2 * unbuffered io for ffmpeg system
3 * copyright (c) 2001 Fabrice Bellard
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26 /* output byte stream handling */
28 typedef int64_t offset_t;
34 * New fields can be added to the end with minor version bumps.
35 * Removal, reordering and changes to existing fields require a major
37 * sizeof(URLContext) must not be used outside libav*.
40 struct URLProtocol *prot;
42 int is_streamed; /**< true if streamed (no seek possible), default = false */
43 int max_packet_size; /**< if non zero, the stream is packetized with this max packet size */
45 char *filename; /**< specified filename */
48 typedef struct URLContext URLContext;
50 typedef struct URLPollEntry {
60 typedef int URLInterruptCB(void);
62 int url_open(URLContext **h, const char *filename, int flags);
63 int url_read(URLContext *h, unsigned char *buf, int size);
64 int url_write(URLContext *h, unsigned char *buf, int size);
65 offset_t url_seek(URLContext *h, offset_t pos, int whence);
66 int url_close(URLContext *h);
67 int url_exist(const char *filename);
68 offset_t url_filesize(URLContext *h);
71 * Return the maximum packet size associated to packetized file
72 * handle. If the file is not packetized (stream like HTTP or file on
73 * disk), then 0 is returned.
75 * @param h file handle
76 * @return maximum packet size in bytes
78 int url_get_max_packet_size(URLContext *h);
79 void url_get_filename(URLContext *h, char *buf, int buf_size);
82 * The callback is called in blocking functions to test regulary if
83 * asynchronous interruption is needed. AVERROR(EINTR) is returned
84 * in this case by the interrupted function. 'NULL' means no interrupt
87 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
90 int url_poll(URLPollEntry *poll_table, int n, int timeout);
93 * Pause and resume playing - only meaningful if using a network streaming
94 * protocol (e.g. MMS).
95 * @param pause 1 for pause, 0 for resume
97 int av_url_read_pause(URLContext *h, int pause);
100 * Seek to a given timestamp relative to some component stream.
101 * Only meaningful if using a network streaming protocol (e.g. MMS.).
102 * @param stream_index The stream index that the timestamp is relative to.
103 * If stream_index is (-1) the timestamp should be in AV_TIME_BASE
104 * units from the beginning of the presentation.
105 * If a stream_index >= 0 is used and the protocol does not support
106 * seeking based on component streams, the call will fail with ENOTSUP.
107 * @param timestamp timestamp in AVStream.time_base units
108 * or if there is no stream specified then in AV_TIME_BASE units.
109 * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
110 * and AVSEEK_FLAG_ANY. The protocol may silently ignore
111 * AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
112 * fail with ENOTSUP if used and not supported.
113 * @return >= 0 on success
114 * @see AVInputFormat::read_seek
116 offset_t av_url_read_seek(URLContext *h,
117 int stream_index, int64_t timestamp, int flags);
120 * Passing this as the "whence" parameter to a seek function causes it to
121 * return the filesize without seeking anywhere. Supporting this is optional.
122 * If it is not supported then the seek function will return <0.
124 #define AVSEEK_SIZE 0x10000
126 typedef struct URLProtocol {
128 int (*url_open)(URLContext *h, const char *filename, int flags);
129 int (*url_read)(URLContext *h, unsigned char *buf, int size);
130 int (*url_write)(URLContext *h, unsigned char *buf, int size);
131 offset_t (*url_seek)(URLContext *h, offset_t pos, int whence);
132 int (*url_close)(URLContext *h);
133 struct URLProtocol *next;
134 int (*url_read_pause)(URLContext *h, int pause);
135 offset_t (*url_read_seek)(URLContext *h,
136 int stream_index, int64_t timestamp, int flags);
139 extern URLProtocol *first_protocol;
140 extern URLInterruptCB *url_interrupt_cb;
142 URLProtocol *av_protocol_next(URLProtocol *p);
144 int register_protocol(URLProtocol *protocol);
147 * Bytestream IO Context.
148 * New fields can be added to the end with minor version bumps.
149 * Removal, reordering and changes to existing fields require a major
151 * sizeof(ByteIOContext) must not be used outside libav*.
