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

   1 /*****************************************************************************
   2  * block.c: Data blocks management functions
   3  *****************************************************************************
   4  * Copyright (C) 2003-2004 the VideoLAN team
   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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, 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     block_sys_t *p_sys;
  53     const int i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + 16;
  54     block_t *p_block =
  55         malloc( sizeof( block_t ) + sizeof( block_sys_t ) + i_alloc );
  56
  57     if( p_block == NULL )
  58         return NULL;
  59
  60     /* Fill opaque data */
  61     p_sys = (block_sys_t*)( (uint8_t*)p_block + sizeof( block_t ) );
  62     p_sys->i_allocated_buffer = i_alloc;
  63     p_sys->p_allocated_buffer = (uint8_t*)p_block + sizeof( block_t ) +
  64         sizeof( block_sys_t );
  65
  66     /* Fill all fields */
  67     p_block->p_next         = NULL;
  68     p_block->p_prev         = NULL;
  69     p_block->i_flags        = 0;
  70     p_block->i_pts          = 0;
  71     p_block->i_dts          = 0;
  72     p_block->i_length       = 0;
  73     p_block->i_rate         = 0;
  74     p_block->i_buffer       = i_size;
  75     p_block->p_buffer       =
  76         &p_sys->p_allocated_buffer[BLOCK_PADDING_SIZE +
  77             16 - ((uintptr_t)p_sys->p_allocated_buffer % 16 )];
  78     p_block->pf_release     = BlockRelease;
  79
  80     /* Is ok, as no comunication between p_vlc */
  81     p_block->p_manager      = VLC_OBJECT( p_obj->p_libvlc );
  82     p_block->p_sys          = p_sys;
  83
  84     return p_block;
  85 }
  86
  87 block_t *block_Realloc( block_t *p_block, int i_prebody, int i_body )
  88 {
  89     int i_buffer_size;
  90
  91     if( p_block->pf_release != BlockRelease )
  92     {
  93         /* Special case when pf_release if overloaded
  94          * TODO if used one day, them implement it in a smarter way */
  95         block_t *p_dup = block_Duplicate( p_block );
  96         block_Release( p_block );
  97         if( !p_dup )
  98             return NULL;
  99
 100         p_block = p_dup;
 101     }
 102
 103     i_buffer_size = i_prebody + i_body;
 104
 105     if( i_body < 0 || i_buffer_size <= 0 )
 106     {
 107         block_Release( p_block );
 108         return NULL;
 109     }
 110
 111     if( p_block->p_buffer - i_prebody > p_block->p_sys->p_allocated_buffer &&
 112         p_block->p_buffer - i_prebody < p_block->p_sys->p_allocated_buffer +
 113         p_block->p_sys->i_allocated_buffer )
 114     {
 115         p_block->p_buffer -= i_prebody;
 116         p_block->i_buffer += i_prebody;
 117         i_prebody = 0;
 118     }
 119     if( p_block->p_buffer + i_body < p_block->p_sys->p_allocated_buffer +
 120         p_block->p_sys->i_allocated_buffer )
 121     {
 122         p_block->i_buffer = i_buffer_size;
 123         i_body = 0;
 124     }
 125
 126     if( i_body > 0 || i_prebody > 0 )
 127     {
 128         block_t *p_rea = block_New( p_block->p_manager, i_buffer_size );
 129
 130         if( p_rea )
 131         {
 132             p_rea->i_dts     = p_block->i_dts;
 133             p_rea->i_pts     = p_block->i_pts;
 134             p_rea->i_flags   = p_block->i_flags;
 135             p_rea->i_length  = p_block->i_length;
 136             p_rea->i_rate    = p_block->i_rate;
 137             p_rea->i_samples = p_block->i_samples;
 138
