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