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 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 };
  55
  56 typedef struct URLContext URLContext;
  57
  58 typedef struct URLPollEntry {
  59     URLContext *handle;
  60     int events;
  61     int revents;
  62 } URLPollEntry;
  63
  64 #define URL_RDONLY 0
  65 #define URL_WRONLY 1
  66 #define URL_RDWR   2
  67
  68 typedef int URLInterruptCB(void);
  69
  70 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
  71                        const char *filename, int flags);
  72 int url_open(URLContext **h, const char *filename, int flags);
  73 int url_read(URLContext *h, unsigned char *buf, int size);
  74 int url_write(URLContext *h, unsigned char *buf, int size);
  75 int64_t url_seek(URLContext *h, int64_t pos, int whence);
  76 int url_close(URLContext *h);
  77 int url_exist(const char *filename);
  78 int64_t url_filesize(URLContext *h);
  79
  80 /**
  81  * Return the file descriptor associated with this URL. For RTP, this
  82  * will return only the RTP file descriptor, not the RTCP file descriptor.
  83  * To get both, use rtp_get_file_handles().
  84  *
  85  * @return the file descriptor associated with this URL, or <0 on error.
  86  */
  87 int url_get_file_handle(URLContext *h);
  88
  89 /**
  90  * Return the maximum packet size associated to packetized file
  91  * handle. If the file is not packetized (stream like HTTP or file on
  92  * disk), then 0 is returned.
  93  *
  94  * @param h file handle
  95  * @return maximum packet size in bytes
  96  */
  97 int url_get_max_packet_size(URLContext *h);
  98 void url_get_filename(URLContext *h, char *buf, int buf_size);
  99
 100 /**
 101  * The callback is called in blocking functions to test regulary if
 102  * asynchronous interruption is needed. AVERROR(EINTR) is returned
 103  * in this case by the interrupted function. 'NULL' means no interrupt
 104  * callback is given.
 105  */
 106 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
 107
 108 /* not implemented */
 109 int url_poll(URLPollEntry *poll_table, int n, int timeout);
 110
 111 /**
 112  * Pause and resume playing - only meaningful if using a network streaming
 113  * protocol (e.g. MMS).
 114  * @param pause 1 for pause, 0 for resume
 115  */
 116 int av_url_read_pause(URLContext *h, int pause);
 117
 118 /**
 119  * Seek to a given timestamp relative to some component stream.
 120  * Only meaningful if using a network streaming protocol (e.g. MMS.).
 121  * @param stream_index The stream index that the timestamp is relative to.
 122  *        If stream_index is (-1) the timestamp should be in AV_TIME_BASE
 123  *        units from the beginning of the presentation.
 124  *        If a stream_index >= 0 is used and the protocol does not support
 125  *        seeking based on component streams, the call will fail with ENOTSUP.
 126  * @param timestamp timestamp in AVStream.time_base units
 127  *        or if there is no stream specified then in AV_TIME_BASE units.
 128  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
 129  *        and AVSEEK_FLAG_ANY. The protocol may silently ignore
 130  *        AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
 131  *        fail with ENOTSUP if used and not supported.
 132  * @return >= 0 on success
 133  * @see AVInputFormat::read_seek
 134  */
 135 int64_t av_url_read_seek(URLContext *h, int stream_index,
 136                          int64_t timestamp, int flags);
 137
 138 /**
 139  * Passing this as the "whence" parameter to a seek function causes it to
 140  * return the filesize without seeking anywhere. Supporting this is optional.
 141  * If it is not supported then the seek function will return <0.
 142  */
 143 #define AVSEEK_SIZE 0x10000
 144
 145 typedef struct URLProtocol {
 146     const char *name;
 147     int (*url_open)(URLContext *h, const char *filename, int flags);
 148     int (*url_read)(URLContext *h, unsigned char *buf, int size);
 149     int (*url_write)(URLContext *h, unsigned char *buf, int size);
 150     int64_t (*url_seek)(URLContext *h, int64_t pos, int whence);
 151     int (*url_close)(URLContext *h);
 152     struct URLProtocol *next;
 153     int (*url_read_pause)(URLContext *h, int pause);
 154     int64_t (*url_read_seek)(URLContext *h, int stream_index,
 155                              int64_t timestamp, int flags);
 156     int (*url_get_file_handle)(URLContext *h);
 157 } URLProtocol;
 158
 159 #if LIBAVFORMAT_VERSION_MAJOR < 53
 160 extern URLProtocol *first_protocol;
 161 #endif
 162
 163 extern URLInterruptCB *url_interrupt_cb;
 164
 165 /**
 166  * If protocol is NULL, returns the first registered protocol,
 167  * if protocol is non-NULL, returns the next registered protocol after protocol,
 168  * or NULL if protocol is the last one.
