AudioUnitUtils.h

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/*!********************************************************************
 
  Audacity: A Digital Audio Editor
 
  @file AudioUnitUtils.h
 
  Paul Licameli
 
***********************************************************************/
 
#ifndef __AUDACITY_AUDIO_UNIT_UTILS__
#define __AUDACITY_AUDIO_UNIT_UTILS__
 
#include <algorithm>
#include <AudioUnit/AudioUnit.h>
#include "CFResources.h"
#include "PackedArray.h"
 
template<typename T, OSStatus(*fn)(T*)> struct AudioUnitCleaner {
   // Let this have non-void return type, though ~unique_ptr() will ignore it
   auto operator () (T *p) noexcept { return fn(p); }
};
template<typename Ptr, OSStatus(*fn)(Ptr),
   typename T = std::remove_pointer_t<Ptr> /* deduced */ >
using AudioUnitCleanup = std::unique_ptr<T, AudioUnitCleaner<T, fn>>;
 
namespace AudioUnitUtils {
   OSStatus GetFixedSizePropertyPtr(AudioUnit unit, AudioUnitPropertyID inID,
      void *pProperty, UInt32 size, AudioUnitScope inScope,
      AudioUnitElement inElement);
 
   template<typename T>
   OSStatus GetFixedSizeProperty(AudioUnit unit, AudioUnitPropertyID inID,
      T &property,
      AudioUnitScope inScope = kAudioUnitScope_Global,
      AudioUnitElement inElement = 0)
   {
      return GetFixedSizePropertyPtr(unit, inID,
         &property, sizeof(property), inScope, inElement);
   }
 
 
   OSStatus GetVariableSizePropertyPtr(AudioUnit unit, AudioUnitPropertyID inID,
      size_t minSize, void *&pObject, size_t &size,
      AudioUnitScope inScope, AudioUnitElement inElement);
 
   template<typename T>
   OSStatus GetVariableSizeProperty(AudioUnit unit, AudioUnitPropertyID inID,
      PackedArray::Ptr<T> &pObject,
      AudioUnitScope inScope = kAudioUnitScope_Global,
      AudioUnitElement inElement = 0)
   {
      void *p{};
      size_t size{};
      auto result = GetVariableSizePropertyPtr(unit, inID,
         sizeof(typename PackedArray::Traits<T>::header_type), p, size,
         inScope, inElement);
      if (!result)
         // Construct PackedArray::Ptr
         pObject = {
            static_cast<T*>(p), // the pointer
            size // the size that the deleter must remember
         };
      return result;
   }
 
   OSStatus SetPropertyPtr(AudioUnit unit, AudioUnitPropertyID inID,
      const void *pProperty, UInt32 size, AudioUnitScope inScope,
      AudioUnitElement inElement);
 
   template<typename T>
   OSStatus SetProperty(AudioUnit unit, AudioUnitPropertyID inID,
      const T &property,
      AudioUnitScope inScope = kAudioUnitScope_Global,
      AudioUnitElement inElement = 0)
   {
      return SetPropertyPtr(unit, inID,
         &property, sizeof(property), inScope, inElement);
   }
 
 
   struct Buffer : AudioBuffer {
      Buffer(UInt32 numberChannels, UInt32 dataByteSize, void *data)
      : AudioBuffer{} {
         mNumberChannels = numberChannels;
         mDataByteSize = dataByteSize;
         mData = data;
      }
   };
 
   struct RenderCallback : AURenderCallbackStruct {
      RenderCallback(AURenderCallback inProc, void *inProcRefCon)
      : AURenderCallbackStruct{} {
         inputProc = inProc;
         inputProcRefCon = inProcRefCon;
      }
   };
 
   struct Parameter : AudioUnitParameter {
      Parameter(AudioUnit audioUnit, AudioUnitScope scope)
      : AudioUnitParameter{} {
         mAudioUnit = audioUnit;
         mScope = scope;
      }
   };
 
   struct ParameterInfo : AudioUnitParameterInfo {
      ParameterInfo() : AudioUnitParameterInfo{} {}
      ~ParameterInfo() {
         if (flags & kAudioUnitParameterFlag_CFNameRelease) {
            if (flags & kAudioUnitParameterFlag_HasCFNameString)
               if (cfNameString)
                  CFRelease(cfNameString);
            if (flags & kAudioUnitParameterUnit_CustomUnit)
               if (unitName)
                  CFRelease(unitName);
         }
      }
   };
 
   struct ParameterNameInfo : AudioUnitParameterNameInfo {
      ParameterNameInfo(AudioUnitParameterID id, SInt32 desiredLength)
      : AudioUnitParameterNameInfo{} {
         inID = id;
         inDesiredLength = desiredLength;
      }
      ~ParameterNameInfo() {
         if (outName)
            CFRelease(outName);
      }
   };
 
   struct Property : AudioUnitProperty {
      Property(AudioUnit audioUnit, AudioUnitPropertyID propertyID,
         AudioUnitScope scope)
      : AudioUnitProperty{} {
         mAudioUnit = audioUnit;
         mPropertyID = propertyID;
         mScope = scope;
         // Default element to 0
      }
   };
 
   struct UserPreset : AUPreset {
      UserPreset(CFStringRef name) : AUPreset{} {
         presetNumber = -1;
         presetName = name;
      }
   };
 
   struct StreamBasicDescription : AudioStreamBasicDescription {
      StreamBasicDescription(Float64 sampleRate,
         AudioFormatID formatID, AudioFormatFlags formatFlags,
         UInt32 bytesPerPacket, UInt32 framesPerPacket,
         UInt32 bytesPerFrame, UInt32 channelsPerFrame,
         UInt32 bitsPerChannel)
      : AudioStreamBasicDescription{} {
         mSampleRate = sampleRate;
         mFormatID = formatID;
         mFormatFlags = formatFlags;
         mBytesPerPacket = bytesPerPacket;
         mFramesPerPacket = framesPerPacket;
         mBytesPerFrame = bytesPerFrame;
         mChannelsPerFrame = channelsPerFrame;
         mBitsPerChannel = bitsPerChannel;
         // Just padding:
         // mReserved = 0; // But AudioStreamBasicDescription{} did that
      }
   };
 
}
 
 
template<> struct PackedArray::Traits<AudioBufferList> {
   struct header_type { UInt32 mNumberBuffers; };
   // Overlay the element type with the wrapper type
   using element_type = AudioUnitUtils::Buffer;
   static constexpr auto array_member = &AudioBufferList::mBuffers;
};
 
template<> struct PackedArray::Traits<AudioUnitCocoaViewInfo> {
   struct header_type {
      CF_ptr<CFURLRef> p1;
 
      header_type() {
         // Sanity checks against toolkit version change
         static_assert(offsetof(header_type, p1) ==
            offsetof(AudioUnitCocoaViewInfo, mCocoaAUViewBundleLocation));
      }
   };
   using element_type = CF_ptr<CFStringRef>;
   static constexpr auto array_member =
      &AudioUnitCocoaViewInfo::mCocoaAUViewClass;
};
 
 
#endif