include/vlc_block.h

   1 /*****************************************************************************
   2  * vlc_block.h: Data blocks management functions
   3  *****************************************************************************
   4  * Copyright (C) 2003 VLC authors and VideoLAN
   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 it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * 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 #include <sys/types.h>  /* for ssize_t */
  34
  35 /****************************************************************************
  36  * block:
  37  ****************************************************************************
  38  * - i_flags may not always be set (ie could be 0, even for a key frame
  39  *      it depends where you receive the buffer (before/after a packetizer
  40  *      and the demux/packetizer implementations.
  41  * - i_dts/i_pts could be VLC_TS_INVALID, it means no pts/dts
  42  * - i_length: length in microseond of the packet, can be null except in the
  43  *      sout where it is mandatory.
  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 preheader/postdatas increase)
  52  ****************************************************************************/
  53
  54 /** The content doesn't follow the last block, or is probably broken */
  55 #define BLOCK_FLAG_DISCONTINUITY 0x0001
  56 /** Intra frame */
  57 #define BLOCK_FLAG_TYPE_I        0x0002
  58 /** Inter frame with backward reference only */
  59 #define BLOCK_FLAG_TYPE_P        0x0004
  60 /** Inter frame with backward and forward reference */
  61 #define BLOCK_FLAG_TYPE_B        0x0008
  62 /** For inter frame when you don't know the real type */
  63 #define BLOCK_FLAG_TYPE_PB       0x0010
  64 /** Warn that this block is a header one */
  65 #define BLOCK_FLAG_HEADER        0x0020
  66 /** This is the last block of the frame */
  67 #define BLOCK_FLAG_END_OF_FRAME  0x0040
  68 /** This is not a key frame for bitrate shaping */
  69 #define BLOCK_FLAG_NO_KEYFRAME   0x0080
  70 /** This block contains the last part of a sequence  */
  71 #define BLOCK_FLAG_END_OF_SEQUENCE 0x0100
  72 /** This block contains a clock reference */
  73 #define BLOCK_FLAG_CLOCK         0x0200
  74 /** This block is scrambled */
  75 #define BLOCK_FLAG_SCRAMBLED     0x0400
  76 /** This block has to be decoded but not be displayed */
  77 #define BLOCK_FLAG_PREROLL       0x0800
  78 /** This block is corrupted and/or there is data loss  */
  79 #define BLOCK_FLAG_CORRUPTED     0x1000
  80 /** This block contains an interlaced picture with top field first */
  81 #define BLOCK_FLAG_TOP_FIELD_FIRST 0x2000
  82 /** This block contains an interlaced picture with bottom field first */
  83 #define BLOCK_FLAG_BOTTOM_FIELD_FIRST 0x4000
  84
  85 /** This block contains an interlaced picture */
  86 #define BLOCK_FLAG_INTERLACED_MASK \
  87     (BLOCK_FLAG_TOP_FIELD_FIRST|BLOCK_FLAG_BOTTOM_FIELD_FIRST)
  88
  89 #define BLOCK_FLAG_TYPE_MASK \
  90     (BLOCK_FLAG_TYPE_I|BLOCK_FLAG_TYPE_P|BLOCK_FLAG_TYPE_B|BLOCK_FLAG_TYPE_PB)
  91
  92 /* These are for input core private usage only */
  93 #define BLOCK_FLAG_CORE_PRIVATE_MASK  0x00ff0000
  94 #define BLOCK_FLAG_CORE_PRIVATE_SHIFT 16
  95
  96 /* These are for module private usage only */
  97 #define BLOCK_FLAG_PRIVATE_MASK  0xff000000
  98 #define BLOCK_FLAG_PRIVATE_SHIFT 24
  99
 100 typedef void (*block_free_t) (block_t *);
 101
 102 struct block_t
 103 {
 104     block_t    *p_next;
 105
 106     uint8_t    *p_buffer; /**< Payload start */
 107     size_t      i_buffer; /**< Payload length */
 108     uint8_t    *p_start; /**< Buffer start */
 109     size_t      i_size; /**< Buffer total size */
 110
 111     uint32_t    i_flags;
 112     unsigned    i_nb_samples; /* Used for audio */
 113
 114     mtime_t     i_pts;
 115     mtime_t     i_dts;
 116     mtime_t     i_length;
 117
 118     /* Rudimentary support for overloading block (de)allocation. */
 119     block_free_t pf_release;
 120 };
 121
 122 /****************************************************************************
 123  * Blocks functions:
 124  ****************************************************************************
 125  * - block_Alloc : create a new block with the requested size ( >= 0 ), return
 126  *      NULL for failure.
