libavformat/avio.h

   1 /*
   2  * copyright (c) 2001 Fabrice Bellard
   3  *
   4  * This file is part of FFmpeg.
   5  *
   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.
  10  *
  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.
  15  *
  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
  19  */
  20 #ifndef AVFORMAT_AVIO_H
  21 #define AVFORMAT_AVIO_H
  22
  23 /**
  24  * @file libavformat/avio.h
  25  * unbuffered I/O operations
  26  *
  27  * @warning This file has to be considered an internal but installed
  28  * header, so it should not be directly included in your projects.
  29  */
  30
  31 #include <stdint.h>
  32
  33 #include "libavutil/common.h"
  34
  35 /* unbuffered I/O */
  36
  37 /**
  38  * URL Context.
  39  * New fields can be added to the end with minor version bumps.
  40  * Removal, reordering and changes to existing fields require a major
  41  * version bump.
  42  * sizeof(URLContext) must not be used outside libav*.
  43  */
  44 typedef struct URLContext {
  45 #if LIBAVFORMAT_VERSION_MAJOR >= 53
  46     const AVClass *av_class; ///< information for av_log(). Set by url_open().
  47 #endif
  48     struct URLProtocol *prot;
  49     int flags;
  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 */
  52     void *priv_data;
  53     char *filename; /**< specified filename */
  54 } URLContext;
  55
  56 typedef struct URLPollEntry {
  57     URLContext *handle;
  58     int events;
  59     int revents;
  60 } URLPollEntry;
  61
  62 #define URL_RDONLY 0
  63 #define URL_WRONLY 1
  64 #define URL_RDWR   2
  65
  66 typedef int URLInterruptCB(void);
  67
  68 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
  69                        const char *filename, int flags);
  70 int url_open(URLContext **h, const char *filename, int flags);
  71 int url_read(URLContext *h, unsigned char *buf, int size);
  72 int url_read_complete(URLContext *h, unsigned char *buf, int size);
  73 int url_write(URLContext *h, unsigned char *buf, int size);
  74 int64_t url_seek(URLContext *h, int64_t pos, int whence);
  75 int url_close(URLContext *h);
  76 int url_exist(const char *filename);
  77 int64_t url_filesize(URLContext *h);
  78
  79 /**
  80  * Return the file descriptor associated with this URL. For RTP, this
  81  * will return only the RTP file descriptor, not the RTCP file descriptor.
  82  * To get both, use rtp_get_file_handles().
  83  *
  84  * @return the file descriptor associated with this URL, or <0 on error.
  85  */
  86 int url_get_file_handle(URLContext *h);
  87
  88 /**
  89  * Return the maximum packet size associated to packetized file
  90  * handle. If the file is not packetized (stream like HTTP or file on
  91  * disk), then 0 is returned.
  92  *
  93  * @param h file handle
  94  * @return maximum packet size in bytes
  95  */
  96 int url_get_max_packet_size(URLContext *h);
  97 void url_get_filename(URLContext *h, char *buf, int buf_size);
  98
  99 /**
 100  * The callback is called in blocking functions to test regulary if
 101  * asynchronous interruption is needed. AVERROR(EINTR) is returned
 102  * in this case by the interrupted function. 'NULL' means no interrupt
 103  * callback is given.
 104  */
 105 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
 106
 107 /* not implemented */
 108 int url_poll(URLPollEntry *poll_table, int n, int timeout);
 109
 110 /**
 111  * Pause and resume playing - only meaningful if using a network streaming
 112  * protocol (e.g. MMS).
 113  * @param pause 1 for pause, 0 for resume
 114  */
 115 int av_url_read_pause(URLContext *h, int pause);
 116
 117 /**
 118  * Seek to a given timestamp relative to some component stream.
 119  * Only meaningful if using a network streaming protocol (e.g. MMS.).
 120  * @param stream_index The stream index that the timestamp is relative to.
 121  *        If stream_index is (-1) the timestamp should be in AV_TIME_BASE
 122  *        units from the beginning of the presentation.
 123  *        If a stream_index >= 0 is used and the protocol does not support
 124  *        seeking based on component streams, the call will fail with ENOTSUP.
 125  * @param timestamp timestamp in AVStream.time_base units
 126  *        or if there is no stream specified then in AV_TIME_BASE units.
 127  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
 128  *        and AVSEEK_FLAG_ANY. The protocol may silently ignore
 129  *        AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
 130  *        fail with ENOTSUP if used and not supported.
 131  * @return >= 0 on success
 132  * @see AVInputFormat::read_seek
 133  */
 134 int64_t av_url_read_seek(URLContext *h, int stream_index,
 135                          int64_t timestamp, int flags);
 136
 137 /**
 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.
