git.sesse.net Git - vlc/blob - src/misc/block.c

   1 /*****************************************************************************
   2  * block.c: Data blocks management functions
   3  *****************************************************************************
   4  * Copyright (C) 2003-2004 VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Laurent Aimar <fenrir@videolan.org>
   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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27 #include <stdlib.h>
  28
  29 #include <vlc/vlc.h>
  30 #include "vlc_block.h"
  31
  32 /*****************************************************************************
  33  * Block functions.
  34  *****************************************************************************/
  35 /* private */
  36 struct block_sys_t
  37 {
  38     uint8_t     *p_allocated_buffer;
  39     int         i_allocated_buffer;
  40 };
  41
  42 #define BLOCK_PADDING_SIZE 32
  43 static void BlockRelease( block_t * );
  44
  45 block_t *__block_New( vlc_object_t *p_obj, int i_size )
  46 {
  47     /* We do only one malloc
  48      * TODO bench if doing 2 malloc but keeping a pool of buffer is better
  49      * 16 -> align on 16
  50      * 2*BLOCK_PADDING_SIZE -> pre + post padding
  51      */
  52     const int    i_alloc = i_size + 2*BLOCK_PADDING_SIZE + 16;
  53     block_t     *p_block = malloc( sizeof( block_t ) + sizeof( block_sys_t ) + i_alloc );
  54     block_sys_t *p_sys;
  55
  56     if( p_block == NULL )
  57         return NULL;
  58
  59     /* Fill opaque data */
  60     p_sys = (block_sys_t*)( (uint8_t*)p_block + sizeof( block_t ) );
  61     p_sys->i_allocated_buffer = i_alloc;
  62     p_sys->p_allocated_buffer = (uint8_t*)p_block + sizeof( block_t ) + sizeof( block_sys_t );
  63
  64     /* Fill all fields */
  65     p_block->p_next         = NULL;
  66     p_block->i_flags        = 0;
  67     p_block->i_pts          = 0;
  68     p_block->i_dts          = 0;
  69     p_block->i_length       = 0;
  70     p_block->i_rate         = 0;
  71     p_block->i_buffer       = i_size;
  72     p_block->p_buffer       = &p_sys->p_allocated_buffer[32+15-((long)p_sys->p_allocated_buffer % 16 )];
  73     p_block->pf_release     = BlockRelease;
  74     p_block->p_manager      = VLC_OBJECT( p_obj->p_vlc );   /* Is ok, as no comunication between p_vlc */
  75     p_block->p_sys          = p_sys;
  76
  77     return p_block;
  78 }
  79
  80 block_t *block_Realloc( block_t *p_block, int i_prebody, int i_body )
  81 {
  82     int i_buffer_size;
  83
  84     if( p_block->pf_release != BlockRelease )
  85     {
  86         /* Special case when pf_release if overloaded
  87          * TODO if used one day, them implement it in a smarter way */
  88         block_t *p_dup = block_Duplicate( p_block );
  89         block_Release( p_block );
  90
  91         p_block = p_dup;
  92     }
  93
  94     i_buffer_size = i_prebody + i_body;
  95
  96     if( i_body < 0 || i_buffer_size <= 0 ) return NULL;
  97
  98     if( i_prebody < ( p_block->p_buffer - p_block->p_sys->p_allocated_buffer +
  99                       p_block->p_sys->i_allocated_buffer ) ||
 100         p_block->p_buffer - i_prebody > p_block->p_sys->p_allocated_buffer )
 101     {
 102         p_block->p_buffer -= i_prebody;
 103         p_block->i_buffer += i_prebody;
 104         i_prebody = 0;
 105     }
 106     if( p_block->p_buffer + i_body < p_block->p_sys->p_allocated_buffer +
 107         p_block->p_sys->i_allocated_buffer )
 108     {
 109         p_block->i_buffer = i_buffer_size;
 110         i_body = 0;
 111     }
 112
 113     if( i_body > 0 || i_prebody > 0 )
 114     {
 115         block_t *p_rea = block_New( p_block->p_manager, i_buffer_size );
