Alc/backends/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.,
  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 #ifdef HAVE_WINDOWS_H
  25 #include <windows.h>
  26 #endif
  27
  28 #include "alMain.h"
  29 #include "alu.h"
  30 #include "threads.h"
  31 #include "compat.h"
  32
  33 #include "backends/base.h"
  34
  35
  36 typedef struct ALCnullBackend {
  37     DERIVE_FROM_TYPE(ALCbackend);
  38
  39     volatile int killNow;
  40     althrd_t thread;
  41 } ALCnullBackend;
  42
  43 static int ALCnullBackend_mixerProc(void *ptr);
  44
  45 static void ALCnullBackend_Construct(ALCnullBackend *self, ALCdevice *device);
  46 static DECLARE_FORWARD(ALCnullBackend, ALCbackend, void, Destruct)
  47 static ALCenum ALCnullBackend_open(ALCnullBackend *self, const ALCchar *name);
  48 static void ALCnullBackend_close(ALCnullBackend *self);
  49 static ALCboolean ALCnullBackend_reset(ALCnullBackend *self);
  50 static ALCboolean ALCnullBackend_start(ALCnullBackend *self);
  51 static void ALCnullBackend_stop(ALCnullBackend *self);
  52 static DECLARE_FORWARD2(ALCnullBackend, ALCbackend, ALCenum, captureSamples, void*, ALCuint)
  53 static DECLARE_FORWARD(ALCnullBackend, ALCbackend, ALCuint, availableSamples)
  54 static DECLARE_FORWARD(ALCnullBackend, ALCbackend, ClockLatency, getClockLatency)
  55 static DECLARE_FORWARD(ALCnullBackend, ALCbackend, void, lock)
  56 static DECLARE_FORWARD(ALCnullBackend, ALCbackend, void, unlock)
  57 DECLARE_DEFAULT_ALLOCATORS(ALCnullBackend)
  58
  59 DEFINE_ALCBACKEND_VTABLE(ALCnullBackend);
  60
  61
  62 static const ALCchar nullDevice[] = "No Output";
  63
  64
  65 static void ALCnullBackend_Construct(ALCnullBackend *self, ALCdevice *device)
  66 {
  67     ALCbackend_Construct(STATIC_CAST(ALCbackend, self), device);
  68     SET_VTABLE2(ALCnullBackend, ALCbackend, self);
  69 }
  70
  71
  72 static int ALCnullBackend_mixerProc(void *ptr)
  73 {
  74     ALCnullBackend *self = (ALCnullBackend*)ptr;
  75     ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
  76     struct timespec now, start;
  77     ALuint64 avail, done;
  78     const long restTime = (long)((ALuint64)device->UpdateSize * 1000000000 /
  79                                  device->Frequency / 2);
  80
  81     SetRTPriority();
  82     althrd_setname(althrd_current(), MIXER_THREAD_NAME);
  83
  84     done = 0;
  85     if(altimespec_get(&start, AL_TIME_UTC) != AL_TIME_UTC)
  86     {
  87         ERR("Failed to get starting time\n");
  88         return 1;
  89     }
  90     while(!self->killNow && device->Connected)
  91     {
  92         if(altimespec_get(&now, AL_TIME_UTC) != AL_TIME_UTC)
  93         {
  94             ERR("Failed to get current time\n");
  95             return 1;
  96         }
  97
  98         avail  = (now.tv_sec - start.tv_sec) * device->Frequency;
  99         avail += (ALint64)(now.tv_nsec - start.tv_nsec) * device->Frequency / 1000000000;
 100         if(avail < done)
 101         {
 102             /* Oops, time skipped backwards. Reset the number of samples done
 103              * with one update available since we (likely) just came back from
 104              * sleeping. */
 105             done = avail - device->UpdateSize;
 106         }
 107
 108         if(avail-done < device->UpdateSize)
 109             al_nssleep(restTime);
 110         else while(avail-done >= device->UpdateSize)
 111         {
 112             ALCnullBackend_lock(self);
 113             aluMixData(device, NULL, device->UpdateSize);
 114             ALCnullBackend_unlock(self);
