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