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, ALint64, getLatency)
  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             aluMixData(device, NULL, device->UpdateSize);
 113             done += device->UpdateSize;
 114         }
 115     }
 116
 117     return 0;
 118 }
 119
 120
 121 static ALCenum ALCnullBackend_open(ALCnullBackend *self, const ALCchar *name)
 122 {
 123     ALCdevice *device;
 124
 125     if(!name)
 126         name = nullDevice;
 127     else if(strcmp(name, nullDevice) != 0)
 128         return ALC_INVALID_VALUE;
 129
 130     device = STATIC_CAST(ALCbackend, self)->mDevice;
 131     al_string_copy_cstr(&device->DeviceName, name);
 132
 133     return ALC_NO_ERROR;
 134 }
 135
 136 static void ALCnullBackend_close(ALCnullBackend* UNUSED(self))
 137 {
 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     self->killNow = 0;
 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(self->killNow)
 159         return;
 160
 161     self->killNow = 1;
 162     althrd_join(self->thread, &res);
 163 }
 164
 165
 166 typedef struct ALCnullBackendFactory {
 167     DERIVE_FROM_TYPE(ALCbackendFactory);
 168 } ALCnullBackendFactory;
 169 #define ALCNULLBACKENDFACTORY_INITIALIZER { { GET_VTABLE2(ALCnullBackendFactory, ALCbackendFactory) } }
 170
 171 ALCbackendFactory *ALCnullBackendFactory_getFactory(void);
 172
 173 static ALCboolean ALCnullBackendFactory_init(ALCnullBackendFactory *self);
 174 static DECLARE_FORWARD(ALCnullBackendFactory, ALCbackendFactory, void, deinit)
 175 static ALCboolean ALCnullBackendFactory_querySupport(ALCnullBackendFactory *self, ALCbackend_Type type);
 176 static void ALCnullBackendFactory_probe(ALCnullBackendFactory *self, enum DevProbe type);
 177 static ALCbackend* ALCnullBackendFactory_createBackend(ALCnullBackendFactory *self, ALCdevice *device, ALCbackend_Type type);
 178 DEFINE_ALCBACKENDFACTORY_VTABLE(ALCnullBackendFactory);
 179
 180
 181 ALCbackendFactory *ALCnullBackendFactory_getFactory(void)
 182 {
 183     static ALCnullBackendFactory factory = ALCNULLBACKENDFACTORY_INITIALIZER;
 184     return STATIC_CAST(ALCbackendFactory, &factory);
 185 }
 186
 187
 188 static ALCboolean ALCnullBackendFactory_init(ALCnullBackendFactory* UNUSED(self))
 189 {
 190     return ALC_TRUE;
 191 }
 192
 193 static ALCboolean ALCnullBackendFactory_querySupport(ALCnullBackendFactory* UNUSED(self), ALCbackend_Type type)
 194 {
 195     if(type == ALCbackend_Playback)
 196         return ALC_TRUE;
 197     return ALC_FALSE;
 198 }
 199
 200 static void ALCnullBackendFactory_probe(ALCnullBackendFactory* UNUSED(self), enum DevProbe type)
 201 {
 202     switch(type)
 203     {
 204         case ALL_DEVICE_PROBE:
 205             AppendAllDevicesList(nullDevice);
 206             break;
 207         case CAPTURE_DEVICE_PROBE:
 208             break;
 209     }
 210 }
 211
 212 static ALCbackend* ALCnullBackendFactory_createBackend(ALCnullBackendFactory* UNUSED(self), ALCdevice *device, ALCbackend_Type type)
 213 {
 214     if(type == ALCbackend_Playback)
 215     {
 216         ALCnullBackend *backend;
 217
 218         backend = ALCnullBackend_New(sizeof(*backend));
 219         if(!backend) return NULL;
 220         memset(backend, 0, sizeof(*backend));
 221
 222         ALCnullBackend_Construct(backend, device);
 223
 224         return STATIC_CAST(ALCbackend, backend);
 225     }
 226
 227     return NULL;
 228 }