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 <vlc/vlc.h>
  28 #include "vlc_block.h"
  29
  30 /*****************************************************************************
  31  * Block functions.
  32  *****************************************************************************/
  33 /* private */
  34 struct block_sys_t
  35 {
  36     uint8_t     *p_allocated_buffer;
  37     int         i_allocated_buffer;
  38 };
  39
  40 #define BLOCK_PADDING_SIZE 32
  41 static void BlockRelease( block_t * );
  42
  43 block_t *__block_New( vlc_object_t *p_obj, int i_size )
  44 {
  45     /* We do only one malloc
  46      * TODO bench if doing 2 malloc but keeping a pool of buffer is better
  47      * 16 -> align on 16
  48      * 2 * BLOCK_PADDING_SIZE -> pre + post padding
  49      */
  50     block_sys_t *p_sys;
  51     const int i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + 16;
  52     block_t *p_block =
  53         malloc( sizeof( block_t ) + sizeof( block_sys_t ) + i_alloc );
  54
  55     if( p_block == NULL )
  56         return NULL;
  57
  58     /* Fill opaque data */
  59     p_sys = (block_sys_t*)( (uint8_t*)p_block + sizeof( block_t ) );
  60     p_sys->i_allocated_buffer = i_alloc;
  61     p_sys->p_allocated_buffer = (uint8_t*)p_block + sizeof( block_t ) +
  62         sizeof( block_sys_t );
  63
  64     /* Fill all fields */
  65     p_block->p_next         = NULL;
  66     p_block->p_prev         = NULL;
  67     p_block->i_flags        = 0;
  68     p_block->i_pts          = 0;
  69     p_block->i_dts          = 0;
  70     p_block->i_length       = 0;
  71     p_block->i_rate         = 0;
  72     p_block->i_buffer       = i_size;
  73     p_block->p_buffer       =
  74         &p_sys->p_allocated_buffer[BLOCK_PADDING_SIZE +
  75             16 - ((uintptr_t)p_sys->p_allocated_buffer % 16 )];
  76     p_block->pf_release     = BlockRelease;
  77
  78     /* Is ok, as no comunication between p_vlc */
  79     p_block->p_manager      = VLC_OBJECT( p_obj->p_libvlc );
  80     p_block->p_sys          = p_sys;
  81
  82     return p_block;
  83 }
  84
  85 block_t *block_Realloc( block_t *p_block, int i_prebody, int i_body )
  86 {
  87     int i_buffer_size;
  88
  89     if( p_block->pf_release != BlockRelease )
  90     {
  91         /* Special case when pf_release if overloaded
  92          * TODO if used one day, them implement it in a smarter way */
  93         block_t *p_dup = block_Duplicate( p_block );
  94         block_Release( p_block );
  95         if( !p_dup )
  96             return NULL;
  97
  98         p_block = p_dup;
  99     }
 100
 101     i_buffer_size = i_prebody + i_body;
 102
 103     if( i_body < 0 || i_buffer_size <= 0 )
 104     {
 105         block_Release( p_block );
 106         return NULL;
 107     }
 108
 109     if( p_block->p_buffer - i_prebody > p_block->p_sys->p_allocated_buffer &&
 110         p_block->p_buffer - i_prebody < p_block->p_sys->p_allocated_buffer +
 111         p_block->p_sys->i_allocated_buffer )
 112     {
 113         p_block->p_buffer -= i_prebody;
 114         p_block->i_buffer += i_prebody;
 115         i_prebody = 0;
 116     }
 117     if( p_block->p_buffer + i_body < p_block->p_sys->p_allocated_buffer +
 118         p_block->p_sys->i_allocated_buffer )
 119     {
 120         p_block->i_buffer = i_buffer_size;
 121         i_body = 0;
 122     }
 123
 124     if( i_body > 0 || i_prebody > 0 )
 125     {
 126         block_t *p_rea = block_New( p_block->p_manager, i_buffer_size );
 127
 128         if( p_rea )
 129         {
 130             p_rea->i_dts     = p_block->i_dts;
 131             p_rea->i_pts     = p_block->i_pts;
 132             p_rea->i_flags   = p_block->i_flags;
 133             p_rea->i_length  = p_block->i_length;
 134             p_rea->i_rate    = p_block->i_rate;
 135             p_rea->i_samples = p_block->i_samples;
 136
 137             memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
