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"
34 #include "libavutil/log.h"
40 * New fields can be added to the end with minor version bumps.
41 * Removal, reordering and changes to existing fields require a major
43 * sizeof(URLContext) must not be used outside libav*.
45 typedef struct URLContext {
47 const AVClass *av_class; ///< information for av_log(). Set by url_open().
49 struct URLProtocol *prot;
51 int is_streamed; /**< true if streamed (no seek possible), default = false */
52 int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
54 char *filename; /**< specified URL */
58 typedef struct URLPollEntry {
68 typedef int URLInterruptCB(void);
71 * Create a URLContext for accessing to the resource indicated by
72 * url, and open it using the URLProtocol up.
74 * @param puc pointer to the location where, in case of success, the
75 * function puts the pointer to the created URLContext
76 * @param flags flags which control how the resource indicated by url
78 * @return 0 in case of success, a negative value corresponding to an
79 * AVERROR code in case of failure
81 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
82 const char *url, int flags);
85 * Create a URLContext for accessing to the resource indicated by
86 * url, but do not initiate the connection yet.
88 * @param puc pointer to the location where, in case of success, the
89 * function puts the pointer to the created URLContext
90 * @param flags flags which control how the resource indicated by url
92 * @return 0 in case of success, a negative value corresponding to an
93 * AVERROR code in case of failure
95 int url_alloc(URLContext **h, const char *url, int flags);
98 * Connect an URLContext that has been allocated by url_alloc
100 int url_connect(URLContext *h);
103 * Create an URLContext for accessing to the resource indicated by
106 * @param puc pointer to the location where, in case of success, the
107 * function puts the pointer to the created URLContext
108 * @param flags flags which control how the resource indicated by url
110 * @return 0 in case of success, a negative value corresponding to an
111 * AVERROR code in case of failure
113 int url_open(URLContext **h, const char *url, int flags);
116 * Read up to size bytes from the resource accessed by h, and store
117 * the read bytes in buf.
119 * @return The number of bytes actually read, or a negative value
120 * corresponding to an AVERROR code in case of error. A value of zero
121 * indicates that it is not possible to read more from the accessed
122 * resource (except if the value of the size argument is also zero).
124 int url_read(URLContext *h, unsigned char *buf, int size);
127 * Read as many bytes as possible (up to size), calling the
128 * read function multiple times if necessary.
129 * Will also retry if the read function returns AVERROR(EAGAIN).
130 * This makes special short-read handling in applications
131 * unnecessary, if the return value is < size then it is
132 * certain there was either an error or the end of file was reached.
134 int url_read_complete(URLContext *h, unsigned char *buf, int size);
135 int url_write(URLContext *h, const unsigned char *buf, int size);
138 * Passing this as the "whence" parameter to a seek function causes it to
139 * return the filesize without seeking anywhere. Supporting this is optional.
140 * If it is not supported then the seek function will return <0.
142 #define AVSEEK_SIZE 0x10000
145 * Change the position that will be used by the next read/write
146 * operation on the resource accessed by h.
148 * @param pos specifies the new position to set
149 * @param whence specifies how pos should be interpreted, it must be
150 * one of SEEK_SET (seek from the beginning), SEEK_CUR (seek from the
151 * current position), SEEK_END (seek from the end), or AVSEEK_SIZE
152 * (return the filesize of the requested resource, pos is ignored).
153 * @return a negative value corresponding to an AVERROR code in case
154 * of failure, or the resulting file position, measured in bytes from
155 * the beginning of the file. You can use this feature together with
156 * SEEK_CUR to read the current file position.
158 int64_t url_seek(URLContext *h, int64_t pos, int whence);
161 * Close the resource accessed by the URLContext h, and free the
164 * @return a negative value if an error condition occurred, 0
167 int url_close(URLContext *h);
170 * Return a non-zero value if the resource indicated by url
171 * exists, 0 otherwise.
173 int url_exist(const char *url);
176 * Return the filesize of the resource accessed by h, AVERROR(ENOSYS)
177 * if the operation is not supported by h, or another negative value
178 * corresponding to an AVERROR error code in case of failure.
