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
24 * @file libavformat/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 filename */
56 typedef struct URLPollEntry {
66 typedef int URLInterruptCB(void);
69 * Creates an URLContext for accessing to the resource indicated by
70 * filename, 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 filename
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 *filename, int flags);
82 int url_open(URLContext **h, const char *filename, int flags);
85 * Reads up to size bytes from the resource accessed by h, and stores
86 * the read bytes in buf.
88 * @return The number of bytes actually read, or a negative value
89 * corresponding to an AVERROR code in case of error. A value of zero
90 * indicates that it is not possible to read more from the accessed
91 * resource (except if the value of the size argument is also zero).
93 int url_read(URLContext *h, unsigned char *buf, int size);
96 * Read as many bytes as possible (up to size), calling the
97 * read function multiple times if necessary.
98 * Will also retry if the read function returns AVERROR(EAGAIN).
99 * This makes special short-read handling in applications
100 * unnecessary, if the return value is < size then it is
101 * certain there was either an error or the end of file was reached.
103 int url_read_complete(URLContext *h, unsigned char *buf, int size);
104 int url_write(URLContext *h, unsigned char *buf, int size);
105 int64_t url_seek(URLContext *h, int64_t pos, int whence);
108 * Closes the resource accessed by the URLContext h, and frees the
111 * @return a negative value if an error condition occurred, 0
114 int url_close(URLContext *h);
116 int url_exist(const char *filename);
117 int64_t url_filesize(URLContext *h);
120 * Return the file descriptor associated with this URL. For RTP, this
121 * will return only the RTP file descriptor, not the RTCP file descriptor.
122 * To get both, use rtp_get_file_handles().
124 * @return the file descriptor associated with this URL, or <0 on error.
126 int url_get_file_handle(URLContext *h);
129 * Return the maximum packet size associated to packetized file
130 * handle. If the file is not packetized (stream like HTTP or file on
131 * disk), then 0 is returned.
133 * @param h file handle
134 * @return maximum packet size in bytes
136 int url_get_max_packet_size(URLContext *h);
137 void url_get_filename(URLContext *h, char *buf, int buf_size);
140 * The callback is called in blocking functions to test regulary if
141 * asynchronous interruption is needed. AVERROR(EINTR) is returned
142 * in this case by the interrupted function. 'NULL' means no interrupt
145 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
147 /* not implemented */
148 int url_poll(URLPollEntry *poll_table, int n, int timeout);
151 * Pause and resume playing - only meaningful if using a network streaming
152 * protocol (e.g. MMS).
153 * @param pause 1 for pause, 0 for resume
155 int av_url_read_pause(URLContext *h, int pause);
158 * Seek to a given timestamp relative to some component stream.
159 * Only meaningful if using a network streaming protocol (e.g. MMS.).
160 * @param stream_index The stream index that the timestamp is relative to.
161 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
162 * units from the beginning of the presentation.
163 * If a stream_index >= 0 is used and the protocol does not support
164 * seeking based on component streams, the call will fail with ENOTSUP.
165 * @param timestamp timestamp in AVStream.time_base units
166 * or if there is no stream specified then in AV_TIME_BASE units.
167 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
168 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
169 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
170 * fail with ENOTSUP if used and not supported.
171 * @return >= 0 on success
172 * @see AVInputFormat::read_seek
174 int64_t av_url_read_seek(URLContext *h, int stream_index,
175 int64_t timestamp, int flags);
178 * Passing this as the "whence" parameter to a seek function causes it to
179 * return the filesize without seeking anywhere. Supporting this is optional.
180 * If it is not supported then the seek function will return <0.
182 #define AVSEEK_SIZE 0x10000
184 typedef struct URLProtocol {
186 int (*url_open)(URLContext *h, const char *filename, int flags);
187 int (*url_read)(URLContext *h, unsigned char *buf, int size);
188 int (*url_write)(URLContext *h, unsigned char *buf, int size);
189 int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
190 int (*url_close)(URLContext *h);
191 struct URLProtocol *next;
192 int (*url_read_pause)(URLContext *h, int pause);
193 int64_t (*url_read_seek)(URLContext *h, int stream_index,
194 int64_t timestamp, int flags);
195 int (*url_get_file_handle)(URLContext *h);
198 #if LIBAVFORMAT_VERSION_MAJOR < 53
199 extern URLProtocol *first_protocol;
202 extern URLInterruptCB *url_interrupt_cb;
205 * If protocol is NULL, returns the first registered protocol,
206 * if protocol is non-NULL, returns the next registered protocol after protocol,
207 * or NULL if protocol is the last one.
209 URLProtocol *av_protocol_next(URLProtocol *p);
211 #if LIBAVFORMAT_VERSION_MAJOR < 53
213 * @deprecated Use av_register_protocol() instead.
215 attribute_deprecated int register_protocol(URLProtocol *protocol);
218 int av_register_protocol(URLProtocol *protocol);
221 * Bytestream IO Context.
222 * New fields can be added to the end with minor version bumps.
223 * Removal, reordering and changes to existing fields require a major
225 * sizeof(ByteIOContext) must not be used outside libav*.
