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"
36 #include "libavformat/version.h"
42 * New fields can be added to the end with minor version bumps.
43 * Removal, reordering and changes to existing fields require a major
45 * sizeof(URLContext) must not be used outside libav*.
47 typedef struct URLContext {
49 const AVClass *av_class; ///< information for av_log(). Set by url_open().
51 struct URLProtocol *prot;
53 int is_streamed; /**< true if streamed (no seek possible), default = false */
54 int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
56 char *filename; /**< specified URL */
60 typedef struct URLPollEntry {
70 typedef int URLInterruptCB(void);
73 * Create a URLContext for accessing to the resource indicated by
74 * url, and open it using the URLProtocol up.
76 * @param puc pointer to the location where, in case of success, the
77 * function puts the pointer to the created URLContext
78 * @param flags flags which control how the resource indicated by url
80 * @return 0 in case of success, a negative value corresponding to an
81 * AVERROR code in case of failure
83 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
84 const char *url, int flags);
87 * Create a URLContext for accessing to the resource indicated by
88 * url, but do not initiate the connection yet.
90 * @param puc pointer to the location where, in case of success, the
91 * function puts the pointer to the created URLContext
92 * @param flags flags which control how the resource indicated by url
94 * @return 0 in case of success, a negative value corresponding to an
95 * AVERROR code in case of failure
97 int url_alloc(URLContext **h, const char *url, int flags);
100 * Connect an URLContext that has been allocated by url_alloc
102 int url_connect(URLContext *h);
105 * Create an URLContext for accessing to the resource indicated by
108 * @param puc pointer to the location where, in case of success, the
109 * function puts the pointer to the created URLContext
110 * @param flags flags which control how the resource indicated by url
112 * @return 0 in case of success, a negative value corresponding to an
113 * AVERROR code in case of failure
115 int url_open(URLContext **h, const char *url, int flags);
118 * Read up to size bytes from the resource accessed by h, and store
119 * the read bytes in buf.
121 * @return The number of bytes actually read, or a negative value
122 * corresponding to an AVERROR code in case of error. A value of zero
123 * indicates that it is not possible to read more from the accessed
124 * resource (except if the value of the size argument is also zero).
126 int url_read(URLContext *h, unsigned char *buf, int size);
129 * Read as many bytes as possible (up to size), calling the
130 * read function multiple times if necessary.
131 * Will also retry if the read function returns AVERROR(EAGAIN).
132 * This makes special short-read handling in applications
133 * unnecessary, if the return value is < size then it is
134 * certain there was either an error or the end of file was reached.
136 int url_read_complete(URLContext *h, unsigned char *buf, int size);
139 * Write size bytes from buf to the resource accessed by h.
141 * @return the number of bytes actually written, or a negative value
142 * corresponding to an AVERROR code in case of failure
144 int url_write(URLContext *h, const unsigned char *buf, int size);
147 * Passing this as the "whence" parameter to a seek function causes it to
148 * return the filesize without seeking anywhere. Supporting this is optional.
149 * If it is not supported then the seek function will return <0.
151 #define AVSEEK_SIZE 0x10000
154 * Change the position that will be used by the next read/write
155 * operation on the resource accessed by h.
157 * @param pos specifies the new position to set
158 * @param whence specifies how pos should be interpreted, it must be
159 * one of SEEK_SET (seek from the beginning), SEEK_CUR (seek from the
160 * current position), SEEK_END (seek from the end), or AVSEEK_SIZE
161 * (return the filesize of the requested resource, pos is ignored).
162 * @return a negative value corresponding to an AVERROR code in case
163 * of failure, or the resulting file position, measured in bytes from
164 * the beginning of the file. You can use this feature together with
165 * SEEK_CUR to read the current file position.
167 int64_t url_seek(URLContext *h, int64_t pos, int whence);
170 * Close the resource accessed by the URLContext h, and free the
173 * @return a negative value if an error condition occurred, 0
176 int url_close(URLContext *h);
179 * Return a non-zero value if the resource indicated by url
180 * exists, 0 otherwise.
182 int url_exist(const char *url);
185 * Return the filesize of the resource accessed by h, AVERROR(ENOSYS)
186 * if the operation is not supported by h, or another negative value
187 * corresponding to an AVERROR error code in case of failure.
