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     size_t      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, size_t 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 size_t 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_sys          = p_sys;
  80
  81     return p_block;
  82 }
  83
  84 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
  85 {
  86     ssize_t i_buffer_size;
  87
  88     if( p_block->pf_release != BlockRelease )
  89     {
  90         /* Special case when pf_release if overloaded
  91          * TODO if used one day, them implement it in a smarter way */
  92         block_t *p_dup = block_Duplicate( p_block );
  93         block_Release( p_block );
  94         if( !p_dup )
  95             return NULL;
  96
  97         p_block = p_dup;
  98     }
  99
 100     i_buffer_size = i_prebody + i_body;
 101
 102     if( i_buffer_size <= 0 )
 103     {
 104         block_Release( p_block );
 105         return NULL;
 106     }
 107
 108     if( p_block->p_buffer - i_prebody > p_block->p_sys->p_allocated_buffer &&
 109         p_block->p_buffer - i_prebody < p_block->p_sys->p_allocated_buffer +
 110         p_block->p_sys->i_allocated_buffer )
 111     {
 112         p_block->p_buffer -= i_prebody;
 113         p_block->i_buffer += i_prebody;
 114         i_prebody = 0;
 115     }
 116     if( p_block->p_buffer + i_body < p_block->p_sys->p_allocated_buffer +
 117         p_block->p_sys->i_allocated_buffer )
 118     {
 119         p_block->i_buffer = i_buffer_size;
 120         i_body = 0;
 121     }
 122
 123     if( i_body > 0 || i_prebody > 0 )
 124     {
 125         block_t *p_rea = block_New( NULL, i_buffer_size );
 126
 127         if( p_rea )
 128         {
 129             p_rea->i_dts     = p_block->i_dts;
 130             p_rea->i_pts     = p_block->i_pts;
 131             p_rea->i_flags   = p_block->i_flags;
 132             p_rea->i_length  = p_block->i_length;
 133             p_rea->i_rate    = p_block->i_rate;
 134             p_rea->i_samples = p_block->i_samples;
 135
 136             memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
 137                     __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
 138         }
 139
 140         block_Release( p_block );
 141
 142         return p_rea;
 143     }
 144
 145     return p_block;
 146 }
 147
 148 static void BlockRelease( block_t *p_block )
 149 {
 150     free( p_block );
 151 }
 152
 153
 154 /*****************************************************************************
 155  * block_fifo_t management
 156  *****************************************************************************/
 157 struct block_fifo_t
 158 {
 159     vlc_mutex_t         lock;                         /* fifo data lock */
 160     vlc_cond_t          wait;         /* fifo data conditional variable */
 161
 162     block_t             *p_first;
 163     block_t             **pp_last;
 164     size_t              i_depth;
 165     size_t              i_size;
 166     vlc_bool_t          b_force_wake;
 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     if( !p_fifo ) return NULL;
 175     vlc_mutex_init( p_obj, &p_fifo->lock );
 176     vlc_cond_init( p_obj, &p_fifo->wait );
 177     p_fifo->p_first = NULL;
 178     p_fifo->pp_last = &p_fifo->p_first;
 179     p_fifo->i_depth = p_fifo->i_size = 0;
 180     p_fifo->b_force_wake = VLC_FALSE;
 181
 182     return p_fifo;
 183 }
 184
 185 void block_FifoRelease( block_fifo_t *p_fifo )
 186 {
 187     block_FifoEmpty( p_fifo );
 188     vlc_cond_destroy( &p_fifo->wait );
 189     vlc_mutex_destroy( &p_fifo->lock );
 190     free( p_fifo );
 191 }
 192
 193 void block_FifoEmpty( block_fifo_t *p_fifo )
 194 {
 195     block_t *b;
 196
 197     vlc_mutex_lock( &p_fifo->lock );
 198     for( b = p_fifo->p_first; b != NULL; )
 199     {
 200         block_t *p_next;
 201
 202         p_next = b->p_next;
 203         block_Release( b );
 204         b = p_next;
 205     }
 206
 207     p_fifo->i_depth = p_fifo->i_size = 0;
 208     p_fifo->p_first = NULL;
 209     p_fifo->pp_last = &p_fifo->p_first;
 210     vlc_mutex_unlock( &p_fifo->lock );
 211 }
 212
 213 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
 214 {
 215     size_t i_size = 0;
 216     vlc_mutex_lock( &p_fifo->lock );
 217
 218     do
 219     {
 220         i_size += p_block->i_buffer;
 221
 222         *p_fifo->pp_last = p_block;
 223         p_fifo->pp_last = &p_block->p_next;
 224         p_fifo->i_depth++;
 225         p_fifo->i_size += p_block->i_buffer;
 226
 227         p_block = p_block->p_next;
 228
 229     } while( p_block );
 230
 231     /* warn there is data in this fifo */
 232     vlc_cond_signal( &p_fifo->wait );
 233     vlc_mutex_unlock( &p_fifo->lock );
 234
 235     return i_size;
 236 }
 237
 238 void block_FifoWake( block_fifo_t *p_fifo )
 239 {
 240     vlc_mutex_lock( &p_fifo->lock );
 241     if( p_fifo->p_first == NULL )
 242         p_fifo->b_force_wake = VLC_TRUE;
 243     vlc_cond_signal( &p_fifo->wait );
 244     vlc_mutex_unlock( &p_fifo->lock );
 245 }
 246
 247 block_t *block_FifoGet( block_fifo_t *p_fifo )
 248 {
 249     block_t *b;
 250
 251     vlc_mutex_lock( &p_fifo->lock );
 252
 253     /* Remember vlc_cond_wait() may cause spurious wakeups
 254      * (on both Win32 and POSIX) */
 255     while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
 256     {
 257         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 258     }
 259
 260     b = p_fifo->p_first;
 261
 262     p_fifo->b_force_wake = VLC_FALSE;
 263     if( b == NULL )
 264     {
 265         /* Forced wakeup */
 266         vlc_mutex_unlock( &p_fifo->lock );
 267         return NULL;
 268     }
 269
 270     p_fifo->p_first = b->p_next;
 271     p_fifo->i_depth--;
 272     p_fifo->i_size -= b->i_buffer;
 273
 274     if( p_fifo->p_first == NULL )
 275     {
 276         p_fifo->pp_last = &p_fifo->p_first;
 277     }
 278
 279     vlc_mutex_unlock( &p_fifo->lock );
 280
 281     b->p_next = NULL;
 282     return b;
 283 }
 284
 285 block_t *block_FifoShow( block_fifo_t *p_fifo )
 286 {
 287     block_t *b;
 288
 289     vlc_mutex_lock( &p_fifo->lock );
 290
 291     if( p_fifo->p_first == NULL )
 292     {
 293         vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
 294     }
 295
 296     b = p_fifo->p_first;
 297
 298     vlc_mutex_unlock( &p_fifo->lock );
 299
 300     return( b );
 301 }
 302
 303 size_t block_FifoSize( const block_fifo_t *p_fifo )
 304 {
 305     return p_fifo->i_size;
 306 }
 307
 308 size_t block_FifoCount( const block_fifo_t *p_fifo )
 309 {
 310     return p_fifo->i_depth;
 311 }