180 int64_t url_filesize(URLContext *h);
183 * Return the file descriptor associated with this URL. For RTP, this
184 * will return only the RTP file descriptor, not the RTCP file descriptor.
185 * To get both, use rtp_get_file_handles().
187 * @return the file descriptor associated with this URL, or <0 on error.
189 int url_get_file_handle(URLContext *h);
192 * Return the maximum packet size associated to packetized file
193 * handle. If the file is not packetized (stream like HTTP or file on
194 * disk), then 0 is returned.
196 * @param h file handle
197 * @return maximum packet size in bytes
199 int url_get_max_packet_size(URLContext *h);
202 * Copy the filename of the resource accessed by h to buf.
204 * @param buf_size size in bytes of buf
206 void url_get_filename(URLContext *h, char *buf, int buf_size);
209 * The callback is called in blocking functions to test regulary if
210 * asynchronous interruption is needed. AVERROR(EINTR) is returned
211 * in this case by the interrupted function. 'NULL' means no interrupt
214 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
216 /* not implemented */
217 int url_poll(URLPollEntry *poll_table, int n, int timeout);
220 * Pause and resume playing - only meaningful if using a network streaming
221 * protocol (e.g. MMS).
222 * @param pause 1 for pause, 0 for resume
224 int av_url_read_pause(URLContext *h, int pause);
227 * Seek to a given timestamp relative to some component stream.
228 * Only meaningful if using a network streaming protocol (e.g. MMS.).
229 * @param stream_index The stream index that the timestamp is relative to.
230 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
231 * units from the beginning of the presentation.
232 * If a stream_index >= 0 is used and the protocol does not support
233 * seeking based on component streams, the call will fail with ENOTSUP.
234 * @param timestamp timestamp in AVStream.time_base units
235 * or if there is no stream specified then in AV_TIME_BASE units.
236 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
237 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
238 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
239 * fail with ENOTSUP if used and not supported.
240 * @return >= 0 on success
241 * @see AVInputFormat::read_seek
243 int64_t av_url_read_seek(URLContext *h, int stream_index,
244 int64_t timestamp, int flags);
247 * Oring this flag as into the "whence" parameter to a seek function causes it to
248 * seek by any means (like reopening and linear reading) or other normally unreasonble
249 * means that can be extreemly slow.
250 * This may be ignored by the seek code.
252 #define AVSEEK_FORCE 0x20000
254 typedef struct URLProtocol {
256 int (*url_open)(URLContext *h, const char *url, int flags);
257 int (*url_read)(URLContext *h, unsigned char *buf, int size);
258 int (*url_write)(URLContext *h, const unsigned char *buf, int size);
259 int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
260 int (*url_close)(URLContext *h);
261 struct URLProtocol *next;
262 int (*url_read_pause)(URLContext *h, int pause);
263 int64_t (*url_read_seek)(URLContext *h, int stream_index,
264 int64_t timestamp, int flags);
265 int (*url_get_file_handle)(URLContext *h);
267 const AVClass *priv_data_class;
270 #if FF_API_REGISTER_PROTOCOL
271 extern URLProtocol *first_protocol;
274 extern URLInterruptCB *url_interrupt_cb;
277 * If protocol is NULL, returns the first registered protocol,
278 * if protocol is non-NULL, returns the next registered protocol after protocol,
279 * or NULL if protocol is the last one.
281 URLProtocol *av_protocol_next(URLProtocol *p);
283 #if FF_API_REGISTER_PROTOCOL
285 * @deprecated Use av_register_protocol() instead.
287 attribute_deprecated int register_protocol(URLProtocol *protocol);
290 * @deprecated Use av_register_protocol2() instead.
292 attribute_deprecated int av_register_protocol(URLProtocol *protocol);
296 * Register the URLProtocol protocol.
298 * @param size the size of the URLProtocol struct referenced
300 int av_register_protocol2(URLProtocol *protocol, int size);
303 * Bytestream IO Context.
304 * New fields can be added to the end with minor version bumps.
