libavformat/avio.h

   1 /*
   2  * unbuffered io for ffmpeg system
   3  * copyright (c) 2001 Fabrice Bellard
   4  *
   5  * This file is part of FFmpeg.
   6  *
   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.
  11  *
  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.
  16  *
  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
  20  */
  21 #ifndef AVFORMAT_AVIO_H
  22 #define AVFORMAT_AVIO_H
  23
  24 #include <stdint.h>
  25
  26 /* output byte stream handling */
  27
  28 typedef int64_t offset_t;
  29
  30 /* unbuffered I/O */
  31
  32 /**
  33  * URL Context.
  34  * New fields can be added to the end with minor version bumps.
  35  * Removal, reordering and changes to existing fields require a major
  36  * version bump.
  37  * sizeof(URLContext) must not be used outside libav*.
  38  */
  39 struct URLContext {
  40 #if LIBAVFORMAT_VERSION_MAJOR >= 53
  41     const AVClass *av_class; ///< information for av_log(). Set by url_open().
  42 #endif
  43     struct URLProtocol *prot;
  44     int flags;
  45     int is_streamed;  /**< true if streamed (no seek possible), default = false */
  46     int max_packet_size;  /**< if non zero, the stream is packetized with this max packet size */
  47     void *priv_data;
  48     char *filename; /**< specified filename */
  49 };
  50
  51 typedef struct URLContext URLContext;
  52
  53 typedef struct URLPollEntry {
  54     URLContext *handle;
  55     int events;
  56     int revents;
  57 } URLPollEntry;
  58
  59 #define URL_RDONLY 0
  60 #define URL_WRONLY 1
  61 #define URL_RDWR   2
  62
  63 typedef int URLInterruptCB(void);
  64
  65 int url_open_protocol (URLContext **puc, struct URLProtocol *up,
  66                        const char *filename, int flags);
  67 int url_open(URLContext **h, const char *filename, int flags);
  68 int url_read(URLContext *h, unsigned char *buf, int size);
  69 int url_write(URLContext *h, unsigned char *buf, int size);
  70 offset_t url_seek(URLContext *h, offset_t pos, int whence);
  71 int url_close(URLContext *h);
  72 int url_exist(const char *filename);
  73 offset_t url_filesize(URLContext *h);
  74
  75 /**
  76  * Return the maximum packet size associated to packetized file
  77  * handle. If the file is not packetized (stream like HTTP or file on
  78  * disk), then 0 is returned.
  79  *
  80  * @param h file handle
  81  * @return maximum packet size in bytes
  82  */
  83 int url_get_max_packet_size(URLContext *h);
  84 void url_get_filename(URLContext *h, char *buf, int buf_size);
  85
  86 /**
  87  * The callback is called in blocking functions to test regulary if
  88  * asynchronous interruption is needed. AVERROR(EINTR) is returned
  89  * in this case by the interrupted function. 'NULL' means no interrupt
  90  * callback is given.
  91  */
  92 void url_set_interrupt_cb(URLInterruptCB *interrupt_cb);
  93
  94 /* not implemented */
  95 int url_poll(URLPollEntry *poll_table, int n, int timeout);
  96
  97 /**
  98  * Pause and resume playing - only meaningful if using a network streaming
  99  * protocol (e.g. MMS).
 100  * @param pause 1 for pause, 0 for resume
 101  */
 102 int av_url_read_pause(URLContext *h, int pause);
 103
 104 /**
 105  * Seek to a given timestamp relative to some component stream.
 106  * Only meaningful if using a network streaming protocol (e.g. MMS.).
 107  * @param stream_index The stream index that the timestamp is relative to.
 108  *        If stream_index is (-1) the timestamp should be in AV_TIME_BASE
 109  *        units from the beginning of the presentation.
 110  *        If a stream_index >= 0 is used and the protocol does not support
 111  *        seeking based on component streams, the call will fail with ENOTSUP.
 112  * @param timestamp timestamp in AVStream.time_base units
 113  *        or if there is no stream specified then in AV_TIME_BASE units.
 114  * @param flags Optional combination of AVSEEK_FLAG_BACKWARD, AVSEEK_FLAG_BYTE
 115  *        and AVSEEK_FLAG_ANY. The protocol may silently ignore
 116  *        AVSEEK_FLAG_BACKWARD and AVSEEK_FLAG_ANY, but AVSEEK_FLAG_BYTE will
 117  *        fail with ENOTSUP if used and not supported.
 118  * @return >= 0 on success
 119  * @see AVInputFormat::read_seek
 120  */
 121 offset_t av_url_read_seek(URLContext *h,
 122                      int stream_index, int64_t timestamp, int flags);
 123
 124 /**
 125  * Passing this as the "whence" parameter to a seek function causes it to
 126  * return the filesize without seeking anywhere. Supporting this is optional.
 127  * If it is not supported then the seek function will return <0.