 169  */
 170 URLProtocol *av_protocol_next(URLProtocol *p);
 171
 172 #if LIBAVFORMAT_VERSION_MAJOR < 53
 173 /**
 174  * @deprecated Use av_register_protocol() instead.
 175  */
 176 attribute_deprecated int register_protocol(URLProtocol *protocol);
 177 #endif
 178
 179 int av_register_protocol(URLProtocol *protocol);
 180
 181 /**
 182  * Bytestream IO Context.
 183  * New fields can be added to the end with minor version bumps.
 184  * Removal, reordering and changes to existing fields require a major
 185  * version bump.
 186  * sizeof(ByteIOContext) must not be used outside libav*.
 187  */
 188 typedef struct {
 189     unsigned char *buffer;
 190     int buffer_size;
 191     unsigned char *buf_ptr, *buf_end;
 192     void *opaque;
 193     int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
 194     int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
 195     int64_t (*seek)(void *opaque, int64_t offset, int whence);
 196     int64_t pos; /**< position in the file of the current buffer */
 197     int must_flush; /**< true if the next seek should flush */
 198     int eof_reached; /**< true if eof reached */
 199     int write_flag;  /**< true if open for writing */
 200     int is_streamed;
 201     int max_packet_size;
 202     unsigned long checksum;
 203     unsigned char *checksum_ptr;
 204     unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
 205     int error;         ///< contains the error code or 0 if no error happened
 206     int (*read_pause)(void *opaque, int pause);
 207     int64_t (*read_seek)(void *opaque, int stream_index,
 208                          int64_t timestamp, int flags);
 209 } ByteIOContext;
 210
 211 int init_put_byte(ByteIOContext *s,
 212                   unsigned char *buffer,
 213                   int buffer_size,
 214                   int write_flag,
 215                   void *opaque,
 216                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
 217                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
 218                   int64_t (*seek)(void *opaque, int64_t offset, int whence));
 219 ByteIOContext *av_alloc_put_byte(
 220                   unsigned char *buffer,
 221                   int buffer_size,
 222                   int write_flag,
 223                   void *opaque,
 224                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
 225                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
 226                   int64_t (*seek)(void *opaque, int64_t offset, int whence));
 227
 228 void put_byte(ByteIOContext *s, int b);
 229 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
 230 void put_le64(ByteIOContext *s, uint64_t val);
 231 void put_be64(ByteIOContext *s, uint64_t val);
 232 void put_le32(ByteIOContext *s, unsigned int val);
 233 void put_be32(ByteIOContext *s, unsigned int val);
 234 void put_le24(ByteIOContext *s, unsigned int val);
 235 void put_be24(ByteIOContext *s, unsigned int val);
 236 void put_le16(ByteIOContext *s, unsigned int val);
 237 void put_be16(ByteIOContext *s, unsigned int val);
 238 void put_tag(ByteIOContext *s, const char *tag);
 239
 240 void put_strz(ByteIOContext *s, const char *buf);
 241
 242 /**
 243  * fseek() equivalent for ByteIOContext.
 244  * @return new position or AVERROR.
 245  */
 246 int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence);
 247
 248 /**
 249  * Skip given number of bytes forward.
 250  * @param offset number of bytes
 251  */
 252 void url_fskip(ByteIOContext *s, int64_t offset);
 253
 254 /**
 255  * ftell() equivalent for ByteIOContext.
 256  * @return position or AVERROR.
 257  */
 258 int64_t url_ftell(ByteIOContext *s);
 259
 260 /**
 261  * Gets the filesize.
 262  * @return filesize or AVERROR
 263  */
 264 int64_t url_fsize(ByteIOContext *s);
 265
 266 /**
 267  * feof() equivalent for ByteIOContext.
