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     ALuint startTime;
  34     ALuint64 baseTime;
  35
  36     volatile int killNow;
  37     ALvoid *thread;
  38 } null_data;
  39
  40
  41 static const ALCchar nullDevice[] = "No Output";
  42
  43 static ALuint NullProc(ALvoid *ptr)
  44 {
  45     ALCdevice *Device = (ALCdevice*)ptr;
  46     null_data *data = (null_data*)Device->ExtraData;
  47     ALuint now, start;
  48     ALuint64 avail, done;
  49     const ALuint restTime = (ALuint64)Device->UpdateSize * 1000 /
  50                             Device->Frequency / 2;
  51
  52     done = 0;
  53     start = data->startTime;
  54     while(!data->killNow && Device->Connected)
  55     {
  56         now = timeGetTime();
  57
  58         avail = (ALuint64)(now-start) * Device->Frequency / 1000;
  59         if(avail < done)
  60         {
  61             AL_PRINT("Timer wrapped\n");
  62             aluHandleDisconnect(Device);
  63             break;
  64         }
  65         if(avail-done < Device->UpdateSize)
  66         {
  67             Sleep(restTime);
  68             continue;
  69         }
  70
  71         while(avail-done >= Device->UpdateSize)
  72         {
  73             aluMixData(Device, data->buffer, Device->UpdateSize);
  74             done += Device->UpdateSize;
  75         }
  76     }
  77
  78     return 0;
  79 }
  80
  81 static ALCboolean null_open_playback(ALCdevice *device, const ALCchar *deviceName)
  82 {
  83     null_data *data;
  84
  85     if(!deviceName)
  86         deviceName = nullDevice;
  87     else if(strcmp(deviceName, nullDevice) != 0)
  88         return ALC_FALSE;
  89
  90     data = (null_data*)calloc(1, sizeof(*data));
  91
  92     device->szDeviceName = strdup(deviceName);
  93     device->ExtraData = data;
  94     return ALC_TRUE;
  95 }
  96
  97 static void null_close_playback(ALCdevice *device)
  98 {
  99     null_data *data = (null_data*)device->ExtraData;
 100
 101     free(data);
 102     device->ExtraData = NULL;
 103 }
 104
 105 static ALCboolean null_reset_playback(ALCdevice *device)
 106 {
 107     null_data *data = (null_data*)device->ExtraData;
 108
 109     data->size = device->UpdateSize * aluFrameSizeFromFormat(device->Format);
 110     data->buffer = malloc(data->size);
 111     if(!data->buffer)
 112     {
 113         AL_PRINT("buffer malloc failed\n");
 114         return ALC_FALSE;
 115     }
 116     SetDefaultWFXChannelOrder(device);
 117
 118     device->TimeRes = 1000000;
 119
 120     data->startTime = timeGetTime();
 121     data->thread = StartThread(NullProc, device);
 122     if(data->thread == NULL)
 123     {
 124         free(data->buffer);
 125         data->buffer = NULL;
 126         return ALC_FALSE;
 127     }
 128
 129     return ALC_TRUE;
 130 }
 131
 132 static void null_stop_playback(ALCdevice *device)
 133 {
 134     null_data *data = (null_data*)device->ExtraData;
 135     ALuint ext;
 136
 137     if(!data->thread)
 138         return;
 139
 140     data->killNow = 1;
 141     StopThread(data->thread);
 142     data->thread = NULL;
 143
 144     data->killNow = 0;
 145
 146     ext = timeGetTime() - data->startTime;
 147     data->baseTime += (ALuint64)ext * 1000000;
 148
 149     free(data->buffer);
 150     data->buffer = NULL;
 151 }
 152
 153
 154 static ALCboolean null_open_capture(ALCdevice *device, const ALCchar *deviceName)
 155 {
 156     (void)device;
 157     (void)deviceName;
 158     return ALC_FALSE;
 159 }
 160
 161 static ALuint64 null_get_time(ALCdevice *Device)
 162 {
 163     null_data *data = (null_data*)Device->ExtraData;
 164     ALuint ext = 0;
 165     if(data->thread)
 166         ext = timeGetTime() - data->startTime;
 167     return data->baseTime + ((ALuint64)ext * 1000000);
 168 }
 169
 170
 171 BackendFuncs null_funcs = {
 172     null_open_playback,
 173     null_close_playback,
 174     null_reset_playback,
 175     null_stop_playback,
 176     null_open_capture,
 177     NULL,
 178     NULL,
 179     NULL,
 180     NULL,
 181     NULL,
 182     null_get_time
 183 };
 184
 185 void alc_null_init(BackendFuncs *func_list)
 186 {
 187     *func_list = null_funcs;
 188 }
 189
 190 void alc_null_deinit(void)
 191 {
 192 }
 193
 194 void alc_null_probe(int type)
 195 {
 196     if(type == DEVICE_PROBE)
 197         AppendDeviceList(nullDevice);
 198     else if(type == ALL_DEVICE_PROBE)
 199         AppendAllDeviceList(nullDevice);
 200 }