154 unsigned char *buffer;
156 unsigned char *buf_ptr, *buf_end;
158 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
159 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
160 offset_t (*seek)(void *opaque, offset_t offset, int whence);
161 offset_t pos; /**< position in the file of the current buffer */
162 int must_flush; /**< true if the next seek should flush */
163 int eof_reached; /**< true if eof reached */
164 int write_flag; /**< true if open for writing */
167 unsigned long checksum;
168 unsigned char *checksum_ptr;
169 unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
170 int error; ///< contains the error code or 0 if no error happened
171 int (*read_pause)(void *opaque, int pause);
172 offset_t (*read_seek)(void *opaque,
173 int stream_index, int64_t timestamp, int flags);
176 int init_put_byte(ByteIOContext *s,
177 unsigned char *buffer,
181 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
182 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
183 offset_t (*seek)(void *opaque, offset_t offset, int whence));
184 ByteIOContext *av_alloc_put_byte(
185 unsigned char *buffer,
189 int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
190 int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
191 offset_t (*seek)(void *opaque, offset_t offset, int whence));
193 void put_byte(ByteIOContext *s, int b);
194 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
195 void put_le64(ByteIOContext *s, uint64_t val);
196 void put_be64(ByteIOContext *s, uint64_t val);
197 void put_le32(ByteIOContext *s, unsigned int val);
198 void put_be32(ByteIOContext *s, unsigned int val);
199 void put_le24(ByteIOContext *s, unsigned int val);
200 void put_be24(ByteIOContext *s, unsigned int val);
201 void put_le16(ByteIOContext *s, unsigned int val);
202 void put_be16(ByteIOContext *s, unsigned int val);
203 void put_tag(ByteIOContext *s, const char *tag);
205 void put_strz(ByteIOContext *s, const char *buf);
207 offset_t url_fseek(ByteIOContext *s, offset_t offset, int whence);
208 void url_fskip(ByteIOContext *s, offset_t offset);
209 offset_t url_ftell(ByteIOContext *s);
210 offset_t url_fsize(ByteIOContext *s);
211 int url_feof(ByteIOContext *s);
212 int url_ferror(ByteIOContext *s);
214 int av_url_read_fpause(ByteIOContext *h, int pause);
215 offset_t av_url_read_fseek(ByteIOContext *h,
216 int stream_index, int64_t timestamp, int flags);
219 /** @note return URL_EOF (-1) if EOF */
220 int url_fgetc(ByteIOContext *s);
222 /** @warning currently size is limited */
224 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
226 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
229 /** @note unlike fgets, the EOL character is not returned and a whole
230 line is parsed. return NULL if first char read was EOF */
231 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
233 void put_flush_packet(ByteIOContext *s);
235 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
236 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
238 /** @note return 0 if EOF, so you cannot use it if EOF handling is
240 int get_byte(ByteIOContext *s);
241 unsigned int get_le24(ByteIOContext *s);
242 unsigned int get_le32(ByteIOContext *s);
243 uint64_t get_le64(ByteIOContext *s);
244 unsigned int get_le16(ByteIOContext *s);
246 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
247 unsigned int get_be16(ByteIOContext *s);
248 unsigned int get_be24(ByteIOContext *s);
249 unsigned int get_be32(ByteIOContext *s);
250 uint64_t get_be64(ByteIOContext *s);
252 uint64_t ff_get_v(ByteIOContext *bc);
254 static inline int url_is_streamed(ByteIOContext *s)
256 return s->is_streamed;
259 /** @note when opened as read/write, the buffers are only used for
261 int url_fdopen(ByteIOContext **s, URLContext *h);
263 /** @warning must be called before any I/O */
264 int url_setbufsize(ByteIOContext *s, int buf_size);
265 /** Reset the buffer for reading or writing.
266 * @note Will drop any data currently in the buffer without transmitting it.
267 * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
268 * to set up the buffer for writing. */
269 int url_resetbuf(ByteIOContext *s, int flags);
271 /** @note when opened as read/write, the buffers are only used for
273 int url_fopen(ByteIOContext **s, const char *filename, int flags);
274 int url_fclose(ByteIOContext *s);
275 URLContext *url_fileno(ByteIOContext *s);
278 * Return the maximum packet size associated to packetized buffered file
279 * handle. If the file is not packetized (stream like http or file on
280 * disk), then 0 is returned.
282 * @param s buffered file handle
283 * @return maximum packet size in bytes
285 int url_fget_max_packet_size(ByteIOContext *s);
287 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
289 /** return the written or read size */
290 int url_close_buf(ByteIOContext *s);
293 * Open a write only memory stream.
295 * @param s new IO context
296 * @return zero if no error.
298 int url_open_dyn_buf(ByteIOContext **s);
301 * Open a write only packetized memory stream with a maximum packet
302 * size of 'max_packet_size'. The stream is stored in a memory buffer
303 * with a big endian 4 byte header giving the packet size in bytes.
305 * @param s new IO context
306 * @param max_packet_size maximum packet size (must be > 0)
307 * @return zero if no error.
309 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
312 * Return the written size and a pointer to the buffer. The buffer
313 * must be freed with av_free().
314 * @param s IO context
315 * @param pbuffer pointer to a byte buffer
316 * @return the length of the byte buffer
318 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
320 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, unsigned int len);
321 unsigned long get_checksum(ByteIOContext *s);
322 void init_checksum(ByteIOContext *s, unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len), unsigned long checksum);
325 int udp_set_remote_url(URLContext *h, const char *uri);
326 int udp_get_local_port(URLContext *h);
327 int udp_get_file_handle(URLContext *h);
329 #endif /* FFMPEG_AVIO_H */