 128  */
 129 #define AVSEEK_SIZE 0x10000
 130
 131 typedef struct URLProtocol {
 132     const char *name;
 133     int (*url_open)(URLContext *h, const char *filename, int flags);
 134     int (*url_read)(URLContext *h, unsigned char *buf, int size);
 135     int (*url_write)(URLContext *h, unsigned char *buf, int size);
 136     offset_t (*url_seek)(URLContext *h, offset_t pos, int whence);
 137     int (*url_close)(URLContext *h);
 138     struct URLProtocol *next;
 139     int (*url_read_pause)(URLContext *h, int pause);
 140     offset_t (*url_read_seek)(URLContext *h,
 141                          int stream_index, int64_t timestamp, int flags);
 142 } URLProtocol;
 143
 144 extern URLProtocol *first_protocol;
 145 extern URLInterruptCB *url_interrupt_cb;
 146
 147 URLProtocol *av_protocol_next(URLProtocol *p);
 148
 149 int register_protocol(URLProtocol *protocol);
 150
 151 /**
 152  * Bytestream IO Context.
 153  * New fields can be added to the end with minor version bumps.
 154  * Removal, reordering and changes to existing fields require a major
 155  * version bump.
 156  * sizeof(ByteIOContext) must not be used outside libav*.
 157  */
 158 typedef struct {
 159     unsigned char *buffer;
 160     int buffer_size;
 161     unsigned char *buf_ptr, *buf_end;
 162     void *opaque;
 163     int (*read_packet)(void *opaque, uint8_t *buf, int buf_size);
 164     int (*write_packet)(void *opaque, uint8_t *buf, int buf_size);
 165     offset_t (*seek)(void *opaque, offset_t offset, int whence);
 166     offset_t pos; /**< position in the file of the current buffer */
 167     int must_flush; /**< true if the next seek should flush */
 168     int eof_reached; /**< true if eof reached */
 169     int write_flag;  /**< true if open for writing */
 170     int is_streamed;
 171     int max_packet_size;
 172     unsigned long checksum;
 173     unsigned char *checksum_ptr;
 174     unsigned long (*update_checksum)(unsigned long checksum, const uint8_t *buf, unsigned int size);
 175     int error;         ///< contains the error code or 0 if no error happened
 176     int (*read_pause)(void *opaque, int pause);
 177     offset_t (*read_seek)(void *opaque,
 178                      int stream_index, int64_t timestamp, int flags);
 179 } ByteIOContext;
 180
 181 int init_put_byte(ByteIOContext *s,
 182                   unsigned char *buffer,
 183                   int buffer_size,
 184                   int write_flag,
 185                   void *opaque,
 186                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
 187                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
 188                   offset_t (*seek)(void *opaque, offset_t offset, int whence));
 189 ByteIOContext *av_alloc_put_byte(
 190                   unsigned char *buffer,
 191                   int buffer_size,
 192                   int write_flag,
 193                   void *opaque,
 194                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
 195                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
 196                   offset_t (*seek)(void *opaque, offset_t offset, int whence));
 197
 198 void put_byte(ByteIOContext *s, int b);
 199 void put_buffer(ByteIOContext *s, const unsigned char *buf, int size);
 200 void put_le64(ByteIOContext *s, uint64_t val);
 201 void put_be64(ByteIOContext *s, uint64_t val);
 202 void put_le32(ByteIOContext *s, unsigned int val);
 203 void put_be32(ByteIOContext *s, unsigned int val);
 204 void put_le24(ByteIOContext *s, unsigned int val);
 205 void put_be24(ByteIOContext *s, unsigned int val);
 206 void put_le16(ByteIOContext *s, unsigned int val);
 207 void put_be16(ByteIOContext *s, unsigned int val);
 208 void put_tag(ByteIOContext *s, const char *tag);
 209
 210 void put_strz(ByteIOContext *s, const char *buf);
 211
 212 /**
 213  * fseek() equivalent for ByteIOContext.
 214  * @return new position or AVERROR.
 215  */
 216 offset_t url_fseek(ByteIOContext *s, offset_t offset, int whence);
 217
 218 /**
 219  * Skip given number of bytes forward.
 220  * @param offset number of bytes
 221  */
 222 void url_fskip(ByteIOContext *s, offset_t offset);
 223
 224 /**
 225  * ftell() equivalent for ByteIOContext.
 226  * @return position or AVERROR.
 227  */
 228 offset_t url_ftell(ByteIOContext *s);
 229
 230 /**
 231  * Gets the filesize.
 232  * @return filesize or AVERROR
 233  */
 234 offset_t url_fsize(ByteIOContext *s);
 235
 236 /**
 237  * feof() equivalent for ByteIOContext.