189 int64_t url_filesize(URLContext *h);
192 * Return the file descriptor associated with this URL. For RTP, this
193 * will return only the RTP file descriptor, not the RTCP file descriptor.
195 * @return the file descriptor associated with this URL, or <0 on error.
197 int url_get_file_handle(URLContext *h);
200 * Return the maximum packet size associated to packetized file
201 * handle. If the file is not packetized (stream like HTTP or file on
202 * disk), then 0 is returned.
204 * @param h file handle
205 * @return maximum packet size in bytes
207 int url_get_max_packet_size(URLContext *h);
210 * Copy the filename of the resource accessed by h to buf.
212 * @param buf_size size in bytes of buf
214 void url_get_filename(URLContext *h, char *buf, int buf_size);
217 * The callback is called in blocking functions to test regulary if
218 * asynchronous interruption is needed. AVERROR(EINTR) is returned
219 * in this case by the interrupted function. 'NULL' means no interrupt
222 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
224 /* not implemented */
225 int url_poll(URLPollEntry *poll_table, int n, int timeout);
228 * Pause and resume playing - only meaningful if using a network streaming
229 * protocol (e.g. MMS).
230 * @param pause 1 for pause, 0 for resume
232 int av_url_read_pause(URLContext *h, int pause);
235 * Seek to a given timestamp relative to some component stream.
236 * Only meaningful if using a network streaming protocol (e.g. MMS.).
237 * @param stream_index The stream index that the timestamp is relative to.
238 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
239 * units from the beginning of the presentation.
240 * If a stream_index >= 0 is used and the protocol does not support
241 * seeking based on component streams, the call will fail with ENOTSUP.
242 * @param timestamp timestamp in AVStream.time_base units
243 * or if there is no stream specified then in AV_TIME_BASE units.
244 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
245 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
246 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
247 * fail with ENOTSUP if used and not supported.
248 * @return >= 0 on success
249 * @see AVInputFormat::read_seek
251 int64_t av_url_read_seek(URLContext *h, int stream_index,
252 int64_t timestamp, int flags);
255 * Oring this flag as into the "whence" parameter to a seek function causes it to
256 * seek by any means (like reopening and linear reading) or other normally unreasonble
257 * means that can be extreemly slow.
258 * This may be ignored by the seek code.
260 #define AVSEEK_FORCE 0x20000
262 typedef struct URLProtocol {
264 int (*url_open)(URLContext *h, const char *url, int flags);
265 int (*url_read)(URLContext *h, unsigned char *buf, int size);
266 int (*url_write)(URLContext *h, const unsigned char *buf, int size);
267 int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
268 int (*url_close)(URLContext *h);
269 struct URLProtocol *next;
270 int (*url_read_pause)(URLContext *h, int pause);
271 int64_t (*url_read_seek)(URLContext *h, int stream_index,
272 int64_t timestamp, int flags);
273 int (*url_get_file_handle)(URLContext *h);
275 const AVClass *priv_data_class;
278 #if FF_API_REGISTER_PROTOCOL
279 extern URLProtocol *first_protocol;
282 extern URLInterruptCB *url_interrupt_cb;
285 * If protocol is NULL, returns the first registered protocol,
286 * if protocol is non-NULL, returns the next registered protocol after protocol,
287 * or NULL if protocol is the last one.
289 URLProtocol *av_protocol_next(URLProtocol *p);
291 #if FF_API_REGISTER_PROTOCOL
293 * @deprecated Use av_register_protocol() instead.
295 attribute_deprecated int register_protocol(URLProtocol *protocol);
298 * @deprecated Use av_register_protocol2() instead.
300 attribute_deprecated int av_register_protocol(URLProtocol *protocol);
304 * Register the URLProtocol protocol.
306 * @param size the size of the URLProtocol struct referenced
308 int av_register_protocol2(URLProtocol *protocol, int size);
311 * Bytestream IO Context.
312 * New fields can be added to the end with minor version bumps.
313 * Removal, reordering and changes to existing fields require a major
315 * sizeof(ByteIOContext) must not be used outside libav*.