 141  */
 142 #define AVSEEK_SIZE 0x10000
 143
 144 typedef struct URLProtocol {
 145     const char *name;
 146     int (*url_open)(URLContext *h, const char *filename, int flags);
 147     int (*url_read)(URLContext *h, unsigned char *buf, int size);
 148     int (*url_write)(URLContext *h, unsigned char *buf, int size);
 149     int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
 150     int (*url_close)(URLContext *h);
 151     struct URLProtocol *next;
 152     int (*url_read_pause)(URLContext *h, int pause);
 153     int64_t (*url_read_seek)(URLContext *h, int stream_index,
 154                              int64_t timestamp, int flags);
 155     int (*url_get_file_handle)(URLContext *h);
 156 } URLProtocol;
 157
 158 #if LIBAVFORMAT_VERSION_MAJOR < 53
 159 extern URLProtocol *first_protocol;
 160 #endif
 161
 162 extern URLInterruptCB *url_interrupt_cb;
 163
 164 /**
 165  * If protocol is NULL, returns the first registered protocol,
 166  * if protocol is non-NULL, returns the next registered protocol after protocol,
 167  * or NULL if protocol is the last one.
 168  */
 169 URLProtocol *av_protocol_next(URLProtocol *p);
 170
 171 #if LIBAVFORMAT_VERSION_MAJOR < 53
 172 /**
 173  * @deprecated Use av_register_protocol() instead.
 174  */
 175 attribute_deprecated int register_protocol(URLProtocol *protocol);
 176 #endif
 177
 178 int av_register_protocol(URLProtocol *protocol);
 179
 180 /**
 181  * Bytestream IO Context.
 182  * New fields can be added to the end with minor version bumps.
 183  * Removal, reordering and changes to existing fields require a major
 184  * version bump.
 185  * sizeof(ByteIOContext) must not be used outside libav*.
 186  */
 187 typedef struct {
 188     unsigned char *buffer;
 189     int buffer_size;
 190     unsigned char *buf_ptr, *buf_end;
 191     void *opaque;
 192     int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
 193     int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
 194     int64_t (*seek)(void *opaque, int64_t offset, int whence);
 195     int64_t pos; /**< position in the file of the current buffer */
 196     int must_flush; /**< true if the next seek should flush */
 197     int eof_reached; /**< true if eof reached */
 198     int write_flag;  /**< true if open for writing */
 199     int is_streamed;
 200     int max_packet_size;
 201     unsigned long checksum;
 202     unsigned char *checksum_ptr;
 203     unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
 204     int error;         ///< contains the error code or 0 if no error happened
 205     int (*read_pause)(void *opaque, int pause);
 206     int64_t (*read_seek)(void *opaque, int stream_index,
 207                          int64_t timestamp, int flags);
 208 } ByteIOContext;
 209
 210 int init_put_byte(ByteIOContext *s,
 211                   unsigned char *buffer,
 212                   int buffer_size,
 213                   int write_flag,
 214                   void *opaque,
 215                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
 216                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
 217                   int64_t (*seek)(void *opaque, int64_t offset, int whence));
 218 ByteIOContext *av_alloc_put_byte(
 219                   unsigned char *buffer,
 220                   int buffer_size,
 221                   int write_flag,
 222                   void *opaque,
 223                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
 224                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
 225                   int64_t (*seek)(void *opaque, int64_t offset, int whence));
 226
 227 void put_byte(ByteIOContext *s, int b);
 228 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
 229 void put_le64(ByteIOContext *s, uint64_t val);
 230 void put_be64(ByteIOContext *s, uint64_t val);
 231 void put_le32(ByteIOContext *s, unsigned int val);
 232 void put_be32(ByteIOContext *s, unsigned int val);
 233 void put_le24(ByteIOContext *s, unsigned int val);
 234 void put_be24(ByteIOContext *s, unsigned int val);
 235 void put_le16(ByteIOContext *s, unsigned int val);
 236 void put_be16(ByteIOContext *s, unsigned int val);
 237 void put_tag(ByteIOContext *s, const char *tag);
 238
 239 void put_strz(ByteIOContext *s, const char *buf);
 240
 241 /**
 242  * fseek() equivalent for ByteIOContext.
 243  * @return new position or AVERROR.
 244  */
 245 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
 246
 247 /**
 248  * Skip given number of bytes forward.
 249  * @param offset number of bytes
 250  */
 251 void url_fskip(ByteIOContext *s, int64_t offset);
 252
 253 /**
 254  * ftell() equivalent for ByteIOContext.
 255  * @return position or AVERROR.
 256  */
 257 int64_t url_ftell(ByteIOContext *s);
 258
 259 /**
 260  * Gets the filesize.
 261  * @return filesize or AVERROR
 262  */
 263 int64_t url_fsize(ByteIOContext *s);
 264
 265 /**
 266  * feof() equivalent for ByteIOContext.
