed by h.
121 * @param pos specifies the new position to set
122 * @param whence specifies how pos should be interpreted, it must be
123 * one of SEEK_SET (seek from the beginning), SEEK_CUR (seek from the
124 * current position), SEEK_END (seek from the end), or AVSEEK_SIZE
125 * (return the filesize of the requested resource, pos is ignored).
126 * @return a negative value corresponding to an AVERROR code in case
127 * of failure, or the resulting file position, measured in bytes from
128 * the beginning of the file. You can use this feature together with
129 * SEEK_CUR to read the current file position.
131 int64_t url_seek(URLContext *h, int64_t pos, int whence);
134 * Closes the resource accessed by the URLContext h, and frees the
137 * @return a negative value if an error condition occurred, 0
140 int url_close(URLContext *h);
143 * Returns a non-zero value if the resource indicated by url
144 * exists, 0 otherwise.
146 int url_exist(const char *url);
148 int64_t url_filesize(URLContext *h);
151 * Return the file descriptor associated with this URL. For RTP, this
152 * will return only the RTP file descriptor, not the RTCP file descriptor.
153 * To get both, use rtp_get_file_handles().
155 * @return the file descriptor associated with this URL, or <0 on error.
157 int url_get_file_handle(URLContext *h);
160 * Return the maximum packet size associated to packetized file
161 * handle. If the file is not packetized (stream like HTTP or file on
162 * disk), then 0 is returned.
164 * @param h file handle
165 * @return maximum packet size in bytes
167 int url_get_max_packet_size(URLContext *h);
168 void url_get_filename(URLContext *h, char *buf, int buf_size);
171 * The callback is called in blocking functions to test regulary if
172 * asynchronous interruption is needed. AVERROR(EINTR) is returned
173 * in this case by the interrupted function. 'NULL' means no interrupt
176 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
178 /* not implemented */
179 int url_poll(URLPollEntry *poll_table, int n, int timeout);
182 * Pause and resume playing - only meaningful if using a network streaming
183 * protocol (e.g. MMS).
184 * @param pause 1 for pause, 0 for resume
186 int av_url_read_pause(URLContext *h, int pause);
189 * Seek to a given timestamp relative to some component stream.
190 * Only meaningful if using a network streaming protocol (e.g. MMS.).
191 * @param stream_index The stream index that the timestamp is relative to.
192 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
193 * units from the beginning of the presentation.
194 * If a stream_index >= 0 is used and the protocol does not support
195 * seeking based on component streams, the call will fail with ENOTSUP.
196 * @param timestamp timestamp in AVStream.time_base units
197 * or if there is no stream specified then in AV_TIME_BASE units.
198 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
199 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
200 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
201 * fail with ENOTSUP if used and not supported.
202 * @return >= 0 on success
203 * @see AVInputFormat::read_seek
205 int64_t av_url_read_seek(URLContext *h, int stream_index,
206 int64_t timestamp, int flags);
209 * Passing this as the "whence" parameter to a seek function causes it to
210 * return the filesize without seeking anywhere. Supporting this is optional.
211 * If it is not supported then the seek function will return <0.
213 #define AVSEEK_SIZE 0x10000
216 * Oring this flag as into the "whence" parameter to a seek function causes it to
217 * seek by any means (like reopening and linear reading) or other normally unreasonble
218 * means that can be extreemly slow.
219 * This may be ignored by the seek code.
221 #define AVSEEK_FORCE 0x20000
223 typedef struct URLProtocol {
225 int (*url_open)(URLContext *h, const char *url, int flags);
226 int (*url_read)(URLContext *h, unsigned char *buf, int size);
227 int (*url_write)(URLContext *h, unsigned char *buf, int size);
228 int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
229 int (*url_close)(URLContext *h);
230 struct URLProtocol *next;
231 int (*url_read_pause)(URLContext *h, int pause);
232 int64_t (*url_read_seek)(URLContext *h, int stream_index,
233 int64_t timestamp, int flags);
234 int (*url_get_file_handle)(URLContext *h);
237 #if LIBAVFORMAT_VERSION_MAJOR < 53
238 extern URLProtocol *first_protocol;
241 extern URLInterruptCB *url_interrupt_cb;
244 * If protocol is NULL, returns the first registered protocol,
245 * if protocol is non-NULL, returns the next registered protocol after protocol,
246 * or NULL if protocol is the last one.
