Make AudioParameters a class instead of a struct

media/audio/audio_util.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Software adjust volume of samples, allows each audio stream its own
 // volume without impacting master volume for chrome and other applications.
 
 // Implemented as templates to allow 8, 16 and 32 bit implementations.
 // 8 bit is unsigned and biased by 128.
 
@@ skipping 285 matching lines @@
           static_cast<int32*>(src),
           buflen / 4,
           volume);
       break;
     default:
       NOTREACHED() << "Illegal bytes per sample";
       break;
   }
 }
 
-double GetAudioHardwareSampleRate() {
+int GetAudioHardwareSampleRate() {
 #if defined(OS_MACOSX)
     // Hardware sample-rate on the Mac can be configured, so we must query.
     return AUAudioOutputStream::HardwareSampleRate();
 #elif defined(OS_WIN)
   if (!IsWASAPISupported()) {
     // Fall back to Windows Wave implementation on Windows XP or lower
     // and use 48kHz as default input sample rate.
-    return 48000.0;
+    return 48000;
   }
 
   // Hardware sample-rate on Windows can be configured, so we must query.
   // TODO(henrika): improve possibility to specify audio endpoint.
   // Use the default device (same as for Wave) for now to be compatible.
   return WASAPIAudioOutputStream::HardwareSampleRate(eConsole);
 #else
     // Hardware for Linux is nearly always 48KHz.
     // TODO(crogers) : return correct value in rare non-48KHz cases.
-    return 48000.0;
+    return 48000;
 #endif
 }
 
-double GetAudioInputHardwareSampleRate(const std::string& device_id) {
+int GetAudioInputHardwareSampleRate(const std::string& device_id) {
   // TODO(henrika): add support for device selection on all platforms.
   // Only exists on Windows today.
 #if defined(OS_MACOSX)
   return AUAudioInputStream::HardwareSampleRate();
 #elif defined(OS_WIN)
   if (!IsWASAPISupported()) {
-    return 48000.0;
+    return 48000;
   }
   return WASAPIAudioInputStream::HardwareSampleRate(device_id);
 #else
-  return 48000.0;
+  return 48000;
 #endif
 }
 
 size_t GetAudioHardwareBufferSize() {
   // The sizes here were determined by experimentation and are roughly
   // the lowest value (for low latency) that still allowed glitch-free
   // audio under high loads.
   //
   // For Mac OS X and Windows the chromium audio backend uses a low-latency
   // Core Audio API, so a low buffer size is possible. For Linux, further
   // tuning may be needed.
 #if defined(OS_MACOSX)
   return 128;
 #elif defined(OS_WIN)
   if (!IsWASAPISupported()) {
     // Fall back to Windows Wave implementation on Windows XP or lower
     // and assume 48kHz as default sample rate.
     return 2048;
   }
   // This call must be done on a COM thread configured as MTA.
   // TODO(tommi): http://code.google.com/p/chromium/issues/detail?id=103835.
   int mixing_sample_rate =
-      static_cast<int>(WASAPIAudioOutputStream::HardwareSampleRate(eConsole));
+      WASAPIAudioOutputStream::HardwareSampleRate(eConsole);
   if (mixing_sample_rate == 48000)
     return 480;
   else if (mixing_sample_rate == 44100)
     return 448;
   else
     return 960;
 #else
   return 2048;
 #endif
 }
 
-uint32 GetAudioInputHardwareChannelCount(const std::string& device_id) {
+ChannelLayout GetAudioInputHardwareChannelLayout(const std::string& device_id) {
   // TODO(henrika): add support for device selection on all platforms.
   // Only exists on Windows today.
-  enum channel_layout { MONO = 1, STEREO = 2 };
 #if defined(OS_MACOSX)
-  return MONO;
+  return CHANNEL_LAYOUT_MONO;
 #elif defined(OS_WIN)
   if (!IsWASAPISupported()) {
     // Fall back to Windows Wave implementation on Windows XP or lower and
     // use stereo by default.
-    return STEREO;
+    return CHANNEL_LAYOUT_STEREO;
   }
-  return WASAPIAudioInputStream::HardwareChannelCount(device_id);
+  return WASAPIAudioInputStream::HardwareChannelCount(device_id) == 1 ?
+      CHANNEL_LAYOUT_MONO : CHANNEL_LAYOUT_STEREO;
 #else
-  return STEREO;
+  return CHANNEL_LAYOUT_STEREO;
 #endif
 }
 
 // When transferring data in the shared memory, first word is size of data
 // in bytes. Actual data starts immediately after it.
 
 uint32 TotalSharedMemorySizeInBytes(uint32 packet_size) {
   // Need to reserve extra 4 bytes for size of data.
   return packet_size + sizeof(Atomic32);
 }
@@ skipping 44 matching lines @@
 
 bool IsWASAPISupported() {
   // Note: that function correctly returns that Windows Server 2003 does not
   // support WASAPI.
   return base::win::GetVersion() >= base::win::VERSION_VISTA;
 }
 
 #endif
 
 }  // namespace media