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 #if !defined( __LIBVLC__ )
  25   #error You are not libvlc or one of its plugins. You cannot include this file
  26 #endif
  27
  28 #ifndef _VLC_BLOCK_H
  29 #define _VLC_BLOCK_H 1
  30
  31 /****************************************************************************
  32  * block:
  33  ****************************************************************************
  34  * - block_sys_t is opaque and thus block_t->p_sys is PRIVATE
  35  * - i_flags may not always be set (ie could be 0, even for a key frame
  36  *      it depends where you receive the buffer (before/after a packetizer
  37  *      and the demux/packetizer implementations.
  38  * - i_dts/i_pts could be 0, it means no pts
  39  * - i_length: length in microseond of the packet, can be null except in the
  40  *      sout where it is mandatory.
  41  * - i_rate 0 or a valid input rate, look at vlc_input.h
  42  *
  43  * - i_buffer number of valid data pointed by p_buffer
  44  *      you can freely decrease it but never increase it yourself
  45  *      (use block_Realloc)
  46  * - p_buffer: pointer over datas. You should never overwrite it, you can
  47  *   only incremment it to skip datas, in others cases use block_Realloc
  48  *   (don't duplicate yourself in a bigger buffer, block_Realloc is
  49  *   optimised for prehader/postdatas increase)
  50  ****************************************************************************/
  51 typedef struct block_sys_t block_sys_t;
  52
  53 /** The content doesn't follow the last block, or is probably broken */
  54 #define BLOCK_FLAG_DISCONTINUITY 0x0001
  55 /** Intra frame */
  56 #define BLOCK_FLAG_TYPE_I        0x0002
  57 /** Inter frame with backward reference only */
  58 #define BLOCK_FLAG_TYPE_P        0x0004
  59 /** Inter frame with backward and forward reference */
  60 #define BLOCK_FLAG_TYPE_B        0x0008
  61 /** For inter frame when you don't know the real type */
  62 #define BLOCK_FLAG_TYPE_PB       0x0010
  63 /** Warn that this block is a header one */
  64 #define BLOCK_FLAG_HEADER        0x0020
  65 /** This is the last block of the frame */
  66 #define BLOCK_FLAG_END_OF_FRAME  0x0040
  67 /** This is not a key frame for bitrate shaping */
  68 #define BLOCK_FLAG_NO_KEYFRAME   0x0080
  69 /** This block contains a clock reference */
  70 #define BLOCK_FLAG_CLOCK         0x0200
  71 /** This block is scrambled */
  72 #define BLOCK_FLAG_SCRAMBLED     0x0400
  73 /** This block has to be decoded but not be displayed */
  74 #define BLOCK_FLAG_PREROLL       0x0800
  75 /** This block is corrupted and/or there is data loss  */
  76 #define BLOCK_FLAG_CORRUPTED     0x1000
  77
  78 #define BLOCK_FLAG_PRIVATE_MASK  0xffff0000
  79 #define BLOCK_FLAG_PRIVATE_SHIFT 16
  80
  81 typedef void (*block_free_t) (block_t *);
  82
  83 struct block_t
  84 {
  85     block_t     *p_next;
  86     block_t     *p_prev;
  87
  88     uint32_t    i_flags;
  89
  90     mtime_t     i_pts;
  91     mtime_t     i_dts;
  92     mtime_t     i_length;
  93
  94     int         i_samples; /* Used for audio */
  95     int         i_rate;
  96
  97     size_t      i_buffer;
  98     uint8_t     *p_buffer;
  99
 100     /* Rudimentary support for overloading block (de)allocation. */
 101     block_free_t pf_release;
 102 };
 103
 104 /****************************************************************************
 105  * Blocks functions:
 106  ****************************************************************************
 107  * - block_New : create a new block with the requested size ( >= 0 ), return
 108  *      NULL for failure.
 109  * - block_Release : release a block allocated with block_New.