 115             done += device->UpdateSize;
 116         }
 117     }
 118
 119     return 0;
 120 }
 121
 122
 123 static ALCenum ALCnullBackend_open(ALCnullBackend *self, const ALCchar *name)
 124 {
 125     ALCdevice *device;
 126
 127     if(!name)
 128         name = nullDevice;
 129     else if(strcmp(name, nullDevice) != 0)
 130         return ALC_INVALID_VALUE;
 131
 132     device = STATIC_CAST(ALCbackend, self)->mDevice;
 133     alstr_copy_cstr(&device->DeviceName, name);
 134
 135     return ALC_NO_ERROR;
 136 }
 137
 138 static void ALCnullBackend_close(ALCnullBackend* UNUSED(self))
 139 {
 140 }
 141
 142 static ALCboolean ALCnullBackend_reset(ALCnullBackend *self)
 143 {
 144     SetDefaultWFXChannelOrder(STATIC_CAST(ALCbackend, self)->mDevice);
 145     return ALC_TRUE;
 146 }
 147
 148 static ALCboolean ALCnullBackend_start(ALCnullBackend *self)
 149 {
 150     self->killNow = 0;
 151     if(althrd_create(&self->thread, ALCnullBackend_mixerProc, self) != althrd_success)
 152         return ALC_FALSE;
 153     return ALC_TRUE;
 154 }
 155
 156 static void ALCnullBackend_stop(ALCnullBackend *self)
 157 {
 158     int res;
 159
 160     if(self->killNow)
 161         return;
 162
 163     self->killNow = 1;
 164     althrd_join(self->thread, &res);
 165 }
 166
 167
 168 typedef struct ALCnullBackendFactory {
 169     DERIVE_FROM_TYPE(ALCbackendFactory);
 170 } ALCnullBackendFactory;
 171 #define ALCNULLBACKENDFACTORY_INITIALIZER { { GET_VTABLE2(ALCnullBackendFactory, ALCbackendFactory) } }
 172
 173 ALCbackendFactory *ALCnullBackendFactory_getFactory(void);
 174
 175 static ALCboolean ALCnullBackendFactory_init(ALCnullBackendFactory *self);
 176 static DECLARE_FORWARD(ALCnullBackendFactory, ALCbackendFactory, void, deinit)
 177 static ALCboolean ALCnullBackendFactory_querySupport(ALCnullBackendFactory *self, ALCbackend_Type type);
 178 static void ALCnullBackendFactory_probe(ALCnullBackendFactory *self, enum DevProbe type);
 179 static ALCbackend* ALCnullBackendFactory_createBackend(ALCnullBackendFactory *self, ALCdevice *device, ALCbackend_Type type);
 180 DEFINE_ALCBACKENDFACTORY_VTABLE(ALCnullBackendFactory);
 181
 182
 183 ALCbackendFactory *ALCnullBackendFactory_getFactory(void)
 184 {
 185     static ALCnullBackendFactory factory = ALCNULLBACKENDFACTORY_INITIALIZER;
 186     return STATIC_CAST(ALCbackendFactory, &factory);
 187 }
 188
 189
 190 static ALCboolean ALCnullBackendFactory_init(ALCnullBackendFactory* UNUSED(self))
 191 {
 192     return ALC_TRUE;
 193 }
 194
 195 static ALCboolean ALCnullBackendFactory_querySupport(ALCnullBackendFactory* UNUSED(self), ALCbackend_Type type)
 196 {
 197     if(type == ALCbackend_Playback)
 198         return ALC_TRUE;
 199     return ALC_FALSE;
 200 }
 201
 202 static void ALCnullBackendFactory_probe(ALCnullBackendFactory* UNUSED(self), enum DevProbe type)
 203 {
 204     switch(type)
 205     {
 206         case ALL_DEVICE_PROBE:
 207             AppendAllDevicesList(nullDevice);
 208             break;
 209         case CAPTURE_DEVICE_PROBE:
 210             break;
 211     }
 212 }
 213
 214 static ALCbackend* ALCnullBackendFactory_createBackend(ALCnullBackendFactory* UNUSED(self), ALCdevice *device, ALCbackend_Type type)
 215 {
 216     if(type == ALCbackend_Playback)
 217     {
 218         ALCnullBackend *backend;
 219         NEW_OBJ(backend, ALCnullBackend)(device);
 220         if(!backend) return NULL;
 221         return STATIC_CAST(ALCbackend, backend);
 222     }
 223
 224     return NULL;
 225 }