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);
137 * Write size bytes from buf to the resource accessed by h.
139 * @return the number of bytes actually written, or a negative value
140 * corresponding to an AVERROR code in case of failure
142 int url_write(URLContext *h, const unsigned char *buf, int size);
145 * Passing this as the "whence" parameter to a seek function causes it to
146 * return the filesize without seeking anywhere. Supporting this is optional.
147 * If it is not supported then the seek function will return <0.
149 #define AVSEEK_SIZE 0x10000
152 * Change the position that will be used by the next read/write
153 * operation on the resource accessed by h.
155 * @param pos specifies the new position to set
156 * @param whence specifies how pos should be interpreted, it must be
157 * one of SEEK_SET (seek from the beginning), SEEK_CUR (seek from the
158 * current position), SEEK_END (seek from the end), or AVSEEK_SIZE
159 * (return the filesize of the requested resource, pos is ignored).
160 * @return a negative value corresponding to an AVERROR code in case
161 * of failure, or the resulting file position, measured in bytes from
162 * the beginning of the file. You can use this feature together with
163 * SEEK_CUR to read the current file position.
165 int64_t url_seek(URLContext *h, int64_t pos, int whence);
168 * Close the resource accessed by the URLContext h, and free the
171 * @return a negative value if an error condition occurred, 0
174 int url_close(URLContext *h);
177 * Return a non-zero value if the resource indicated by url
178 * exists, 0 otherwise.
180 int url_exist(const char *url);
183 * Return the filesize of the resource accessed by h, AVERROR(ENOSYS)
184 * if the operation is not supported by h, or another negative value
185 * corresponding to an AVERROR error code in case of failure.
187 int64_t url_filesize(URLContext *h);
190 * Return the file descriptor associated with this URL. For RTP, this
191 * will return only the RTP file descriptor, not the RTCP file descriptor.
193 * @return the file descriptor associated with this URL, or <0 on error.
195 int url_get_file_handle(URLContext *h);
198 * Return the maximum packet size associated to packetized file
199 * handle. If the file is not packetized (stream like HTTP or file on
200 * disk), then 0 is returned.
202 * @param h file handle
203 * @return maximum packet size in bytes
205 int url_get_max_packet_size(URLContext *h);
208 * Copy the filename of the resource accessed by h to buf.
210 * @param buf_size size in bytes of buf
212 void url_get_filename(URLContext *h, char *buf, int buf_size);
215 * The callback is called in blocking functions to test regulary if
216 * asynchronous interruption is needed. AVERROR(EINTR) is returned
217 * in this case by the interrupted function. 'NULL' means no interrupt
220 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
222 /* not implemented */
223 int url_poll(URLPollEntry *poll_table, int n, int timeout);
226 * Pause and resume playing - only meaningful if using a network streaming
227 * protocol (e.g. MMS).
228 * @param pause 1 for pause, 0 for resume
230 int av_url_read_pause(URLContext *h, int pause);
233 * Seek to a given timestamp relative to some component stream.
234 * Only meaningful if using a network streaming protocol (e.g. MMS.).
235 * @param stream_index The stream index that the timestamp is relative to.
236 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
237 * units from the beginning of the presentation.
238 * If a stream_index >= 0 is used and the protocol does not support
239 * seeking based on component streams, the call will fail with ENOTSUP.
240 * @param timestamp timestamp in AVStream.time_base units
241 * or if there is no stream specified then in AV_TIME_BASE units.
242 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
243 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
244 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
245 * fail with ENOTSUP if used and not supported.
246 * @return >= 0 on success
247 * @see AVInputFormat::read_seek
249 int64_t av_url_read_seek(URLContext *h, int stream_index,
250 int64_t timestamp, int flags);
253 * Oring this flag as into the "whence" parameter to a seek function causes it to
254 * seek by any means (like reopening and linear reading) or other normally unreasonble
255 * means that can be extreemly slow.
256 * This may be ignored by the seek code.
258 #define AVSEEK_FORCE 0x20000
260 typedef struct URLProtocol {
262 int (*url_open)(URLContext *h, const char *url, int flags);
263 int (*url_read)(URLContext *h, unsigned char *buf, int size);
264 int (*url_write)(URLContext *h, const unsigned char *buf, int size);
265 int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
266 int (*url_close)(URLContext *h);
267 struct URLProtocol *next;
268 int (*url_read_pause)(URLContext *h, int pause);
269 int64_t (*url_read_seek)(URLContext *h, int stream_index,
270 int64_t timestamp, int flags);
271 int (*url_get_file_handle)(URLContext *h);
273 const AVClass *priv_data_class;
276 #if FF_API_REGISTER_PROTOCOL
277 extern URLProtocol *first_protocol;
280 extern URLInterruptCB *url_interrupt_cb;
283 * If protocol is NULL, returns the first registered protocol,
284 * if protocol is non-NULL, returns the next registered protocol after protocol,
285 * or NULL if protocol is the last one.