 110  * - block_Realloc : realloc a block,
 111  *      i_pre: how many bytes to insert before body if > 0, else how many
 112  *      bytes of body to skip (the latter can be done without using
 113  *      block_Realloc i_buffer -= -i_pre, p_buffer += -i_pre as i_pre < 0)
 114  *      i_body (>= 0): the final size of the body (decreasing it can directly
 115  *      be done with i_buffer = i_body).
 116  *      with preheader and or body (increase
 117  *      and decrease are supported). Use it as it is optimised.
 118  * - block_Duplicate : create a copy of a block.
 119  ****************************************************************************/
 120 VLC_EXPORT( void,      block_Init,    ( block_t *, void *, size_t ) );
 121 VLC_EXPORT( block_t *, block_Alloc,   ( size_t ) );
 122 VLC_EXPORT( block_t *, block_Realloc, ( block_t *, ssize_t i_pre, size_t i_body ) );
 123
 124 static inline block_t *block_New( void *dummy, size_t size )
 125 {
 126     (void)dummy;
 127     return block_Alloc (size);
 128 }
 129
 130 static inline block_t *block_Duplicate( block_t *p_block )
 131 {
 132     block_t *p_dup = block_New( NULL, p_block->i_buffer );
 133     if( p_dup == NULL )
 134         return NULL;
 135
 136     p_dup->i_dts     = p_block->i_dts;
 137     p_dup->i_pts     = p_block->i_pts;
 138     p_dup->i_flags   = p_block->i_flags;
 139     p_dup->i_length  = p_block->i_length;
 140     p_dup->i_rate    = p_block->i_rate;
 141     p_dup->i_samples = p_block->i_samples;
 142     memcpy( p_dup->p_buffer, p_block->p_buffer, p_block->i_buffer );
 143
 144     return p_dup;
 145 }
 146 static inline void block_Release( block_t *p_block )
 147 {
 148     p_block->pf_release( p_block );
 149 }
 150
 151 /**
 152  * Creates a block from a virtual address memory mapping (mmap).
 153  * This is provided by LibVLC so that mmap blocks can safely be deallocated
 154  * even after the allocating plugin has been unloaded from memory.
 155  *
 156  * @param addr base address of the mapping (as returned by mmap)
 157  * @param length length (bytes) of the mapping (as passed to mmap)
 158  * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
 159  * case, munmap(addr, length) is invoked before returning).
 160  */
 161 VLC_EXPORT( block_t *, block_mmap_Alloc, (void *addr, size_t length) );
 162
 163 /****************************************************************************
 164  * Chains of blocks functions helper
 165  ****************************************************************************
 166  * - block_ChainAppend : append a block the the last block of a chain. Try to
 167  *      avoid using with a lot of data as it's really slow, prefer
 168  *      block_ChainLastAppend
 169  * - block_ChainLastAppend : use a pointer over a pointer to the next blocks,
 170  *      and update it.
 171  * - block_ChainRelease : release a chain of block
 172  * - block_ChainExtract : extract data from a chain, return real bytes counts
 173  * - block_ChainGather : gather a chain, free it and return a block.