 138                     __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
 139         }
 140
 141         block_Release( p_block );
 142
 143         return p_rea;
 144     }
 145
 146     return p_block;
 147 }
 148
 149 static void BlockRelease( block_t *p_block )
 150 {
 151     free( p_block );
 152 }
 153
 154
 155 /*****************************************************************************
 156  * block_fifo_t management
 157  *****************************************************************************/
 158 struct block_fifo_t
 159 {
 160     vlc_mutex_t         lock;                         /* fifo data lock */
 161     vlc_cond_t          wait;         /* fifo data conditional variable */
 162
 163     size_t              i_depth;
 164     block_t             *p_first;
 165     block_t             **pp_last;
 166     size_t              i_size;
 167 };
 168
 169 block_fifo_t *__block_FifoNew( vlc_object_t *p_obj )
 170 {
 171     block_fifo_t *p_fifo;
 172
 173     p_fifo = malloc( sizeof( block_fifo_t ) );
 174     vlc_mutex_init( p_obj, &p_fifo->lock );
 175     vlc_cond_init( p_obj, &p_fifo->wait );
 176     p_fifo->i_depth = p_fifo->i_size = 0;
 177     p_fifo->p_first = NULL;
 178     p_fifo->pp_last = &p_fifo->p_first;
 179
 180     return p_fifo;
 181 }
 182
 183 void block_FifoRelease( block_fifo_t *p_fifo )
 184 {
 185     block_FifoEmpty( p_fifo );
 186     vlc_cond_destroy( &p_fifo->wait );
 187     vlc_mutex_destroy( &p_fifo->lock );
 188     free( p_fifo );
 189 }
 190
 191 void block_FifoEmpty( block_fifo_t *p_fifo )
 192 {
 193     block_t *b;
 194
 195     vlc_mutex_lock( &p_fifo->lock );
 196     for( b = p_fifo->p_first; b != NULL; )
 197     {
 198         block_t *p_next;
 199
 200         p_next = b->p_next;
 201         block_Release( b );
 202         b = p_next;
 203     }
 204
 205     p_fifo->i_depth = p_fifo->i_size = 0;
 206     p_fifo->p_first = NULL;
 207     p_fifo->pp_last = &p_fifo->p_first;
 208     vlc_mutex_unlock( &p_fifo->lock );
 209 }
 210
 211 int block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
 212 {
 213     int i_size = 0;
 214     vlc_mutex_lock( &p_fifo->lock );
 215
 216     do
 217     {
 218         i_size += p_block->i_buffer;
 219
 220         *p_fifo->pp_last = p_block;
 221         p_fifo->pp_last = &p_block->p_next;
 222         p_fifo->i_depth++;
 223         p_fifo->i_size += p_block->i_buffer;
 224
 225         p_block = p_block->p_next;
 226
 227     } while( p_block );
 228
 229     /* warn there is data in this fifo */
 230     vlc_cond_signal( &p_fifo->wait );
 231     vlc_mutex_unlock( &p_fifo->lock );
 232
 233     return i_size;
 234 }
 235
 236 block_t *block_FifoGet( block_fifo_t *p_fifo )
 237 {
 238     block_t *b;
 239
 240     vlc_mutex_lock( &p_fifo->lock );
 241
 242     /* We do a while here because there is a race condition in the
 243      * win32 implementation of vlc_cond_wait() (We can't be sure the fifo
 244      * hasn't been emptied again since we were signaled). */
 245     while( 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     p_fifo->p_first = b->p_next;
 253     p_fifo->i_depth--;
 254     p_fifo->i_size -= b->i_buffer;
 255
 256     if( p_fifo->p_first == NULL )
 257     {
 258         p_fifo->pp_last = &p_fifo->p_first;
 259     }
 260
 261     vlc_mutex_unlock( &p_fifo->lock );
 262
 263     b->p_next = NULL;
 264     return b;
 265 }
 266
 267 block_t *block_FifoShow( block_fifo_t *p_fifo )
 268 {
 269     block_t *b;
 270
 271     vlc_mutex_lock( &p_fifo->lock );
 272
 273     if( p_fifo->p_first == NULL )
 274     {
 275         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 276     }
 277
 278     b = p_fifo->p_first;
 279
 280     vlc_mutex_unlock( &p_fifo->lock );
 281
 282     return( b );
 283 }
 284
 285 size_t block_FifoSize( const block_fifo_t *p_fifo )
 286 {
 287     return p_fifo->i_size;
 288 }
 289
 290 size_t block_FifoCount( const block_fifo_t *p_fifo )
 291 {
 292     return p_fifo->i_depth;
 293 }