287 URLProtocol *av_protocol_next(URLProtocol *p);
289 #if FF_API_REGISTER_PROTOCOL
291 * @deprecated Use av_register_protocol() instead.
293 attribute_deprecated int register_protocol(URLProtocol *protocol);
296 * @deprecated Use av_register_protocol2() instead.
298 attribute_deprecated int av_register_protocol(URLProtocol *protocol);
302 * Register the URLProtocol protocol.
304 * @param size the size of the URLProtocol struct referenced
306 int av_register_protocol2(URLProtocol *protocol, int size);
309 * Bytestream IO Context.
310 * New fields can be added to the end with minor version bumps.
311 * Removal, reordering and changes to existing fields require a major
313 * sizeof(ByteIOContext) must not be used outside libav*.
316 unsigned char *buffer;
318 unsigned char *buf_ptr, *buf_end;
320 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
321 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
322 int64_t (*seek)(void *opaque, int64_t offset, int whence);
323 int64_t pos; /**< position in the file of the current buffer */
324 int must_flush; /**< true if the next seek should flush */
325 int eof_reached; /**< true if eof reached */
326 int write_flag; /**< true if open for writing */
329 unsigned long checksum;
330 unsigned char *checksum_ptr;
331 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
332 int error; ///< contains the error code or 0 if no error happened
333 int (*read_pause)(void *opaque, int pause);
334 int64_t (*read_seek)(void *opaque, int stream_index,
335 int64_t timestamp, int flags);
338 int init_put_byte(ByteIOContext *s,
339 unsigned char *buffer,
343 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
344 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
345 int64_t (*seek)(void *opaque, int64_t offset, int whence));
346 ByteIOContext *av_alloc_put_byte(
347 unsigned char *buffer,
351 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
352 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
353 int64_t (*seek)(void *opaque, int64_t offset, int whence));
355 void put_byte(ByteIOContext *s, int b);
356 void put_nbyte(ByteIOContext *s, int b, int count);
357 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
358 void put_le64(ByteIOContext *s, uint64_t val);
359 void put_be64(ByteIOContext *s, uint64_t val);
360 void put_le32(ByteIOContext *s, unsigned int val);
361 void put_be32(ByteIOContext *s, unsigned int val);
362 void put_le24(ByteIOContext *s, unsigned int val);
363 void put_be24(ByteIOContext *s, unsigned int val);
364 void put_le16(ByteIOContext *s, unsigned int val);
365 void put_be16(ByteIOContext *s, unsigned int val);
366 void put_tag(ByteIOContext *s, const char *tag);
368 void put_strz(ByteIOContext *s, const char *buf);
371 * fseek() equivalent for ByteIOContext.
372 * @return new position or AVERROR.
374 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
377 * Skip given number of bytes forward.
378 * @param offset number of bytes
379 * @return 0 on success, <0 on error
381 int url_fskip(ByteIOContext *s, int64_t offset);
384 * ftell() equivalent for ByteIOContext.
385 * @return position or AVERROR.
387 int64_t url_ftell(ByteIOContext *s);
391 * @return filesize or AVERROR
393 int64_t url_fsize(ByteIOContext *s);
396 * feof() equivalent for ByteIOContext.
397 * @return non zero if and only if end of file
399 int url_feof(ByteIOContext *s);
401 int url_ferror(ByteIOContext *s);
403 int av_url_read_fpause(ByteIOContext *h, int pause);
404 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
405 int64_t timestamp, int flags);
408 /** @note return URL_EOF (-1) if EOF */
409 int url_fgetc(ByteIOContext *s);
411 /** @warning currently size is limited */
413 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
415 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
418 /** @note unlike fgets, the EOL character is not returned and a whole
419 line is parsed. return NULL if first char read was EOF */
420 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
422 void put_flush_packet(ByteIOContext *s);
426 * Read size bytes from ByteIOContext into buf.
427 * @return number of bytes read or AVERROR
429 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
432 * Read size bytes from ByteIOContext into buf.
