OpenAL32/alThunk.c

   1 /**
   2  * OpenAL cross platform audio library
   3  * Copyright (C) 1999-2007 by authors.
   4  * This library is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU Library General Public
   6  *  License as published by the Free Software Foundation; either
   7  *  version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *  Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  *  License along with this library; if not, write to the
  16  *  Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  * Or go to http://www.gnu.org/copyleft/lgpl.html
  19  */
  20
  21 #include "config.h"
  22
  23 #include <stdlib.h>
  24
  25 #include "alMain.h"
  26 #include "alThunk.h"
  27
  28 #include "almalloc.h"
  29
  30
  31 static ATOMIC_FLAG *ThunkArray;
  32 static ALsizei      ThunkArraySize;
  33 static RWLock ThunkLock;
  34
  35 void ThunkInit(void)
  36 {
  37     RWLockInit(&ThunkLock);
  38     ThunkArraySize = 1024;
  39     ThunkArray = al_calloc(16, ThunkArraySize * sizeof(*ThunkArray));
  40 }
  41
  42 void ThunkExit(void)
  43 {
  44     al_free(ThunkArray);
  45     ThunkArray = NULL;
  46     ThunkArraySize = 0;
  47 }
  48
  49 ALenum NewThunkEntry(ALuint *index)
  50 {
  51     void *NewList;
  52     ALsizei i;
  53
  54     ReadLock(&ThunkLock);
  55     for(i = 0;i < ThunkArraySize;i++)
  56     {
  57         if(!ATOMIC_FLAG_TEST_AND_SET(&ThunkArray[i], almemory_order_acq_rel))
  58         {
  59             ReadUnlock(&ThunkLock);
  60             *index = i+1;
  61             return AL_NO_ERROR;
  62         }
  63     }
  64     ReadUnlock(&ThunkLock);
  65
  66     WriteLock(&ThunkLock);
  67     /* Double-check that there's still no free entries, in case another
  68      * invocation just came through and increased the size of the array.
  69      */
  70     for(;i < ThunkArraySize;i++)
  71     {
  72         if(!ATOMIC_FLAG_TEST_AND_SET(&ThunkArray[i], almemory_order_acq_rel))
  73         {
  74             WriteUnlock(&ThunkLock);
  75             *index = i+1;
  76             return AL_NO_ERROR;
  77         }
  78     }
  79
  80     NewList = al_calloc(16, ThunkArraySize*2 * sizeof(*ThunkArray));
  81     if(!NewList)
  82     {
  83         WriteUnlock(&ThunkLock);
  84         ERR("Realloc failed to increase to %u entries!\n", ThunkArraySize*2);
  85         return AL_OUT_OF_MEMORY;
  86     }
  87     memcpy(NewList, ThunkArray, ThunkArraySize*sizeof(*ThunkArray));
  88     al_free(ThunkArray);
  89     ThunkArray = NewList;
  90     ThunkArraySize *= 2;
  91
  92     ATOMIC_FLAG_TEST_AND_SET(&ThunkArray[i], almemory_order_seq_cst);
  93     *index = ++i;
  94
  95     for(;i < ThunkArraySize;i++)
  96         ATOMIC_FLAG_CLEAR(&ThunkArray[i], almemory_order_relaxed);
  97     WriteUnlock(&ThunkLock);
  98
  99     return AL_NO_ERROR;
 100 }
 101
 102 void FreeThunkEntry(ALuint index)
 103 {
 104     ReadLock(&ThunkLock);
 105     if(index > 0 && (ALsizei)index <= ThunkArraySize)
 106         ATOMIC_FLAG_CLEAR(&ThunkArray[index-1], almemory_order_release);
 107     ReadUnlock(&ThunkLock);
 108 }