include/vlc_block.h

   1 /*****************************************************************************
   2  * vlc_block.h: Data blocks management functions
   3  *****************************************************************************
   4  * Copyright (C) 2003 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir@via.ecp.fr>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 #ifndef VLC_BLOCK_H
  25 #define VLC_BLOCK_H 1
  26
  27 /**
  28  * \file
  29  * This file implements functions and structures to handle blocks of data in vlc
  30  *
  31  */
  32
  33 /****************************************************************************
  34  * block:
  35  ****************************************************************************
  36  * - block_sys_t is opaque and thus block_t->p_sys is PRIVATE
  37  * - i_flags may not always be set (ie could be 0, even for a key frame
  38  *      it depends where you receive the buffer (before/after a packetizer
  39  *      and the demux/packetizer implementations.
  40  * - i_dts/i_pts could be 0, it means no pts
  41  * - i_length: length in microseond of the packet, can be null except in the
  42  *      sout where it is mandatory.
  43  * - i_rate 0 or a valid input rate, look at vlc_input.h
  44  *
  45  * - i_buffer number of valid data pointed by p_buffer
  46  *      you can freely decrease it but never increase it yourself
  47  *      (use block_Realloc)
  48  * - p_buffer: pointer over datas. You should never overwrite it, you can
  49  *   only incremment it to skip datas, in others cases use block_Realloc
  50  *   (don't duplicate yourself in a bigger buffer, block_Realloc is
  51  *   optimised for prehader/postdatas increase)
  52  ****************************************************************************/
  53 typedef struct block_sys_t block_sys_t;
  54
  55 /** The content doesn't follow the last block, or is probably broken */
  56 #define BLOCK_FLAG_DISCONTINUITY 0x0001
  57 /** Intra frame */
  58 #define BLOCK_FLAG_TYPE_I        0x0002
  59 /** Inter frame with backward reference only */
  60 #define BLOCK_FLAG_TYPE_P        0x0004
  61 /** Inter frame with backward and forward reference */
  62 #define BLOCK_FLAG_TYPE_B        0x0008
  63 /** For inter frame when you don't know the real type */
  64 #define BLOCK_FLAG_TYPE_PB       0x0010
  65 /** Warn that this block is a header one */
  66 #define BLOCK_FLAG_HEADER        0x0020
  67 /** This is the last block of the frame */
  68 #define BLOCK_FLAG_END_OF_FRAME  0x0040
  69 /** This is not a key frame for bitrate shaping */
  70 #define BLOCK_FLAG_NO_KEYFRAME   0x0080
  71 /** This block contains the last part of a sequence  */
  72 #define BLOCK_FLAG_END_OF_SEQUENCE 0x0100
  73 /** This block contains a clock reference */
  74 #define BLOCK_FLAG_CLOCK         0x0200
  75 /** This block is scrambled */
  76 #define BLOCK_FLAG_SCRAMBLED     0x0400
  77 /** This block has to be decoded but not be displayed */
  78 #define BLOCK_FLAG_PREROLL       0x0800
  79 /** This block is corrupted and/or there is data loss  */
  80 #define BLOCK_FLAG_CORRUPTED     0x1000
  81
  82 #define BLOCK_FLAG_TYPE_MASK \
  83     (BLOCK_FLAG_TYPE_I|BLOCK_FLAG_TYPE_P|BLOCK_FLAG_TYPE_B|BLOCK_FLAG_TYPE_PB)
  84
  85 #define BLOCK_FLAG_PRIVATE_MASK  0xffff0000
  86 #define BLOCK_FLAG_PRIVATE_SHIFT 16
  87
  88 typedef void (*block_free_t) (block_t *);
  89
  90 struct block_t
  91 {
  92     block_t     *p_next;
  93     block_t     *p_prev;
  94
  95     uint32_t    i_flags;
  96
  97     mtime_t     i_pts;
  98     mtime_t     i_dts;
  99     mtime_t     i_length;
 100
 101     int         i_samples; /* Used for audio */
 102     int         i_rate;
 103
 104     size_t      i_buffer;
 105     uint8_t     *p_buffer;
 106
 107     /* Rudimentary support for overloading block (de)allocation. */
 108     block_free_t pf_release;
 109 };
 110
 111 /****************************************************************************
 112  * Blocks functions:
 113  ****************************************************************************
 114  * - block_Alloc : create a new block with the requested size ( >= 0 ), return
 115  *      NULL for failure.