433 * This reads at most 1 packet. If that is not enough fewer bytes will be
435 * @return number of bytes read or AVERROR
437 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
439 /** @note return 0 if EOF, so you cannot use it if EOF handling is
441 int get_byte(ByteIOContext *s);
442 unsigned int get_le24(ByteIOContext *s);
443 unsigned int get_le32(ByteIOContext *s);
444 uint64_t get_le64(ByteIOContext *s);
445 unsigned int get_le16(ByteIOContext *s);
447 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
448 unsigned int get_be16(ByteIOContext *s);
449 unsigned int get_be24(ByteIOContext *s);
450 unsigned int get_be32(ByteIOContext *s);
451 uint64_t get_be64(ByteIOContext *s);
453 uint64_t ff_get_v(ByteIOContext *bc);
455 static inline int url_is_streamed(ByteIOContext *s)
457 return s->is_streamed;
461 * Create and initialize a ByteIOContext for accessing the
462 * resource referenced by the URLContext h.
463 * @note When the URLContext h has been opened in read+write mode, the
464 * ByteIOContext can be used only for writing.
466 * @param s Used to return the pointer to the created ByteIOContext.
467 * In case of failure the pointed to value is set to NULL.
468 * @return 0 in case of success, a negative value corresponding to an
469 * AVERROR code in case of failure
471 int url_fdopen(ByteIOContext **s, URLContext *h);
473 /** @warning must be called before any I/O */
474 int url_setbufsize(ByteIOContext *s, int buf_size);
475 #if FF_API_URL_RESETBUF
476 /** Reset the buffer for reading or writing.
477 * @note Will drop any data currently in the buffer without transmitting it.
478 * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
479 * to set up the buffer for writing. */
480 int url_resetbuf(ByteIOContext *s, int flags);
484 * Rewind the ByteIOContext using the specified buffer containing the first buf_size bytes of the file.
485 * Used after probing to avoid seeking.
486 * Joins buf and s->buffer, taking any overlap into consideration.
487 * @note s->buffer must overlap with buf or they can't be joined and the function fails
488 * @note This function is NOT part of the public API
490 * @param s The read-only ByteIOContext to rewind
491 * @param buf The probe buffer containing the first buf_size bytes of the file
492 * @param buf_size The size of buf
493 * @return 0 in case of success, a negative value corresponding to an
494 * AVERROR code in case of failure
496 int ff_rewind_with_probe_data(ByteIOContext *s, unsigned char *buf, int buf_size);
499 * Create and initialize a ByteIOContext for accessing the
500 * resource indicated by url.
501 * @note When the resource indicated by url has been opened in
502 * read+write mode, the ByteIOContext can be used only for writing.
504 * @param s Used to return the pointer to the created ByteIOContext.
505 * In case of failure the pointed to value is set to NULL.
506 * @param flags flags which control how the resource indicated by url
508 * @return 0 in case of success, a negative value corresponding to an
509 * AVERROR code in case of failure
511 int url_fopen(ByteIOContext **s, const char *url, int flags);
513 int url_fclose(ByteIOContext *s);
514 URLContext *url_fileno(ByteIOContext *s);
517 * Return the maximum packet size associated to packetized buffered file
518 * handle. If the file is not packetized (stream like http or file on
519 * disk), then 0 is returned.
521 * @param s buffered file handle
522 * @return maximum packet size in bytes
524 int url_fget_max_packet_size(ByteIOContext *s);
526 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
528 /** return the written or read size */
529 int url_close_buf(ByteIOContext *s);
532 * Open a write only memory stream.
534 * @param s new IO context
535 * @return zero if no error.
537 int url_open_dyn_buf(ByteIOContext **s);
540 * Open a write only packetized memory stream with a maximum packet
541 * size of 'max_packet_size'. The stream is stored in a memory buffer
542 * with a big endian 4 byte header giving the packet size in bytes.
544 * @param s new IO context
545 * @param max_packet_size maximum packet size (must be > 0)
546 * @return zero if no error.
548 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
551 * Return the written size and a pointer to the buffer. The buffer
552 * must be freed with av_free(). If the buffer is opened with
553 * url_open_dyn_buf, then padding of FF_INPUT_BUFFER_PADDING_SIZE is
554 * added; if opened with url_open_dyn_packet_buf, no padding is added.
556 * @param s IO context
557 * @param pbuffer pointer to a byte buffer
558 * @return the length of the byte buffer
560 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
562 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
564 unsigned long get_checksum(ByteIOContext *s);
565 void init_checksum(ByteIOContext *s,
566 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
567 unsigned long checksum);
570 int udp_set_remote_url(URLContext *h, const char *uri);
571 int udp_get_local_port(URLContext *h);
572 #if FF_API_UDP_GET_FILE
573 int udp_get_file_handle(URLContext *h);
576 #endif /* AVFORMAT_AVIO_H */