248 URLProtocol *av_protocol_next(URLProtocol *p);
250 #if LIBAVFORMAT_VERSION_MAJOR < 53
252 * @deprecated Use av_register_protocol() instead.
254 attribute_deprecated int register_protocol(URLProtocol *protocol);
258 * Registers the URLProtocol protocol.
260 int av_register_protocol(URLProtocol *protocol);
263 * Bytestream IO Context.
264 * New fields can be added to the end with minor version bumps.
265 * Removal, reordering and changes to existing fields require a major
267 * sizeof(ByteIOContext) must not be used outside libav*.
270 unsigned char *buffer;
272 unsigned char *buf_ptr, *buf_end;
274 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
275 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
276 int64_t (*seek)(void *opaque, int64_t offset, int whence);
277 int64_t pos; /**< position in the file of the current buffer */
278 int must_flush; /**< true if the next seek should flush */
279 int eof_reached; /**< true if eof reached */
280 int write_flag; /**< true if open for writing */
283 unsigned long checksum;
284 unsigned char *checksum_ptr;
285 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
286 int error; ///< contains the error code or 0 if no error happened
287 int (*read_pause)(void *opaque, int pause);
288 int64_t (*read_seek)(void *opaque, int stream_index,
289 int64_t timestamp, int flags);
292 int init_put_byte(ByteIOContext *s,
293 unsigned char *buffer,
297 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
298 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
299 int64_t (*seek)(void *opaque, int64_t offset, int whence));
300 ByteIOContext *av_alloc_put_byte(
301 unsigned char *buffer,
305 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
306 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
307 int64_t (*seek)(void *opaque, int64_t offset, int whence));
309 void put_byte(ByteIOContext *s, int b);
310 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
311 void put_le64(ByteIOContext *s, uint64_t val);
312 void put_be64(ByteIOContext *s, uint64_t val);
313 void put_le32(ByteIOContext *s, unsigned int val);
314 void put_be32(ByteIOContext *s, unsigned int val);
315 void put_le24(ByteIOContext *s, unsigned int val);
316 void put_be24(ByteIOContext *s, unsigned int val);
317 void put_le16(ByteIOContext *s, unsigned int val);
318 void put_be16(ByteIOContext *s, unsigned int val);
319 void put_tag(ByteIOContext *s, const char *tag);
321 void put_strz(ByteIOContext *s, const char *buf);
324 * fseek() equivalent for ByteIOContext.
325 * @return new position or AVERROR.
327 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
330 * Skip given number of bytes forward.
331 * @param offset number of bytes
333 void url_fskip(ByteIOContext *s, int64_t offset);
336 * ftell() equivalent for ByteIOContext.
337 * @return position or AVERROR.
339 int64_t url_ftell(ByteIOContext *s);
343 * @return filesize or AVERROR
345 int64_t url_fsize(ByteIOContext *s);
348 * feof() equivalent for ByteIOContext.
349 * @return non zero if and only if end of file
351 int url_feof(ByteIOContext *s);
353 int url_ferror(ByteIOContext *s);
355 int av_url_read_fpause(ByteIOContext *h, int pause);
356 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
357 int64_t timestamp, int flags);
360 /** @note return URL_EOF (-1) if EOF */
361 int url_fgetc(ByteIOContext *s);
363 /** @warning currently size is limited */
365 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
367 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
370 /** @note unlike fgets, the EOL character is not returned and a whole
371 line is parsed. return NULL if first char read was EOF */
372 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
374 void put_flush_packet(ByteIOContext *s);
378 * Reads size bytes from ByteIOContext into buf.
379 * @return number of bytes read or AVERROR
381 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
384 * Reads size bytes from ByteIOContext into buf.