 127  * - block_Release : release a block allocated with block_Alloc.
 128  * - block_Realloc : realloc a block,
 129  *      i_pre: how many bytes to insert before body if > 0, else how many
 130  *      bytes of body to skip (the latter can be done without using
 131  *      block_Realloc i_buffer -= -i_pre, p_buffer += -i_pre as i_pre < 0)
 132  *      i_body (>= 0): the final size of the body (decreasing it can directly
 133  *      be done with i_buffer = i_body).
 134  *      with preheader and or body (increase
 135  *      and decrease are supported). Use it as it is optimised.
 136  * - block_Duplicate : create a copy of a block.
 137  ****************************************************************************/
 138 VLC_API void block_Init( block_t *, void *, size_t );
 139 VLC_API block_t *block_Alloc( size_t ) VLC_USED VLC_MALLOC;
 140 VLC_API block_t *block_Realloc( block_t *, ssize_t i_pre, size_t i_body ) VLC_USED;
 141
 142 static inline void block_CopyProperties( block_t *dst, block_t *src )
 143 {
 144     dst->i_flags   = src->i_flags;
 145     dst->i_nb_samples = src->i_nb_samples;
 146     dst->i_dts     = src->i_dts;
 147     dst->i_pts     = src->i_pts;
 148     dst->i_length  = src->i_length;
 149 }
 150
 151 VLC_USED
 152 static inline block_t *block_Duplicate( block_t *p_block )
 153 {
 154     block_t *p_dup = block_Alloc( p_block->i_buffer );
 155     if( p_dup == NULL )
 156         return NULL;
 157
 158     block_CopyProperties( p_dup, p_block );
 159     memcpy( p_dup->p_buffer, p_block->p_buffer, p_block->i_buffer );
 160
 161     return p_dup;
 162 }
 163
 164 static inline void block_Release( block_t *p_block )
 165 {
 166     p_block->pf_release( p_block );
 167 }
 168
 169 VLC_API block_t *block_heap_Alloc(void *, size_t) VLC_USED VLC_MALLOC;
 170 VLC_API block_t *block_mmap_Alloc(void *addr, size_t length) VLC_USED VLC_MALLOC;
 171 VLC_API block_t * block_shm_Alloc(void *addr, size_t length) VLC_USED VLC_MALLOC;
 172 VLC_API block_t *block_File(int fd) VLC_USED VLC_MALLOC;
 173 VLC_API block_t *block_FilePath(const char *) VLC_USED VLC_MALLOC;
 174
 175 static inline void block_Cleanup (void *block)
 176 {
 177     block_Release ((block_t *)block);
 178 }
 179 #define block_cleanup_push( block ) vlc_cleanup_push (block_Cleanup, block)
 180
 181 /****************************************************************************
 182  * Chains of blocks functions helper
 183  ****************************************************************************
 184  * - block_ChainAppend : append a block to the last block of a chain. Try to
 185  *      avoid using with a lot of data as it's really slow, prefer
 186  *      block_ChainLastAppend, p_block can be NULL
 187  * - block_ChainLastAppend : use a pointer over a pointer to the next blocks,
 188  *      and update it.
 189  * - block_ChainRelease : release a chain of block
 190  * - block_ChainExtract : extract data from a chain, return real bytes counts
 191  * - block_ChainGather : gather a chain, free it and return one block.