318 unsigned char *buffer;
320 unsigned char *buf_ptr, *buf_end;
322 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
323 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
324 int64_t (*seek)(void *opaque, int64_t offset, int whence);
325 int64_t pos; /**< position in the file of the current buffer */
326 int must_flush; /**< true if the next seek should flush */
327 int eof_reached; /**< true if eof reached */
328 int write_flag; /**< true if open for writing */
331 unsigned long checksum;
332 unsigned char *checksum_ptr;
333 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
334 int error; ///< contains the error code or 0 if no error happened
335 int (*read_pause)(void *opaque, int pause);
336 int64_t (*read_seek)(void *opaque, int stream_index,
337 int64_t timestamp, int flags);
340 int init_put_byte(ByteIOContext *s,
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));
348 ByteIOContext *av_alloc_put_byte(
349 unsigned char *buffer,
353 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
354 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
355 int64_t (*seek)(void *opaque, int64_t offset, int whence));
357 void put_byte(ByteIOContext *s, int b);
358 void put_nbyte(ByteIOContext *s, int b, int count);
359 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
360 void put_le64(ByteIOContext *s, uint64_t val);
361 void put_be64(ByteIOContext *s, uint64_t val);
362 void put_le32(ByteIOContext *s, unsigned int val);
363 void put_be32(ByteIOContext *s, unsigned int val);
364 void put_le24(ByteIOContext *s, unsigned int val);
365 void put_be24(ByteIOContext *s, unsigned int val);
366 void put_le16(ByteIOContext *s, unsigned int val);
367 void put_be16(ByteIOContext *s, unsigned int val);
368 void put_tag(ByteIOContext *s, const char *tag);
371 attribute_deprecated void put_strz(ByteIOContext *s, const char *buf);
375 * Write a NULL-terminated string.
376 * @return number of bytes written.
378 int avio_put_str(ByteIOContext *s, const char *str);
381 * Convert an UTF-8 string to UTF-16LE and write it.
382 * @return number of bytes written.
384 int avio_put_str16le(ByteIOContext *s, const char *str);
387 * fseek() equivalent for ByteIOContext.
388 * @return new position or AVERROR.
390 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
393 * Skip given number of bytes forward.
394 * @param offset number of bytes
395 * @return 0 on success, <0 on error
397 int url_fskip(ByteIOContext *s, int64_t offset);
400 * ftell() equivalent for ByteIOContext.
401 * @return position or AVERROR.
403 int64_t url_ftell(ByteIOContext *s);
407 * @return filesize or AVERROR
409 int64_t url_fsize(ByteIOContext *s);
412 * feof() equivalent for ByteIOContext.
413 * @return non zero if and only if end of file
415 int url_feof(ByteIOContext *s);
417 int url_ferror(ByteIOContext *s);
419 int av_url_read_fpause(ByteIOContext *h, int pause);
420 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
421 int64_t timestamp, int flags);
424 /** @note return URL_EOF (-1) if EOF */
425 int url_fgetc(ByteIOContext *s);
427 /** @warning currently size is limited */
429 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
431 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
434 /** @note unlike fgets, the EOL character is not returned and a whole
435 line is parsed. return NULL if first char read was EOF */
436 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
438 void put_flush_packet(ByteIOContext *s);
442 * Read size bytes from ByteIOContext into buf.
443 * @return number of bytes read or AVERROR
445 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
448 * Read size bytes from ByteIOContext into buf.
449 * This reads at most 1 packet. If that is not enough fewer bytes will be
451 * @return number of bytes read or AVERROR
453 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
455 /** @note return 0 if EOF, so you cannot use it if EOF handling is
457 int get_byte(ByteIOContext *s);
458 unsigned int get_le24(ByteIOContext *s);
459 unsigned int get_le32(ByteIOContext *s);
460 uint64_t get_le64(ByteIOContext *s);
461 unsigned int get_le16(ByteIOContext *s);
464 * Read a UTF-16 string from pb and convert it to UTF-8.
465 * The reading will terminate when either a null or invalid character was
466 * encountered or maxlen bytes have been read.