 116  * - block_Release : release a block allocated with block_Alloc.
 117  * - block_Realloc : realloc a block,
 118  *      i_pre: how many bytes to insert before body if > 0, else how many
 119  *      bytes of body to skip (the latter can be done without using
 120  *      block_Realloc i_buffer -= -i_pre, p_buffer += -i_pre as i_pre < 0)
 121  *      i_body (>= 0): the final size of the body (decreasing it can directly
 122  *      be done with i_buffer = i_body).
 123  *      with preheader and or body (increase
 124  *      and decrease are supported). Use it as it is optimised.
 125  * - block_Duplicate : create a copy of a block.
 126  ****************************************************************************/
 127 VLC_EXPORT( void,      block_Init,    ( block_t *, void *, size_t ) );
 128 VLC_EXPORT( block_t *, block_Alloc,   ( size_t ) LIBVLC_USED );
 129 VLC_EXPORT( block_t *, block_Realloc, ( block_t *, ssize_t i_pre, size_t i_body ) LIBVLC_USED );
 130
 131 #define block_New( dummy, size ) block_Alloc(size)
 132
 133 LIBVLC_USED
 134 static inline block_t *block_Duplicate( block_t *p_block )
 135 {
 136     block_t *p_dup = block_Alloc( p_block->i_buffer );
 137     if( p_dup == NULL )
 138         return NULL;
 139
 140     p_dup->i_dts     = p_block->i_dts;
 141     p_dup->i_pts     = p_block->i_pts;
 142     p_dup->i_flags   = p_block->i_flags;
 143     p_dup->i_length  = p_block->i_length;
 144     p_dup->i_rate    = p_block->i_rate;
 145     p_dup->i_samples = p_block->i_samples;
 146     memcpy( p_dup->p_buffer, p_block->p_buffer, p_block->i_buffer );
 147
 148     return p_dup;
 149 }
 150
 151 static inline void block_Release( block_t *p_block )
 152 {
 153     p_block->pf_release( p_block );
 154 }
 155
 156 VLC_EXPORT( block_t *, block_mmap_Alloc, (void *addr, size_t length) LIBVLC_USED );
 157 VLC_EXPORT( block_t *, block_File, (int fd) LIBVLC_USED );
 158
 159 static inline void block_Cleanup (void *block)
 160 {
 161     block_Release ((block_t *)block);
 162 }
 163 #define block_cleanup_push( block ) vlc_cleanup_push (block_Cleanup, block)
 164
 165 /****************************************************************************
 166  * Chains of blocks functions helper
 167  ****************************************************************************
 168  * - block_ChainAppend : append a block to the last block of a chain. Try to
 169  *      avoid using with a lot of data as it's really slow, prefer
 170  *      block_ChainLastAppend
 171  * - block_ChainLastAppend : use a pointer over a pointer to the next blocks,
 172  *      and update it.
 173  * - block_ChainRelease : release a chain of block
 174  * - block_ChainExtract : extract data from a chain, return real bytes counts
 175  * - block_ChainGather : gather a chain, free it and return one block.
