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
  29 static ATOMIC(ALenum) *ThunkArray;
  30 static ALuint          ThunkArraySize;
  31 static RWLock ThunkLock;
  32
  33 void ThunkInit(void)
  34 {
  35     RWLockInit(&ThunkLock);
  36     ThunkArraySize = 1;
  37     ThunkArray = al_calloc(16, ThunkArraySize * sizeof(*ThunkArray));
  38 }
  39
  40 void ThunkExit(void)
  41 {
  42     al_free(ThunkArray);
  43     ThunkArray = NULL;
  44     ThunkArraySize = 0;
  45 }
  46
  47 ALenum NewThunkEntry(ALuint *index)
  48 {
  49     void *NewList;
  50     ALuint i;
  51
  52     ReadLock(&ThunkLock);
  53     for(i = 0;i < ThunkArraySize;i++)
  54     {
  55         if(ATOMIC_EXCHANGE(ALenum, &ThunkArray[i], AL_TRUE) == AL_FALSE)
  56         {
  57             ReadUnlock(&ThunkLock);
  58             *index = i+1;
  59             return AL_NO_ERROR;
  60         }
  61     }
  62     ReadUnlock(&ThunkLock);
  63
  64     WriteLock(&ThunkLock);
  65     /* Double-check that there's still no free entries, in case another
  66      * invocation just came through and increased the size of the array.
  67      */
  68     for(;i < ThunkArraySize;i++)
  69     {
  70         if(ATOMIC_EXCHANGE(ALenum, &ThunkArray[i], AL_TRUE) == AL_FALSE)
  71         {
  72             WriteUnlock(&ThunkLock);
  73             *index = i+1;
  74             return AL_NO_ERROR;
  75         }
  76     }
  77
  78     NewList = al_calloc(16, ThunkArraySize*2 * sizeof(*ThunkArray));
  79     if(!NewList)
  80     {
  81         WriteUnlock(&ThunkLock);
  82         ERR("Realloc failed to increase to %u entries!\n", ThunkArraySize*2);
  83         return AL_OUT_OF_MEMORY;
  84     }
  85     memcpy(NewList, ThunkArray, ThunkArraySize*sizeof(*ThunkArray));
  86     al_free(ThunkArray);
  87     ThunkArray = NewList;
  88     ThunkArraySize *= 2;
  89
  90     ATOMIC_STORE(&ThunkArray[i], AL_TRUE);
  91     WriteUnlock(&ThunkLock);
  92
  93     *index = i+1;
  94     return AL_NO_ERROR;
  95 }
  96
  97 void FreeThunkEntry(ALuint index)
  98 {
  99     ReadLock(&ThunkLock);
 100     if(index > 0 && index <= ThunkArraySize)
 101         ATOMIC_STORE(&ThunkArray[index-1], AL_FALSE);
 102     ReadUnlock(&ThunkLock);
 103 }