385 * This reads at most 1 packet. If that is not enough fewer bytes will be
387 * @return number of bytes read or AVERROR
389 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
391 /** @note return 0 if EOF, so you cannot use it if EOF handling is
393 int get_byte(ByteIOContext *s);
394 unsigned int get_le24(ByteIOContext *s);
395 unsigned int get_le32(ByteIOContext *s);
396 uint64_t get_le64(ByteIOContext *s);
397 unsigned int get_le16(ByteIOContext *s);
399 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
400 unsigned int get_be16(ByteIOContext *s);
401 unsigned int get_be24(ByteIOContext *s);
402 unsigned int get_be32(ByteIOContext *s);
403 uint64_t get_be64(ByteIOContext *s);
405 uint64_t ff_get_v(ByteIOContext *bc);
407 static inline int url_is_streamed(ByteIOContext *s)
409 return s->is_streamed;
413 * Creates and initializes a ByteIOContext for accessing the
414 * resource referenced by the URLContext h.
415 * @note When the URLContext h has been opened in read+write mode, the
416 * ByteIOContext can be used only for writing.
418 * @param s Used to return the pointer to the created ByteIOContext.
419 * In case of failure the pointed to value is set to NULL.
420 * @return 0 in case of success, a negative value corresponding to an
421 * AVERROR code in case of failure
423 int url_fdopen(ByteIOContext **s, URLContext *h);
425 /** @warning must be called before any I/O */
426 int url_setbufsize(ByteIOContext *s, int buf_size);
427 #if LIBAVFORMAT_VERSION_MAJOR < 53
428 /** Reset the buffer for reading or writing.
429 * @note Will drop any data currently in the buffer without transmitting it.
430 * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
431 * to set up the buffer for writing. */
432 int url_resetbuf(ByteIOContext *s, int flags);
436 * Rewinds the ByteIOContext using the specified buffer containing the first buf_size bytes of the file.
437 * Used after probing to avoid seeking.
438 * Joins buf and s->buffer, taking any overlap into consideration.
439 * @note s->buffer must overlap with buf or they can't be joined and the function fails
440 * @note This function is NOT part of the public API
442 * @param s The read-only ByteIOContext to rewind
443 * @param buf The probe buffer containing the first buf_size bytes of the file
444 * @param buf_size The size of buf
445 * @return 0 in case of success, a negative value corresponding to an
446 * AVERROR code in case of failure
448 int ff_rewind_with_probe_data(ByteIOContext *s, unsigned char *buf, int buf_size);
451 * Creates and initializes a ByteIOContext for accessing the
452 * resource indicated by url.
453 * @note When the resource indicated by url has been opened in
454 * read+write mode, the ByteIOContext can be used only for writing.
456 * @param s Used to return the pointer to the created ByteIOContext.
457 * In case of failure the pointed to value is set to NULL.
458 * @param flags flags which control how the resource indicated by url
460 * @return 0 in case of success, a negative value corresponding to an
461 * AVERROR code in case of failure
463 int url_fopen(ByteIOContext **s, const char *url, int flags);
465 int url_fclose(ByteIOContext *s);
466 URLContext *url_fileno(ByteIOContext *s);
469 * Return the maximum packet size associated to packetized buffered file
470 * handle. If the file is not packetized (stream like http or file on
471 * disk), then 0 is returned.
473 * @param s buffered file handle
474 * @return maximum packet size in bytes
476 int url_fget_max_packet_size(ByteIOContext *s);
478 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
480 /** return the written or read size */
481 int url_close_buf(ByteIOContext *s);
484 * Open a write only memory stream.
486 * @param s new IO context
487 * @return zero if no error.
489 int url_open_dyn_buf(ByteIOContext **s);
492 * Open a write only packetized memory stream with a maximum packet
493 * size of 'max_packet_size'. The stream is stored in a memory buffer
494 * with a big endian 4 byte header giving the packet size in bytes.
496 * @param s new IO context
497 * @param max_packet_size maximum packet size (must be > 0)
498 * @return zero if no error.
500 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
503 * Return the written size and a pointer to the buffer. The buffer
504 * must be freed with av_free().
505 * @param s IO context
506 * @param pbuffer pointer to a byte buffer
507 * @return the length of the byte buffer
509 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
511 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
513 unsigned long get_checksum(ByteIOContext *s);
514 void init_checksum(ByteIOContext *s,
515 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
516 unsigned long checksum);
519 int udp_set_remote_url(URLContext *h, const char *uri);
520 int udp_get_local_port(URLContext *h);
521 #if (LIBAVFORMAT_VERSION_MAJOR <= 52)
522 int udp_get_file_handle(URLContext *h);
525 #endif /* AVFORMAT_AVIO_H */