305 * Removal, reordering and changes to existing fields require a major
307 * sizeof(ByteIOContext) must not be used outside libav*.
310 unsigned char *buffer;
312 unsigned char *buf_ptr, *buf_end;
314 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
315 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
316 int64_t (*seek)(void *opaque, int64_t offset, int whence);
317 int64_t pos; /**< position in the file of the current buffer */
318 int must_flush; /**< true if the next seek should flush */
319 int eof_reached; /**< true if eof reached */
320 int write_flag; /**< true if open for writing */
323 unsigned long checksum;
324 unsigned char *checksum_ptr;
325 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
326 int error; ///< contains the error code or 0 if no error happened
327 int (*read_pause)(void *opaque, int pause);
328 int64_t (*read_seek)(void *opaque, int stream_index,
329 int64_t timestamp, int flags);
332 int init_put_byte(ByteIOContext *s,
333 unsigned char *buffer,
337 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
338 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
339 int64_t (*seek)(void *opaque, int64_t offset, int whence));
340 ByteIOContext *av_alloc_put_byte(
341 unsigned char *buffer,
345 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
346 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
347 int64_t (*seek)(void *opaque, int64_t offset, int whence));
349 void put_byte(ByteIOContext *s, int b);
350 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
351 void put_le64(ByteIOContext *s, uint64_t val);
352 void put_be64(ByteIOContext *s, uint64_t val);
353 void put_le32(ByteIOContext *s, unsigned int val);
354 void put_be32(ByteIOContext *s, unsigned int val);
355 void put_le24(ByteIOContext *s, unsigned int val);
356 void put_be24(ByteIOContext *s, unsigned int val);
357 void put_le16(ByteIOContext *s, unsigned int val);
358 void put_be16(ByteIOContext *s, unsigned int val);
359 void put_tag(ByteIOContext *s, const char *tag);
361 void put_strz(ByteIOContext *s, const char *buf);
364 * fseek() equivalent for ByteIOContext.
365 * @return new position or AVERROR.
367 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
370 * Skip given number of bytes forward.
371 * @param offset number of bytes
372 * @return 0 on success, <0 on error
374 int url_fskip(ByteIOContext *s, int64_t offset);
377 * ftell() equivalent for ByteIOContext.
378 * @return position or AVERROR.
380 int64_t url_ftell(ByteIOContext *s);
384 * @return filesize or AVERROR
386 int64_t url_fsize(ByteIOContext *s);
389 * feof() equivalent for ByteIOContext.
390 * @return non zero if and only if end of file
392 int url_feof(ByteIOContext *s);
394 int url_ferror(ByteIOContext *s);
396 int av_url_read_fpause(ByteIOContext *h, int pause);
397 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
398 int64_t timestamp, int flags);
401 /** @note return URL_EOF (-1) if EOF */
402 int url_fgetc(ByteIOContext *s);
404 /** @warning currently size is limited */
406 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
408 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
411 /** @note unlike fgets, the EOL character is not returned and a whole
412 line is parsed. return NULL if first char read was EOF */
413 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
415 void put_flush_packet(ByteIOContext *s);
419 * Read size bytes from ByteIOContext into buf.
420 * @return number of bytes read or AVERROR
422 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
425 * Read size bytes from ByteIOContext into buf.
426 * This reads at most 1 packet. If that is not enough fewer bytes will be
428 * @return number of bytes read or AVERROR
430 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
432 /** @note return 0 if EOF, so you cannot use it if EOF handling is
434 int get_byte(ByteIOContext *s);
435 unsigned int get_le24(ByteIOContext *s);
436 unsigned int get_le32(ByteIOContext *s);
437 uint64_t get_le64(ByteIOContext *s);
438 unsigned int get_le16(ByteIOContext *s);
440 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
441 unsigned int get_be16(ByteIOContext *s);
442 unsigned int get_be24(ByteIOContext *s);
443 unsigned int get_be32(ByteIOContext *s);
444 uint64_t get_be64(ByteIOContext *s);
446 uint64_t ff_get_v(ByteIOContext *bc);
448 static inline int url_is_streamed(ByteIOContext *s)
450 return s->is_streamed;
454 * Create and initialize a ByteIOContext for accessing the
455 * resource referenced by the URLContext h.