 268  * @return non zero if and only if end of file
 269  */
 270 int url_feof(ByteIOContext *s);
 271
 272 int url_ferror(ByteIOContext *s);
 273
 274 int av_url_read_fpause(ByteIOContext *h, int pause);
 275 int64_t av_url_read_fseek(ByteIOContext *h, int stream_index,
 276                           int64_t timestamp, int flags);
 277
 278 #define URL_EOF (-1)
 279 /** @note return URL_EOF (-1) if EOF */
 280 int url_fgetc(ByteIOContext *s);
 281
 282 /** @warning currently size is limited */
 283 #ifdef __GNUC__
 284 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
 285 #else
 286 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
 287 #endif
 288
 289 /** @note unlike fgets, the EOL character is not returned and a whole
 290     line is parsed. return NULL if first char read was EOF */
 291 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
 292
 293 void put_flush_packet(ByteIOContext *s);
 294
 295
 296 /**
 297  * Reads size bytes from ByteIOContext into buf.
 298  * @returns number of bytes read or AVERROR
 299  */
 300 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
 301
 302 /**
 303  * Reads size bytes from ByteIOContext into buf.
 304  * This reads at most 1 packet. If that is not enough fewer bytes will be
 305  * returned.
 306  * @returns number of bytes read or AVERROR
 307  */
 308 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
 309
 310 /** @note return 0 if EOF, so you cannot use it if EOF handling is
 311     necessary */
 312 int get_byte(ByteIOContext *s);
 313 unsigned int get_le24(ByteIOContext *s);
 314 unsigned int get_le32(ByteIOContext *s);
 315 uint64_t get_le64(ByteIOContext *s);
 316 unsigned int get_le16(ByteIOContext *s);
 317
 318 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
 319 unsigned int get_be16(ByteIOContext *s);
 320 unsigned int get_be24(ByteIOContext *s);
 321 unsigned int get_be32(ByteIOContext *s);
 322 uint64_t get_be64(ByteIOContext *s);
 323
 324 uint64_t ff_get_v(ByteIOContext *bc);
 325
 326 static inline int url_is_streamed(ByteIOContext *s)
 327 {
 328     return s->is_streamed;
 329 }
 330
 331 /** @note when opened as read/write, the buffers are only used for
 332     writing */
 333 int url_fdopen(ByteIOContext **s, URLContext *h);
 334
 335 /** @warning must be called before any I/O */
 336 int url_setbufsize(ByteIOContext *s, int buf_size);
 337 /** Reset the buffer for reading or writing.
 338  * @note Will drop any data currently in the buffer without transmitting it.
 339  * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
 340  *        to set up the buffer for writing. */
 341 int url_resetbuf(ByteIOContext *s, int flags);
 342
 343 /** @note when opened as read/write, the buffers are only used for
 344     writing */
 345 int url_fopen(ByteIOContext **s, const char *filename, int flags);
 346 int url_fclose(ByteIOContext *s);
 347 URLContext *url_fileno(ByteIOContext *s);
 348
 349 /**
 350  * Return the maximum packet size associated to packetized buffered file
 351  * handle. If the file is not packetized (stream like http or file on
 352  * disk), then 0 is returned.
 353  *
 354  * @param s buffered file handle
 355  * @return maximum packet size in bytes
 356  */
 357 int url_fget_max_packet_size(ByteIOContext *s);
 358
 359 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
 360
 361 /** return the written or read size */
 362 int url_close_buf(ByteIOContext *s);
 363
 364 /**
 365  * Open a write only memory stream.
 366  *
 367  * @param s new IO context
 368  * @return zero if no error.
 369  */
 370 int url_open_dyn_buf(ByteIOContext **s);
 371
 372 /**
 373  * Open a write only packetized memory stream with a maximum packet
 374  * size of 'max_packet_size'.  The stream is stored in a memory buffer
 375  * with a big endian 4 byte header giving the packet size in bytes.
 376  *
 377  * @param s new IO context
 378  * @param max_packet_size maximum packet size (must be > 0)
 379  * @return zero if no error.
 380  */
 381 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
 382
 383 /**
 384  * Return the written size and a pointer to the buffer. The buffer
 385  *  must be freed with av_free().
 386  * @param s IO context
 387  * @param pbuffer pointer to a byte buffer
 388  * @return the length of the byte buffer
 389  */
 390 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
 391
 392 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
 393                                     unsigned int len);
 394 unsigned long get_checksum(ByteIOContext *s);
 395 void init_checksum(ByteIOContext *s,
 396                    unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
 397                    unsigned long checksum);
 398
 399 /* udp.c */
 400 int udp_set_remote_url(URLContext *h, const char *uri);
 401 int udp_get_local_port(URLContext *h);
 402 #if (LIBAVFORMAT_VERSION_MAJOR <= 52)
 403 int udp_get_file_handle(URLContext *h);
 404 #endif
 405
 406 #endif /* AVFORMAT_AVIO_H */