467 * @return number of bytes read (is always <= maxlen)
469 int avio_get_str16le(ByteIOContext *pb, int maxlen, char *buf, int buflen);
470 int avio_get_str16be(ByteIOContext *pb, int maxlen, char *buf, int buflen);
472 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
473 unsigned int get_be16(ByteIOContext *s);
474 unsigned int get_be24(ByteIOContext *s);
475 unsigned int get_be32(ByteIOContext *s);
476 uint64_t get_be64(ByteIOContext *s);
478 uint64_t ff_get_v(ByteIOContext *bc);
480 static inline int url_is_streamed(ByteIOContext *s)
482 return s->is_streamed;
486 * Create and initialize a ByteIOContext for accessing the
487 * resource referenced by the URLContext h.
488 * @note When the URLContext h has been opened in read+write mode, the
489 * ByteIOContext can be used only for writing.
491 * @param s Used to return the pointer to the created ByteIOContext.
492 * In case of failure the pointed to value is set to NULL.
493 * @return 0 in case of success, a negative value corresponding to an
494 * AVERROR code in case of failure
496 int url_fdopen(ByteIOContext **s, URLContext *h);
498 /** @warning must be called before any I/O */
499 int url_setbufsize(ByteIOContext *s, int buf_size);
500 #if FF_API_URL_RESETBUF
501 /** Reset the buffer for reading or writing.
502 * @note Will drop any data currently in the buffer without transmitting it.
503 * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
504 * to set up the buffer for writing. */
505 int url_resetbuf(ByteIOContext *s, int flags);
509 * Rewind the ByteIOContext using the specified buffer containing the first buf_size bytes of the file.
510 * Used after probing to avoid seeking.
511 * Joins buf and s->buffer, taking any overlap into consideration.
512 * @note s->buffer must overlap with buf or they can't be joined and the function fails
513 * @note This function is NOT part of the public API
515 * @param s The read-only ByteIOContext to rewind
516 * @param buf The probe buffer containing the first buf_size bytes of the file
517 * @param buf_size The size of buf
518 * @return 0 in case of success, a negative value corresponding to an
519 * AVERROR code in case of failure
521 int ff_rewind_with_probe_data(ByteIOContext *s, unsigned char *buf, int buf_size);
524 * Create and initialize a ByteIOContext for accessing the
525 * resource indicated by url.
526 * @note When the resource indicated by url has been opened in
527 * read+write mode, the ByteIOContext can be used only for writing.
529 * @param s Used to return the pointer to the created ByteIOContext.
530 * In case of failure the pointed to value is set to NULL.
531 * @param flags flags which control how the resource indicated by url
533 * @return 0 in case of success, a negative value corresponding to an
534 * AVERROR code in case of failure
536 int url_fopen(ByteIOContext **s, const char *url, int flags);
538 int url_fclose(ByteIOContext *s);
539 URLContext *url_fileno(ByteIOContext *s);
542 * Return the maximum packet size associated to packetized buffered file
543 * handle. If the file is not packetized (stream like http or file on
544 * disk), then 0 is returned.
546 * @param s buffered file handle
547 * @return maximum packet size in bytes
549 int url_fget_max_packet_size(ByteIOContext *s);
551 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
553 /** return the written or read size */
554 int url_close_buf(ByteIOContext *s);
557 * Open a write only memory stream.
559 * @param s new IO context
560 * @return zero if no error.
562 int url_open_dyn_buf(ByteIOContext **s);
565 * Open a write only packetized memory stream with a maximum packet
566 * size of 'max_packet_size'. The stream is stored in a memory buffer
567 * with a big endian 4 byte header giving the packet size in bytes.
569 * @param s new IO context
570 * @param max_packet_size maximum packet size (must be > 0)
571 * @return zero if no error.
573 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
576 * Return the written size and a pointer to the buffer. The buffer
577 * must be freed with av_free(). If the buffer is opened with
578 * url_open_dyn_buf, then padding of FF_INPUT_BUFFER_PADDING_SIZE is
579 * added; if opened with url_open_dyn_packet_buf, no padding is added.
581 * @param s IO context
582 * @param pbuffer pointer to a byte buffer
583 * @return the length of the byte buffer
585 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
587 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
589 unsigned long get_checksum(ByteIOContext *s);
590 void init_checksum(ByteIOContext *s,
591 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
592 unsigned long checksum);
595 int udp_set_remote_url(URLContext *h, const char *uri);
596 int udp_get_local_port(URLContext *h);
597 #if FF_API_UDP_GET_FILE
598 int udp_get_file_handle(URLContext *h);
601 #endif /* AVFORMAT_AVIO_H */