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      1 /*
      2  * libjingle
      3  * Copyright 2004--2010, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "talk/sound/nullsoundsystem.h"
     29 
     30 #include "talk/base/logging.h"
     31 #include "talk/sound/sounddevicelocator.h"
     32 #include "talk/sound/soundinputstreaminterface.h"
     33 #include "talk/sound/soundoutputstreaminterface.h"
     34 
     35 namespace talk_base {
     36 
     37 class Thread;
     38 
     39 }
     40 
     41 namespace cricket {
     42 
     43 // Name used for the single device and the sound system itself.
     44 static const char kNullName[] = "null";
     45 
     46 class NullSoundDeviceLocator : public SoundDeviceLocator {
     47  public:
     48   NullSoundDeviceLocator() : SoundDeviceLocator(kNullName, kNullName) {}
     49 
     50   virtual SoundDeviceLocator *Copy() const {
     51     return new NullSoundDeviceLocator();
     52   }
     53 };
     54 
     55 class NullSoundInputStream : public SoundInputStreamInterface {
     56  public:
     57   virtual bool StartReading() {
     58     return true;
     59   }
     60 
     61   virtual bool StopReading() {
     62     return true;
     63   }
     64 
     65   virtual bool GetVolume(int *volume) {
     66     *volume = SoundSystemInterface::kMinVolume;
     67     return true;
     68   }
     69 
     70   virtual bool SetVolume(int volume) {
     71     return false;
     72   }
     73 
     74   virtual bool Close() {
     75     return true;
     76   }
     77 
     78   virtual int LatencyUsecs() {
     79     return 0;
     80   }
     81 };
     82 
     83 class NullSoundOutputStream : public SoundOutputStreamInterface {
     84  public:
     85   virtual bool EnableBufferMonitoring() {
     86     return true;
     87   }
     88 
     89   virtual bool DisableBufferMonitoring() {
     90     return true;
     91   }
     92 
     93   virtual bool WriteSamples(const void *sample_data,
     94                             size_t size) {
     95     LOG(LS_VERBOSE) << "Got " << size << " bytes of playback samples";
     96     return true;
     97   }
     98 
     99   virtual bool GetVolume(int *volume) {
    100     *volume = SoundSystemInterface::kMinVolume;
    101     return true;
    102   }
    103 
    104   virtual bool SetVolume(int volume) {
    105     return false;
    106   }
    107 
    108   virtual bool Close() {
    109     return true;
    110   }
    111 
    112   virtual int LatencyUsecs() {
    113     return 0;
    114   }
    115 };
    116 
    117 NullSoundSystem::~NullSoundSystem() {
    118 }
    119 
    120 bool NullSoundSystem::Init() {
    121   return true;
    122 }
    123 
    124 void NullSoundSystem::Terminate() {
    125   // Nothing to do.
    126 }
    127 
    128 bool NullSoundSystem::EnumeratePlaybackDevices(
    129       SoundSystemInterface::SoundDeviceLocatorList *devices) {
    130   ClearSoundDeviceLocatorList(devices);
    131   SoundDeviceLocator *device;
    132   GetDefaultPlaybackDevice(&device);
    133   devices->push_back(device);
    134   return true;
    135 }
    136 
    137 bool NullSoundSystem::EnumerateCaptureDevices(
    138       SoundSystemInterface::SoundDeviceLocatorList *devices) {
    139   ClearSoundDeviceLocatorList(devices);
    140   SoundDeviceLocator *device;
    141   GetDefaultCaptureDevice(&device);
    142   devices->push_back(device);
    143   return true;
    144 }
    145 
    146 bool NullSoundSystem::GetDefaultPlaybackDevice(
    147     SoundDeviceLocator **device) {
    148   *device = new NullSoundDeviceLocator();
    149   return true;
    150 }
    151 
    152 bool NullSoundSystem::GetDefaultCaptureDevice(
    153     SoundDeviceLocator **device) {
    154   *device = new NullSoundDeviceLocator();
    155   return true;
    156 }
    157 
    158 SoundOutputStreamInterface *NullSoundSystem::OpenPlaybackDevice(
    159       const SoundDeviceLocator *device,
    160       const OpenParams &params) {
    161   return new NullSoundOutputStream();
    162 }
    163 
    164 SoundInputStreamInterface *NullSoundSystem::OpenCaptureDevice(
    165       const SoundDeviceLocator *device,
    166       const OpenParams &params) {
    167   return new NullSoundInputStream();
    168 }
    169 
    170 const char *NullSoundSystem::GetName() const {
    171   return kNullName;
    172 }
    173 
    174 }  // namespace cricket
    175