 192  ****************************************************************************/
 193 static inline void block_ChainAppend( block_t **pp_list, block_t *p_block )
 194 {
 195     if( *pp_list == NULL )
 196     {
 197         *pp_list = p_block;
 198     }
 199     else
 200     {
 201         block_t *p = *pp_list;
 202
 203         while( p->p_next ) p = p->p_next;
 204         p->p_next = p_block;
 205     }
 206 }
 207
 208 static inline void block_ChainLastAppend( block_t ***ppp_last, block_t *p_block )
 209 {
 210     block_t *p_last = p_block;
 211
 212     **ppp_last = p_block;
 213
 214     while( p_last->p_next ) p_last = p_last->p_next;
 215     *ppp_last = &p_last->p_next;
 216 }
 217
 218 static inline void block_ChainRelease( block_t *p_block )
 219 {
 220     while( p_block )
 221     {
 222         block_t *p_next = p_block->p_next;
 223         block_Release( p_block );
 224         p_block = p_next;
 225     }
 226 }
 227
 228 static size_t block_ChainExtract( block_t *p_list, void *p_data, size_t i_max )
 229 {
 230     size_t  i_total = 0;
 231     uint8_t *p = (uint8_t*)p_data;
 232
 233     while( p_list && i_max )
 234     {
 235         size_t i_copy = __MIN( i_max, p_list->i_buffer );
 236         memcpy( p, p_list->p_buffer, i_copy );
 237         i_max   -= i_copy;
 238         i_total += i_copy;
 239         p       += i_copy;
 240
 241         p_list = p_list->p_next;
 242     }
 243     return i_total;
 244 }
 245
 246 static inline void block_ChainProperties( block_t *p_list, int *pi_count, size_t *pi_size, mtime_t *pi_length )
 247 {
 248     size_t i_size = 0;
 249     mtime_t i_length = 0;
 250     int i_count = 0;
 251
 252     while( p_list )
 253     {
 254         i_size += p_list->i_buffer;
 255         i_length += p_list->i_length;
 256         i_count++;
 257
 258         p_list = p_list->p_next;
 259     }
 260
 261     if( pi_size )
 262         *pi_size = i_size;
 263     if( pi_length )
 264         *pi_length = i_length;
 265     if( pi_count )
 266         *pi_count = i_count;
 267 }
 268
 269 static inline block_t *block_ChainGather( block_t *p_list )
 270 {
 271     size_t  i_total = 0;
 272     mtime_t i_length = 0;
 273     block_t *g;
 274
 275     if( p_list->p_next == NULL )
 276         return p_list;  /* Already gathered */
 277
 278     block_ChainProperties( p_list, NULL, &i_total, &i_length );
 279
 280     g = block_Alloc( i_total );
 281     block_ChainExtract( p_list, g->p_buffer, g->i_buffer );
 282
 283     g->i_flags = p_list->i_flags;
 284     g->i_pts   = p_list->i_pts;
 285     g->i_dts   = p_list->i_dts;
 286     g->i_length = i_length;
 287
 288     /* free p_list */
 289     block_ChainRelease( p_list );
 290     return g;
 291 }
 292
 293 /****************************************************************************
 294  * Fifos of blocks.
 295  ****************************************************************************
 296  * - block_FifoNew : create and init a new fifo
 297  * - block_FifoRelease : destroy a fifo and free all blocks in it.
 298  * - block_FifoPace : wait for a fifo to drain to a specified number of packets or total data size
 299  * - block_FifoEmpty : free all blocks in a fifo
 300  * - block_FifoPut : put a block
 301  * - block_FifoGet : get a packet from the fifo (and wait if it is empty)
 302  * - block_FifoShow : show the first packet of the fifo (and wait if
 303  *      needed), be carefull, you can use it ONLY if you are sure to be the
 304  *      only one getting data from the fifo.
 305  * - block_FifoCount : how many packets are waiting in the fifo
 306  *
 307  * block_FifoGet and block_FifoShow are cancellation points.
 308  ****************************************************************************/
 309
 310 VLC_API block_fifo_t *block_FifoNew( void ) VLC_USED VLC_MALLOC;
 311 VLC_API void block_FifoRelease( block_fifo_t * );
 312 VLC_API void block_FifoPace( block_fifo_t *fifo, size_t max_depth, size_t max_size );
 313 VLC_API void block_FifoEmpty( block_fifo_t * );
 314 VLC_API size_t block_FifoPut( block_fifo_t *, block_t * );
 315 void block_FifoWake( block_fifo_t * );
 316 VLC_API block_t * block_FifoGet( block_fifo_t * ) VLC_USED;
 317 VLC_API block_t * block_FifoShow( block_fifo_t * );
 318 size_t block_FifoSize( const block_fifo_t *p_fifo ) VLC_USED;
 319 VLC_API size_t block_FifoCount( const block_fifo_t *p_fifo ) VLC_USED;
 320
 321 #endif /* VLC_BLOCK_H */