456 * @note When the URLContext h has been opened in read+write mode, the
457 * ByteIOContext can be used only for writing.
459 * @param s Used to return the pointer to the created ByteIOContext.
460 * In case of failure the pointed to value is set to NULL.
461 * @return 0 in case of success, a negative value corresponding to an
462 * AVERROR code in case of failure
464 int url_fdopen(ByteIOContext **s, URLContext *h);
466 /** @warning must be called before any I/O */
467 int url_setbufsize(ByteIOContext *s, int buf_size);
468 #if FF_API_URL_RESETBUF
469 /** Reset the buffer for reading or writing.
470 * @note Will drop any data currently in the buffer without transmitting it.
471 * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
472 * to set up the buffer for writing. */
473 int url_resetbuf(ByteIOContext *s, int flags);
477 * Rewind the ByteIOContext using the specified buffer containing the first buf_size bytes of the file.
478 * Used after probing to avoid seeking.
479 * Joins buf and s->buffer, taking any overlap into consideration.
480 * @note s->buffer must overlap with buf or they can't be joined and the function fails
481 * @note This function is NOT part of the public API
483 * @param s The read-only ByteIOContext to rewind
484 * @param buf The probe buffer containing the first buf_size bytes of the file
485 * @param buf_size The size of buf
486 * @return 0 in case of success, a negative value corresponding to an
487 * AVERROR code in case of failure
489 int ff_rewind_with_probe_data(ByteIOContext *s, unsigned char *buf, int buf_size);
492 * Create and initialize a ByteIOContext for accessing the
493 * resource indicated by url.
494 * @note When the resource indicated by url has been opened in
495 * read+write mode, the ByteIOContext can be used only for writing.
497 * @param s Used to return the pointer to the created ByteIOContext.
498 * In case of failure the pointed to value is set to NULL.
499 * @param flags flags which control how the resource indicated by url
501 * @return 0 in case of success, a negative value corresponding to an
502 * AVERROR code in case of failure
504 int url_fopen(ByteIOContext **s, const char *url, int flags);
506 int url_fclose(ByteIOContext *s);
507 URLContext *url_fileno(ByteIOContext *s);
510 * Return the maximum packet size associated to packetized buffered file
511 * handle. If the file is not packetized (stream like http or file on
512 * disk), then 0 is returned.
514 * @param s buffered file handle
515 * @return maximum packet size in bytes
517 int url_fget_max_packet_size(ByteIOContext *s);
519 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
521 /** return the written or read size */
522 int url_close_buf(ByteIOContext *s);
525 * Open a write only memory stream.
527 * @param s new IO context
528 * @return zero if no error.
530 int url_open_dyn_buf(ByteIOContext **s);
533 * Open a write only packetized memory stream with a maximum packet
534 * size of 'max_packet_size'. The stream is stored in a memory buffer
535 * with a big endian 4 byte header giving the packet size in bytes.
537 * @param s new IO context
538 * @param max_packet_size maximum packet size (must be > 0)
539 * @return zero if no error.
541 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
544 * Return the written size and a pointer to the buffer. The buffer
545 * must be freed with av_free(). If the buffer is opened with
546 * url_open_dyn_buf, then padding of FF_INPUT_BUFFER_PADDING_SIZE is
547 * added; if opened with url_open_dyn_packet_buf, no padding is added.
549 * @param s IO context
550 * @param pbuffer pointer to a byte buffer
551 * @return the length of the byte buffer
553 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
555 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
557 unsigned long get_checksum(ByteIOContext *s);
558 void init_checksum(ByteIOContext *s,
559 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
560 unsigned long checksum);
563 int udp_set_remote_url(URLContext *h, const char *uri);
564 int udp_get_local_port(URLContext *h);
565 #if FF_API_UDP_GET_FILE
566 int udp_get_file_handle(URLContext *h);
569 #endif /* AVFORMAT_AVIO_H */