 116
 117         p_rea->i_dts   = p_block->i_dts;
 118         p_rea->i_pts   = p_block->i_pts;
 119         p_rea->i_flags = p_block->i_flags;
 120         p_rea->i_length= p_block->i_length;
 121         p_rea->i_rate  = p_block->i_rate;
 122
 123         memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
 124                 __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
 125
 126         block_Release( p_block );
 127
 128         return p_rea;
 129     }
 130
 131     return p_block;
 132 }
 133
 134 static void BlockRelease( block_t *p_block )
 135 {
 136     free( p_block );
 137 }
 138
 139
 140 /*****************************************************************************
 141  * block_fifo_t management
 142  *****************************************************************************/
 143 block_fifo_t *__block_FifoNew( vlc_object_t *p_obj )
 144 {
 145     block_fifo_t *p_fifo;
 146
 147     p_fifo = malloc( sizeof( vlc_object_t ) );
 148     vlc_mutex_init( p_obj, &p_fifo->lock );
 149     vlc_cond_init( p_obj, &p_fifo->wait );
 150     p_fifo->i_depth = 0;
 151     p_fifo->p_first = NULL;
 152     p_fifo->pp_last = &p_fifo->p_first;
 153
 154     return p_fifo;
 155 }
 156
 157 void block_FifoRelease( block_fifo_t *p_fifo )
 158 {
 159     block_FifoEmpty( p_fifo );
 160     vlc_cond_destroy( &p_fifo->wait );
 161     vlc_mutex_destroy( &p_fifo->lock );
 162     free( p_fifo );
 163 }
 164
 165 void block_FifoEmpty( block_fifo_t *p_fifo )
 166 {
 167     block_t *b;
 168
 169     vlc_mutex_lock( &p_fifo->lock );
 170     for( b = p_fifo->p_first; b != NULL; )
 171     {
 172         block_t *p_next;
 173
 174         p_next = b->p_next;
 175         block_Release( b );
 176         b = p_next;
 177     }
 178
 179     p_fifo->i_depth = 0;
 180     p_fifo->p_first = NULL;
 181     p_fifo->pp_last = &p_fifo->p_first;
 182     vlc_mutex_unlock( &p_fifo->lock );
 183 }
 184
 185 int block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
 186 {
 187     int i_size = 0;
 188     vlc_mutex_lock( &p_fifo->lock );
 189
 190     do
 191     {
 192         i_size += p_block->i_buffer;
 193
 194         *p_fifo->pp_last = p_block;
 195         p_fifo->pp_last = &p_block->p_next;
 196         p_fifo->i_depth++;
 197
 198         p_block = p_block->p_next;
 199
 200     } while( p_block );
 201
 202     /* warn there is data in this fifo */
 203     vlc_cond_signal( &p_fifo->wait );
 204     vlc_mutex_unlock( &p_fifo->lock );
 205
 206     return i_size;
 207 }
 208
 209 block_t *block_FifoGet( block_fifo_t *p_fifo )
 210 {
 211     block_t *b;
 212
 213     vlc_mutex_lock( &p_fifo->lock );
 214
 215     /* We do a while here because there is a race condition in the
 216      * win32 implementation of vlc_cond_wait() (We can't be sure the fifo
 217      * hasn't been emptied again since we were signaled). */
 218     while( p_fifo->p_first == NULL )
 219     {
 220         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 221     }
 222
 223     b = p_fifo->p_first;
 224
 225     p_fifo->p_first = b->p_next;
 226     p_fifo->i_depth--;
 227
 228     if( p_fifo->p_first == NULL )
 229     {
 230         p_fifo->pp_last = &p_fifo->p_first;
 231     }
 232
 233     vlc_mutex_unlock( &p_fifo->lock );
 234
 235     b->p_next = NULL;
 236     return( b );
 237 }
 238
 239 block_t *block_FifoShow( block_fifo_t *p_fifo )
 240 {
 241     block_t *b;
 242
 243     vlc_mutex_lock( &p_fifo->lock );
 244
 245     if( p_fifo->p_first == NULL )
 246     {
 247         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 248     }
 249
 250     b = p_fifo->p_first;
 251
 252     vlc_mutex_unlock( &p_fifo->lock );
 253
 254     return( b );
 255
 256 }
 257