 176  ****************************************************************************/
 177 static inline void block_ChainAppend( block_t **pp_list, block_t *p_block )
 178 {
 179     if( *pp_list == NULL )
 180     {
 181         *pp_list = p_block;
 182     }
 183     else
 184     {
 185         block_t *p = *pp_list;
 186
 187         while( p->p_next ) p = p->p_next;
 188         p->p_next = p_block;
 189     }
 190 }
 191
 192 static inline void block_ChainLastAppend( block_t ***ppp_last, block_t *p_block )
 193 {
 194     block_t *p_last = p_block;
 195
 196     **ppp_last = p_block;
 197
 198     while( p_last->p_next ) p_last = p_last->p_next;
 199     *ppp_last = &p_last->p_next;
 200 }
 201
 202 static inline void block_ChainRelease( block_t *p_block )
 203 {
 204     while( p_block )
 205     {
 206         block_t *p_next = p_block->p_next;
 207         block_Release( p_block );
 208         p_block = p_next;
 209     }
 210 }
 211
 212 static size_t block_ChainExtract( block_t *p_list, void *p_data, size_t i_max )
 213 {
 214     size_t  i_total = 0;
 215     uint8_t *p = (uint8_t*)p_data;
 216
 217     while( p_list && i_max )
 218     {
 219         size_t i_copy = __MIN( i_max, p_list->i_buffer );
 220         memcpy( p, p_list->p_buffer, i_copy );
 221         i_max   -= i_copy;
 222         i_total += i_copy;
 223         p       += i_copy;
 224
 225         p_list = p_list->p_next;
 226     }
 227     return i_total;
 228 }
 229
 230 static inline void block_ChainProperties( block_t *p_list, int *pi_count, size_t *pi_size, mtime_t *pi_length )
 231 {
 232     size_t i_size = 0;
 233     mtime_t i_length = 0;
 234     int i_count;
 235
 236     while( p_list )
 237     {
 238         i_size += p_list->i_buffer;
 239         i_length += p_list->i_length;
 240         i_count++;
 241
 242         p_list = p_list->p_next;
 243     }
 244
 245     if( pi_size )
 246         *pi_size = i_size;
 247     if( pi_length )
 248         *pi_length = i_length;
 249     if( pi_count )
 250         *pi_count = i_count;
 251 }
 252
 253 static inline block_t *block_ChainGather( block_t *p_list )
 254 {
 255     size_t  i_total = 0;
 256     mtime_t i_length = 0;
 257     block_t *g;
 258
 259     if( p_list->p_next == NULL )
 260         return p_list;  /* Already gathered */
 261
 262     block_ChainProperties( p_list, NULL, &i_total, &i_length );
 263
 264     g = block_Alloc( i_total );
 265     block_ChainExtract( p_list, g->p_buffer, g->i_buffer );
 266
 267     g->i_flags = p_list->i_flags;
 268     g->i_pts   = p_list->i_pts;
 269     g->i_dts   = p_list->i_dts;
 270     g->i_length = i_length;
 271
 272     /* free p_list */
 273     block_ChainRelease( p_list );
 274     return g;
 275 }
 276
 277 /****************************************************************************
 278  * Fifos of blocks.
 279  ****************************************************************************
 280  * - block_FifoNew : create and init a new fifo
 281  * - block_FifoRelease : destroy a fifo and free all blocks in it.
 282  * - block_FifoEmpty : free all blocks in a fifo
 283  * - block_FifoPut : put a block
 284  * - block_FifoGet : get a packet from the fifo (and wait if it is empty)
 285  * - block_FifoShow : show the first packet of the fifo (and wait if
 286  *      needed), be carefull, you can use it ONLY if you are sure to be the
 287  *      only one getting data from the fifo.
 288  * - block_FifoCount : how many packets are waiting in the fifo
 289  * - block_FifoSize : how many cumulated bytes are waiting in the fifo
 290  * - block_FifoWake : wake ups a thread with block_FifoGet() = NULL
 291  *   (this is used to wakeup a thread when there is no data to queue)
 292  *
 293  * block_FifoGet and block_FifoShow are cancellation points.
 294  ****************************************************************************/
 295
 296 VLC_EXPORT( block_fifo_t *, block_FifoNew,      ( void ) LIBVLC_USED );
 297 VLC_EXPORT( void,           block_FifoRelease,  ( block_fifo_t * ) );
 298 VLC_EXPORT( void,           block_FifoEmpty,    ( block_fifo_t * ) );
 299 VLC_EXPORT( size_t,         block_FifoPut,      ( block_fifo_t *, block_t * ) );
 300 VLC_EXPORT( void,           block_FifoWake,     ( block_fifo_t * ) );
 301 VLC_EXPORT( block_t *,      block_FifoGet,      ( block_fifo_t * ) LIBVLC_USED );
 302 VLC_EXPORT( block_t *,      block_FifoShow,     ( block_fifo_t * ) );
 303 VLC_EXPORT( size_t,         block_FifoSize,     ( const block_fifo_t *p_fifo ) LIBVLC_USED );
 304 VLC_EXPORT( size_t,         block_FifoCount,    ( const block_fifo_t *p_fifo ) LIBVLC_USED );
 305
 306 #endif /* VLC_BLOCK_H */