228 unsigned char *buffer;
230 unsigned char *buf_ptr, *buf_end;
232 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
233 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
234 int64_t (*seek)(void *opaque, int64_t offset, int whence);
235 int64_t pos; /**< position in the file of the current buffer */
236 int must_flush; /**< true if the next seek should flush */
237 int eof_reached; /**< true if eof reached */
238 int write_flag; /**< true if open for writing */
241 unsigned long checksum;
242 unsigned char *checksum_ptr;
243 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
244 int error; ///< contains the error code or 0 if no error happened
245 int (*read_pause)(void *opaque, int pause);
246 int64_t (*read_seek)(void *opaque, int stream_index,
247 int64_t timestamp, int flags);
250 int init_put_byte(ByteIOContext *s,
251 unsigned char *buffer,
255 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
256 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
257 int64_t (*seek)(void *opaque, int64_t offset, int whence));
258 ByteIOContext *av_alloc_put_byte(
259 unsigned char *buffer,
263 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
264 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
265 int64_t (*seek)(void *opaque, int64_t offset, int whence));
267 void put_byte(ByteIOContext *s, int b);
268 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
269 void put_le64(ByteIOContext *s, uint64_t val);
270 void put_be64(ByteIOContext *s, uint64_t val);
271 void put_le32(ByteIOContext *s, unsigned int val);
272 void put_be32(ByteIOContext *s, unsigned int val);
273 void put_le24(ByteIOContext *s, unsigned int val);
274 void put_be24(ByteIOContext *s, unsigned int val);
275 void put_le16(ByteIOContext *s, unsigned int val);
276 void put_be16(ByteIOContext *s, unsigned int val);
277 void put_tag(ByteIOContext *s, const char *tag);
279 void put_strz(ByteIOContext *s, const char *buf);
282 * fseek() equivalent for ByteIOContext.
283 * @return new position or AVERROR.
285 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
288 * Skip given number of bytes forward.
289 * @param offset number of bytes
291 void url_fskip(ByteIOContext *s, int64_t offset);
294 * ftell() equivalent for ByteIOContext.
295 * @return position or AVERROR.
297 int64_t url_ftell(ByteIOContext *s);
301 * @return filesize or AVERROR
303 int64_t url_fsize(ByteIOContext *s);
306 * feof() equivalent for ByteIOContext.
307 * @return non zero if and only if end of file
309 int url_feof(ByteIOContext *s);
311 int url_ferror(ByteIOContext *s);
313 int av_url_read_fpause(ByteIOContext *h, int pause);
314 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
315 int64_t timestamp, int flags);
318 /** @note return URL_EOF (-1) if EOF */
319 int url_fgetc(ByteIOContext *s);
321 /** @warning currently size is limited */
323 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
325 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
328 /** @note unlike fgets, the EOL character is not returned and a whole
329 line is parsed. return NULL if first char read was EOF */
330 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
332 void put_flush_packet(ByteIOContext *s);
336 * Reads size bytes from ByteIOContext into buf.
337 * @returns number of bytes read or AVERROR
339 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
342 * Reads size bytes from ByteIOContext into buf.
343 * This reads at most 1 packet. If that is not enough fewer bytes will be
345 * @returns number of bytes read or AVERROR
347 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
349 /** @note return 0 if EOF, so you cannot use it if EOF handling is
351 int get_byte(ByteIOContext *s);
352 unsigned int get_le24(ByteIOContext *s);
353 unsigned int get_le32(ByteIOContext *s);
354 uint64_t get_le64(ByteIOContext *s);
355 unsigned int get_le16(ByteIOContext *s);
357 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
358 unsigned int get_be16(ByteIOContext *s);
359 unsigned int get_be24(ByteIOContext *s);
360 unsigned int get_be32(ByteIOContext *s);
361 uint64_t get_be64(ByteIOContext *s);
363 uint64_t ff_get_v(ByteIOContext *bc);
365 static inline int url_is_streamed(ByteIOContext *s)
367 return s->is_streamed;
370 /** @note when opened as read/write, the buffers are only used for
372 int url_fdopen(ByteIOContext **s, URLContext *h);
374 /** @warning must be called before any I/O */
375 int url_setbufsize(ByteIOContext *s, int buf_size);
376 #if LIBAVFORMAT_VERSION_MAJOR < 53
377 /** Reset the buffer for reading or writing.
378 * @note Will drop any data currently in the buffer without transmitting it.
379 * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
380 * to set up the buffer for writing. */
381 int url_resetbuf(ByteIOContext *s, int flags);
384 /** @note when opened as read/write, the buffers are only used for
386 int url_fopen(ByteIOContext **s, const char *filename, int flags);
387 int url_fclose(ByteIOContext *s);
388 URLContext *url_fileno(ByteIOContext *s);
391 * Return the maximum packet size associated to packetized buffered file
392 * handle. If the file is not packetized (stream like http or file on
393 * disk), then 0 is returned.
395 * @param s buffered file handle
396 * @return maximum packet size in bytes
398 int url_fget_max_packet_size(ByteIOContext *s);
400 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
402 /** return the written or read size */
403 int url_close_buf(ByteIOContext *s);
406 * Open a write only memory stream.
408 * @param s new IO context
409 * @return zero if no error.
411 int url_open_dyn_buf(ByteIOContext **s);
414 * Open a write only packetized memory stream with a maximum packet
415 * size of 'max_packet_size'. The stream is stored in a memory buffer
416 * with a big endian 4 byte header giving the packet size in bytes.
418 * @param s new IO context
419 * @param max_packet_size maximum packet size (must be > 0)
420 * @return zero if no error.
422 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
425 * Return the written size and a pointer to the buffer. The buffer
426 * must be freed with av_free().
427 * @param s IO context
428 * @param pbuffer pointer to a byte buffer
429 * @return the length of the byte buffer
431 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
433 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
435 unsigned long get_checksum(ByteIOContext *s);
436 void init_checksum(ByteIOContext *s,
437 unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
438 unsigned long checksum);
441 int udp_set_remote_url(URLContext *h, const char *uri);
442 int udp_get_local_port(URLContext *h);
443 #if (LIBAVFORMAT_VERSION_MAJOR <= 52)
444 int udp_get_file_handle(URLContext *h);
447 #endif /* AVFORMAT_AVIO_H */