Alc/null.c

   1 /**
   2  * OpenAL cross platform audio library
   3  * Copyright (C) 2010 by Chris Robinson
   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., 59 Temple Place - Suite 330,
  17  *  Boston, MA  02111-1307, USA.
  18  * Or go to http://www.gnu.org/copyleft/lgpl.html
  19  */
  20
  21 #include "config.h"
  22
  23 #include <stdlib.h>
  24 #include "alMain.h"
  25 #include "AL/al.h"
  26 #include "AL/alc.h"
  27
  28
  29 typedef struct {
  30     ALvoid *buffer;
  31     ALuint size;
  32
  33     volatile int killNow;
  34     ALvoid *thread;
  35 } null_data;
  36
  37
  38 static const ALCchar nullDevice[] = "No Output";
  39
  40 static ALuint NullProc(ALvoid *ptr)
  41 {
  42     ALCdevice *Device = (ALCdevice*)ptr;
  43     null_data *data = (null_data*)Device->ExtraData;
  44     ALuint now, start;
  45     ALuint64 avail, done;
  46     const ALuint restTime = (ALuint64)Device->UpdateSize * 1000 /
  47                             Device->Frequency / 2;
  48
  49     done = 0;
  50     start = timeGetTime();
  51     while(!data->killNow && Device->Connected)
  52     {
  53         now = timeGetTime();
  54
  55         avail = (ALuint64)(now-start) * Device->Frequency / 1000;
  56         if(avail < done)
  57         {
  58             AL_PRINT("Timer wrapped\n");
  59             aluHandleDisconnect(Device);
  60             break;
  61         }
  62         if(avail-done < Device->UpdateSize)
  63         {
  64             Sleep(restTime);
  65             continue;
  66         }
  67
  68         while(avail-done >= Device->UpdateSize)
  69         {
  70             aluMixData(Device, data->buffer, Device->UpdateSize);
  71             done += Device->UpdateSize;
  72         }
  73     }
  74
  75     return 0;
  76 }
  77
  78 static ALCboolean null_open_playback(ALCdevice *device, const ALCchar *deviceName)
  79 {
  80     null_data *data;
  81
  82     if(!deviceName)
  83         deviceName = nullDevice;
  84     else if(strcmp(deviceName, nullDevice) != 0)
  85         return ALC_FALSE;
  86
  87     data = (null_data*)calloc(1, sizeof(*data));
  88
  89     device->szDeviceName = strdup(deviceName);
  90     device->ExtraData = data;
  91     return ALC_TRUE;
  92 }
  93
  94 static void null_close_playback(ALCdevice *device)
  95 {
  96     null_data *data = (null_data*)device->ExtraData;
  97
  98     free(data);
  99     device->ExtraData = NULL;
 100 }
 101
 102 static ALCboolean null_reset_playback(ALCdevice *device)
 103 {
 104     null_data *data = (null_data*)device->ExtraData;
 105
 106     data->size = device->UpdateSize * aluFrameSizeFromFormat(device->Format);
 107     data->buffer = malloc(data->size);
 108     if(!data->buffer)
 109     {
 110         AL_PRINT("buffer malloc failed\n");
 111         return ALC_FALSE;
 112     }
 113     SetDefaultWFXChannelOrder(device);
 114
 115     data->thread = StartThread(NullProc, device);
 116     if(data->thread == NULL)
 117     {
 118         free(data->buffer);
 119         data->buffer = NULL;
 120         return ALC_FALSE;
 121     }
 122
 123     return ALC_TRUE;
 124 }
 125
 126 static void null_stop_playback(ALCdevice *device)
 127 {
 128     null_data *data = (null_data*)device->ExtraData;
 129
 130     if(!data->thread)
 131         return;
 132
 133     data->killNow = 1;
 134     StopThread(data->thread);
 135     data->thread = NULL;
 136
 137     data->killNow = 0;
 138
 139     free(data->buffer);
 140     data->buffer = NULL;
 141 }
 142
 143
 144 static ALCboolean null_open_capture(ALCdevice *device, const ALCchar *deviceName)
 145 {
 146     (void)device;
 147     (void)deviceName;
 148     return ALC_FALSE;
 149 }
 150
 151
 152 BackendFuncs null_funcs = {
 153     null_open_playback,
 154     null_close_playback,
 155     null_reset_playback,
 156     null_stop_playback,
 157     null_open_capture,
 158     NULL,
 159     NULL,
 160     NULL,
 161     NULL,
 162     NULL
 163 };
 164
 165 void alc_null_init(BackendFuncs *func_list)
 166 {
 167     *func_list = null_funcs;
 168 }
 169
 170 void alc_null_deinit(void)
 171 {
 172 }
 173
 174 void alc_null_probe(int type)
 175 {
 176     if(type == DEVICE_PROBE)
 177         AppendDeviceList(nullDevice);
 178     else if(type == ALL_DEVICE_PROBE)
 179         AppendAllDeviceList(nullDevice);
 180 }