 174  ****************************************************************************/
 175 static inline void block_ChainAppend( block_t **pp_list, block_t *p_block )
 176 {
 177     if( *pp_list == NULL )
 178     {
 179         *pp_list = p_block;
 180     }
 181     else
 182     {
 183         block_t *p = *pp_list;
 184
 185         while( p->p_next ) p = p->p_next;
 186         p->p_next = p_block;
 187     }
 188 }
 189
 190 static inline void block_ChainLastAppend( block_t ***ppp_last, block_t *p_block  )
 191 {
 192     block_t *p_last = p_block;
 193
 194     **ppp_last = p_block;
 195
 196     while( p_last->p_next ) p_last = p_last->p_next;
 197     *ppp_last = &p_last->p_next;
 198 }
 199
 200 static inline void block_ChainRelease( block_t *p_block )
 201 {
 202     while( p_block )
 203     {
 204         block_t *p_next = p_block->p_next;
 205         block_Release( p_block );
 206         p_block = p_next;
 207     }
 208 }
 209
 210 static size_t block_ChainExtract( block_t *p_list, void *p_data, size_t i_max )
 211 {
 212     size_t  i_total = 0;
 213     uint8_t *p = (uint8_t*)p_data;
 214
 215     while( p_list && i_max )
 216     {
 217         size_t i_copy = __MIN( i_max, p_list->i_buffer );
 218         memcpy( p, p_list->p_buffer, i_copy );
 219         i_max   -= i_copy;
 220         i_total += i_copy;
 221         p       += i_copy;
 222
 223         p_list = p_list->p_next;
 224     }
 225     return i_total;
 226 }
 227
 228 static inline block_t *block_ChainGather( block_t *p_list )
 229 {
 230     size_t  i_total = 0;
 231     mtime_t i_length = 0;
 232     block_t *b, *g;
 233
 234     if( p_list->p_next == NULL )
 235         return p_list;  /* Already gathered */
 236
 237     for( b = p_list; b != NULL; b = b->p_next )
 238     {
 239         i_total += b->i_buffer;
 240         i_length += b->i_length;
 241     }
 242
 243     g = block_New( NULL, i_total );
 244     block_ChainExtract( p_list, g->p_buffer, g->i_buffer );
 245
 246     g->i_flags = p_list->i_flags;
 247     g->i_pts   = p_list->i_pts;
 248     g->i_dts   = p_list->i_dts;
 249     g->i_length = i_length;
 250
 251     /* free p_list */
 252     block_ChainRelease( p_list );
 253     return g;
 254 }
 255
 256
 257 /****************************************************************************
 258  * Fifos of blocks.
 259  ****************************************************************************
 260  * - block_FifoNew : create and init a new fifo
 261  * - block_FifoRelease : destroy a fifo and free all blocks in it.
 262  * - block_FifoEmpty : free all blocks in a fifo
 263  * - block_FifoPut : put a block
 264  * - block_FifoGet : get a packet from the fifo (and wait if it is empty)
 265  * - block_FifoShow : show the first packet of the fifo (and wait if
 266  *      needed), be carefull, you can use it ONLY if you are sure to be the
 267  *      only one getting data from the fifo.
 268  * - block_FifoCount : how many packets are waiting in the fifo
 269  * - block_FifoSize : how many cumulated bytes are waiting in the fifo
 270  * - block_FifoWake : wake ups a thread with block_FifoGet() = NULL
 271  *   (this is used to wakeup a thread when there is no data to queue)
 272  ****************************************************************************/
 273
 274 #define block_FifoNew( a ) __block_FifoNew( VLC_OBJECT(a) )
 275 VLC_EXPORT( block_fifo_t *, __block_FifoNew,    ( vlc_object_t * ) );
 276 VLC_EXPORT( void,           block_FifoRelease,  ( block_fifo_t * ) );
 277 VLC_EXPORT( void,           block_FifoEmpty,    ( block_fifo_t * ) );
 278 VLC_EXPORT( size_t,         block_FifoPut,      ( block_fifo_t *, block_t * ) );
 279 VLC_EXPORT( void,           block_FifoWake,     ( block_fifo_t * ) );
 280 VLC_EXPORT( block_t *,      block_FifoGet,      ( block_fifo_t * ) );
 281 VLC_EXPORT( block_t *,      block_FifoShow,     ( block_fifo_t * ) );
 282 VLC_EXPORT( size_t,         block_FifoSize,     ( const block_fifo_t *p_fifo ) );
 283 VLC_EXPORT( size_t,         block_FifoCount,    ( const block_fifo_t *p_fifo ) );
 284
 285 #endif /* VLC_BLOCK_H */