WaveDataCache.h

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/*  SPDX-License-Identifier: GPL-2.0-or-later */
/*!********************************************************************
 
  Audacity: A Digital Audio Editor
 
  WaveDataCache.h
 
  Dmitry Vedenko
 
**********************************************************************/
#pragma once
 
#include <array>
#include <cstdint>
#include <numeric>
#include <vector>
#include <functional>
 
#include "GraphicsDataCache.h"
#include "WaveData.h"
#include "Observer.h"
 
class WaveClip;
 
struct WAVE_TRACK_PAINT_API WaveCacheSampleBlock final
{
   enum class Type
   {
      Samples,
      MinMaxRMS256,
      MinMaxRMS64k,
   };
 
   struct Summary final
   {
      size_t SamplesCount { 0 };
 
      float Min { std::numeric_limits<float>::infinity() };
      float Max { -std::numeric_limits<float>::infinity() };
 
      double SquaresSum { 0.0f };
 
      size_t SumItemsCount { 0 };
   };
 
   Type DataType { Type::Samples };
   int64_t FirstSample { 0 };
   size_t NumSamples { 0 };
 
   bool ContainsSample(int64_t sampleIndex) const noexcept;
 
   float* GetWritePointer(size_t floatsCount);
 
   void Reset() noexcept;
private:
   Summary GetSummary(
      int64_t from, size_t samplesCount,
      const Summary& initializer) const noexcept;
 
   std::vector<float> mData;
 
   friend class WaveDataCache;
};
 
struct WAVE_TRACK_PAINT_API WaveCacheElement final : GraphicsDataCacheElementBase
{
   using Columns =
      std::array<WaveDisplayColumn, GraphicsDataCacheBase::CacheElementWidth>;
 
   Columns Data;
   size_t AvailableColumns { 0 };
 
   void Smooth(GraphicsDataCacheElementBase* prevElement) override;
};
 
class WAVE_TRACK_PAINT_API WaveDataCache final :
    public GraphicsDataCache<WaveCacheElement>
{
public:
   using DataProvider = std::function<bool (int64_t requiredSample, WaveCacheSampleBlock::Type dataType, WaveCacheSampleBlock& block)>;
 
   WaveDataCache(const WaveClip& waveClip, int channelIndex);
 
private:
   bool InitializeElement(
      const GraphicsDataCacheKey& key, WaveCacheElement& element) override;
 
   DataProvider mProvider;
 
   WaveCacheSampleBlock mCachedBlock;
 
   const WaveClip& mWaveClip;
   Observer::Subscription mStretchChangedSubscription;
};