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