 267  * @return non zero if and only if end of file
 268  */
 269 int url_feof(ByteIOContext *s);
 270
 271 int url_ferror(ByteIOContext *s);
 272
 273 int av_url_read_fpause(ByteIOContext *h, int pause);
 274 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
 275                           int64_t timestamp, int flags);
 276
 277 #define URL_EOF (-1)
 278 /** @note return URL_EOF (-1) if EOF */
 279 int url_fgetc(ByteIOContext *s);
 280
 281 /** @warning currently size is limited */
 282 #ifdef __GNUC__
 283 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
 284 #else
 285 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
 286 #endif
 287
 288 /** @note unlike fgets, the EOL character is not returned and a whole
 289     line is parsed. return NULL if first char read was EOF */
 290 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
 291
 292 void put_flush_packet(ByteIOContext *s);
 293
 294
 295 /**
 296  * Reads size bytes from ByteIOContext into buf.
 297  * @returns number of bytes read or AVERROR
 298  */
 299 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
 300
 301 /**
 302  * Reads size bytes from ByteIOContext into buf.
 303  * This reads at most 1 packet. If that is not enough fewer bytes will be
 304  * returned.
 305  * @returns number of bytes read or AVERROR
 306  */
 307 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
 308
 309 /** @note return 0 if EOF, so you cannot use it if EOF handling is
 310     necessary */
 311 int get_byte(ByteIOContext *s);
 312 unsigned int get_le24(ByteIOContext *s);
 313 unsigned int get_le32(ByteIOContext *s);
 314 uint64_t get_le64(ByteIOContext *s);
 315 unsigned int get_le16(ByteIOContext *s);
 316
 317 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
 318 unsigned int get_be16(ByteIOContext *s);
 319 unsigned int get_be24(ByteIOContext *s);
 320 unsigned int get_be32(ByteIOContext *s);
 321 uint64_t get_be64(ByteIOContext *s);
 322
 323 uint64_t ff_get_v(ByteIOContext *bc);
 324
 325 static inline int url_is_streamed(ByteIOContext *s)
 326 {
 327     return s->is_streamed;
 328 }
 329
 330 /** @note when opened as read/write, the buffers are only used for
 331     writing */
 332 int url_fdopen(ByteIOContext **s, URLContext *h);
 333
 334 /** @warning must be called before any I/O */
 335 int url_setbufsize(ByteIOContext *s, int buf_size);
 336 /** Reset the buffer for reading or writing.
 337  * @note Will drop any data currently in the buffer without transmitting it.
 338  * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
 339  *        to set up the buffer for writing. */
 340 int url_resetbuf(ByteIOContext *s, int flags);
 341
 342 /** @note when opened as read/write, the buffers are only used for
 343     writing */
 344 int url_fopen(ByteIOContext **s, const char *filename, int flags);
 345 int url_fclose(ByteIOContext *s);
 346 URLContext *url_fileno(ByteIOContext *s);
 347
 348 /**
 349  * Return the maximum packet size associated to packetized buffered file
 350  * handle. If the file is not packetized (stream like http or file on
 351  * disk), then 0 is returned.
 352  *
 353  * @param s buffered file handle
 354  * @return maximum packet size in bytes
 355  */
 356 int url_fget_max_packet_size(ByteIOContext *s);
 357
 358 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
 359
 360 /** return the written or read size */
 361 int url_close_buf(ByteIOContext *s);
 362
 363 /**
 364  * Open a write only memory stream.
 365  *
 366  * @param s new IO context
 367  * @return zero if no error.
 368  */
 369 int url_open_dyn_buf(ByteIOContext **s);
 370
 371 /**
 372  * Open a write only packetized memory stream with a maximum packet
 373  * size of 'max_packet_size'.  The stream is stored in a memory buffer
 374  * with a big endian 4 byte header giving the packet size in bytes.
 375  *
 376  * @param s new IO context
 377  * @param max_packet_size maximum packet size (must be > 0)
 378  * @return zero if no error.
 379  */
 380 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
 381
 382 /**
 383  * Return the written size and a pointer to the buffer. The buffer
 384  *  must be freed with av_free().
 385  * @param s IO context
 386  * @param pbuffer pointer to a byte buffer
 387  * @return the length of the byte buffer
 388  */
 389 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
 390
 391 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
 392                                     unsigned int len);
 393 unsigned long get_checksum(ByteIOContext *s);
 394 void init_checksum(ByteIOContext *s,
 395                    unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
 396                    unsigned long checksum);
 397
 398 /* udp.c */
 399 int udp_set_remote_url(URLContext *h, const char *uri);
 400 int udp_get_local_port(URLContext *h);
 401 #if (LIBAVFORMAT_VERSION_MAJOR <= 52)
 402 int udp_get_file_handle(URLContext *h);
 403 #endif
 404
 405 #endif /* AVFORMAT_AVIO_H */