 139             memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
 140                     __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
 141         }
 142
 143         block_Release( p_block );
 144
 145         return p_rea;
 146     }
 147
 148     return p_block;
 149 }
 150
 151 static void BlockRelease( block_t *p_block )
 152 {
 153     free( p_block );
 154 }
 155
 156
 157 /*****************************************************************************
 158  * block_fifo_t management
 159  *****************************************************************************/
 160 block_fifo_t *__block_FifoNew( vlc_object_t *p_obj )
 161 {
 162     block_fifo_t *p_fifo;
 163
 164     p_fifo = malloc( sizeof( block_fifo_t ) );
 165     vlc_mutex_init( p_obj, &p_fifo->lock );
 166     vlc_cond_init( p_obj, &p_fifo->wait );
 167     p_fifo->i_depth = p_fifo->i_size = 0;
 168     p_fifo->p_first = NULL;
 169     p_fifo->pp_last = &p_fifo->p_first;
 170
 171     return p_fifo;
 172 }
 173
 174 void block_FifoRelease( block_fifo_t *p_fifo )
 175 {
 176     block_FifoEmpty( p_fifo );
 177     vlc_cond_destroy( &p_fifo->wait );
 178     vlc_mutex_destroy( &p_fifo->lock );
 179     free( p_fifo );
 180 }
 181
 182 void block_FifoEmpty( block_fifo_t *p_fifo )
 183 {
 184     block_t *b;
 185
 186     vlc_mutex_lock( &p_fifo->lock );
 187     for( b = p_fifo->p_first; b != NULL; )
 188     {
 189         block_t *p_next;
 190
 191         p_next = b->p_next;
 192         block_Release( b );
 193         b = p_next;
 194     }
 195
 196     p_fifo->i_depth = p_fifo->i_size = 0;
 197     p_fifo->p_first = NULL;
 198     p_fifo->pp_last = &p_fifo->p_first;
 199     vlc_mutex_unlock( &p_fifo->lock );
 200 }
 201
 202 int block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
 203 {
 204     int i_size = 0;
 205     vlc_mutex_lock( &p_fifo->lock );
 206
 207     do
 208     {
 209         i_size += p_block->i_buffer;
 210
 211         *p_fifo->pp_last = p_block;
 212         p_fifo->pp_last = &p_block->p_next;
 213         p_fifo->i_depth++;
 214         p_fifo->i_size += p_block->i_buffer;
 215
 216         p_block = p_block->p_next;
 217
 218     } while( p_block );
 219
 220     /* warn there is data in this fifo */
 221     vlc_cond_signal( &p_fifo->wait );
 222     vlc_mutex_unlock( &p_fifo->lock );
 223
 224     return i_size;
 225 }
 226
 227 block_t *block_FifoGet( block_fifo_t *p_fifo )
 228 {
 229     block_t *b;
 230
 231     vlc_mutex_lock( &p_fifo->lock );
 232
 233     /* We do a while here because there is a race condition in the
 234      * win32 implementation of vlc_cond_wait() (We can't be sure the fifo
 235      * hasn't been emptied again since we were signaled). */
 236     while( p_fifo->p_first == NULL )
 237     {
 238         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 239     }
 240
 241     b = p_fifo->p_first;
 242
 243     p_fifo->p_first = b->p_next;
 244     p_fifo->i_depth--;
 245     p_fifo->i_size -= b->i_buffer;
 246
 247     if( p_fifo->p_first == NULL )
 248     {
 249         p_fifo->pp_last = &p_fifo->p_first;
 250     }
 251
 252     vlc_mutex_unlock( &p_fifo->lock );
 253
 254     b->p_next = NULL;
 255     return b;
 256 }
 257
 258 block_t *block_FifoShow( block_fifo_t *p_fifo )
 259 {
 260     block_t *b;
 261
 262     vlc_mutex_lock( &p_fifo->lock );
 263
 264     if( p_fifo->p_first == NULL )
 265     {
 266         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 267     }
 268
 269     b = p_fifo->p_first;
 270
 271     vlc_mutex_unlock( &p_fifo->lock );
 272
 273     return( b );
 274
 275 }
 276