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/**
* OpenAL cross platform audio library
* Copyright (C) 2010 by Chris Robinson
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
* Or go to http://www.gnu.org/copyleft/lgpl.html
*/
#include "config.h"
#include <stdlib.h>
#include "alMain.h"
#include "AL/al.h"
#include "AL/alc.h"
typedef struct {
volatile int killNow;
ALvoid *thread;
} null_data;
static const ALCchar nullDevice[] = "No Output";
static ALuint NullProc(ALvoid *ptr)
{
ALCdevice *Device = (ALCdevice*)ptr;
null_data *data = (null_data*)Device->ExtraData;
ALuint now, start;
ALuint64 avail, done;
const ALuint restTime = (ALuint64)Device->UpdateSize * 1000 /
Device->Frequency / 2;
done = 0;
start = timeGetTime();
while(!data->killNow && Device->Connected)
{
now = timeGetTime();
avail = (ALuint64)(now-start) * Device->Frequency / 1000;
if(avail < done)
{
/* Timer wrapped (50 days???). Add the remainder of the cycle to
* the available count and reset the number of samples done */
avail += ((ALuint64)1<<32)*Device->Frequency/1000 - done;
done = 0;
}
if(avail-done < Device->UpdateSize)
{
Sleep(restTime);
continue;
}
while(avail-done >= Device->UpdateSize)
{
aluMixData(Device, NULL, Device->UpdateSize);
done += Device->UpdateSize;
}
}
return 0;
}
static ALCenum null_open_playback(ALCdevice *device, const ALCchar *deviceName)
{
null_data *data;
if(!deviceName)
deviceName = nullDevice;
else if(strcmp(deviceName, nullDevice) != 0)
return ALC_INVALID_VALUE;
data = (null_data*)calloc(1, sizeof(*data));
device->DeviceName = strdup(deviceName);
device->ExtraData = data;
return ALC_NO_ERROR;
}
static void null_close_playback(ALCdevice *device)
{
null_data *data = (null_data*)device->ExtraData;
free(data);
device->ExtraData = NULL;
}
static ALCboolean null_reset_playback(ALCdevice *device)
{
SetDefaultWFXChannelOrder(device);
return ALC_TRUE;
}
static ALCboolean null_start_playback(ALCdevice *device)
{
null_data *data = (null_data*)device->ExtraData;
data->thread = StartThread(NullProc, device);
if(data->thread == NULL)
return ALC_FALSE;
return ALC_TRUE;
}
static void null_stop_playback(ALCdevice *device)
{
null_data *data = (null_data*)device->ExtraData;
if(!data->thread)
return;
data->killNow = 1;
StopThread(data->thread);
data->thread = NULL;
data->killNow = 0;
}
static const BackendFuncs null_funcs = {
null_open_playback,
null_close_playback,
null_reset_playback,
null_start_playback,
null_stop_playback,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL
};
ALCboolean alc_null_init(BackendFuncs *func_list)
{
*func_list = null_funcs;
return ALC_TRUE;
}
void alc_null_deinit(void)
{
}
void alc_null_probe(enum DevProbe type)
{
switch(type)
{
case ALL_DEVICE_PROBE:
AppendAllDeviceList(nullDevice);
break;
case CAPTURE_DEVICE_PROBE:
break;
}
}
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