 238  * @return non zero if and only if end of file
 239  */
 240 int url_feof(ByteIOContext *s);
 241
 242 int url_ferror(ByteIOContext *s);
 243
 244 int av_url_read_fpause(ByteIOContext *h, int pause);
 245 offset_t av_url_read_fseek(ByteIOContext *h,
 246                       int stream_index, int64_t timestamp, int flags);
 247
 248 #define URL_EOF (-1)
 249 /** @note return URL_EOF (-1) if EOF */
 250 int url_fgetc(ByteIOContext *s);
 251
 252 /** @warning currently size is limited */
 253 #ifdef __GNUC__
 254 int url_fprintf(ByteIOContext *s, const char *fmt, ...) __attribute__ ((__format__ (__printf__, 2, 3)));
 255 #else
 256 int url_fprintf(ByteIOContext *s, const char *fmt, ...);
 257 #endif
 258
 259 /** @note unlike fgets, the EOL character is not returned and a whole
 260    line is parsed. return NULL if first char read was EOF */
 261 char *url_fgets(ByteIOContext *s, char *buf, int buf_size);
 262
 263 void put_flush_packet(ByteIOContext *s);
 264
 265
 266 /**
 267  * Reads size bytes from ByteIOContext into buf.
 268  * @returns number of bytes read or AVERROR
 269  */
 270 int get_buffer(ByteIOContext *s, unsigned char *buf, int size);
 271
 272 /**
 273  * Reads size bytes from ByteIOContext into buf.
 274  * This reads at most 1 packet. If that is not enough fewer bytes will be
 275  * returned.
 276  * @returns number of bytes read or AVERROR
 277  */
 278 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size);
 279
 280 /** @note return 0 if EOF, so you cannot use it if EOF handling is
 281    necessary */
 282 int get_byte(ByteIOContext *s);
 283 unsigned int get_le24(ByteIOContext *s);
 284 unsigned int get_le32(ByteIOContext *s);
 285 uint64_t get_le64(ByteIOContext *s);
 286 unsigned int get_le16(ByteIOContext *s);
 287
 288 char *get_strz(ByteIOContext *s, char *buf, int maxlen);
 289 unsigned int get_be16(ByteIOContext *s);
 290 unsigned int get_be24(ByteIOContext *s);
 291 unsigned int get_be32(ByteIOContext *s);
 292 uint64_t get_be64(ByteIOContext *s);
 293
 294 uint64_t ff_get_v(ByteIOContext *bc);
 295
 296 static inline int url_is_streamed(ByteIOContext *s)
 297 {
 298     return s->is_streamed;
 299 }
 300
 301 /** @note when opened as read/write, the buffers are only used for
 302    writing */
 303 int url_fdopen(ByteIOContext **s, URLContext *h);
 304
 305 /** @warning must be called before any I/O */
 306 int url_setbufsize(ByteIOContext *s, int buf_size);
 307 /** Reset the buffer for reading or writing.
 308  * @note Will drop any data currently in the buffer without transmitting it.
 309  * @param flags URL_RDONLY to set up the buffer for reading, or URL_WRONLY
 310  *        to set up the buffer for writing. */
 311 int url_resetbuf(ByteIOContext *s, int flags);
 312
 313 /** @note when opened as read/write, the buffers are only used for
 314    writing */
 315 int url_fopen(ByteIOContext **s, const char *filename, int flags);
 316 int url_fclose(ByteIOContext *s);
 317 URLContext *url_fileno(ByteIOContext *s);
 318
 319 /**
 320  * Return the maximum packet size associated to packetized buffered file
 321  * handle. If the file is not packetized (stream like http or file on
 322  * disk), then 0 is returned.
 323  *
 324  * @param s buffered file handle
 325  * @return maximum packet size in bytes
 326  */
 327 int url_fget_max_packet_size(ByteIOContext *s);
 328
 329 int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags);
 330
 331 /** return the written or read size */
 332 int url_close_buf(ByteIOContext *s);
 333
 334 /**
 335  * Open a write only memory stream.
 336  *
 337  * @param s new IO context
 338  * @return zero if no error.
 339  */
 340 int url_open_dyn_buf(ByteIOContext **s);
 341
 342 /**
 343  * Open a write only packetized memory stream with a maximum packet
 344  * size of 'max_packet_size'.  The stream is stored in a memory buffer
 345  * with a big endian 4 byte header giving the packet size in bytes.
 346  *
 347  * @param s new IO context
 348  * @param max_packet_size maximum packet size (must be > 0)
 349  * @return zero if no error.
 350  */
 351 int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size);
 352
 353 /**
 354  * Return the written size and a pointer to the buffer. The buffer
 355  *  must be freed with av_free().
 356  * @param s IO context
 357  * @param pbuffer pointer to a byte buffer
 358  * @return the length of the byte buffer
 359  */
 360 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer);
 361
 362 unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, unsigned int len);
 363 unsigned long get_checksum(ByteIOContext *s);
 364 void init_checksum(ByteIOContext *s, unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len), unsigned long checksum);
 365
 366 /* udp.c */
 367 int udp_set_remote_url(URLContext *h, const char *uri);
 368 int udp_get_local_port(URLContext *h);
 369 int udp_get_file_handle(URLContext *h);
 370
 371 #endif /* AVFORMAT_AVIO_H */