time_stretcher.h

/*
 * Copyright © 2016-2023 Synthstrom Audible Limited
 *
 * This file is part of The Synthstrom Audible Deluge Firmware.
 *
 * The Synthstrom Audible Deluge Firmware is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program.
 * If not, see <https://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "definitions_cxx.hpp"
#include "model/sample/sample_low_level_reader.h"
#include <cstdint>
 
#define BUFFER_FILLING_OFF 0
#define BUFFER_FILLING_NEWER 1
#define BUFFER_FILLING_OLDER 2
#define BUFFER_FILLING_NEITHER 3
 
class VoiceSample;
class Voice;
class VoiceSamplePlaybackGuide;
class VoiceUnisonPartSource;
class Cluster;
class Sample;
class SampleCache;
 
class [[gnu::hot]] TimeStretcher {
public:
    TimeStretcher() = default;
    bool init(Sample* sample, VoiceSample* voiceSample, SamplePlaybackGuide* guide, int64_t newSamplePosBig,
              int32_t numChannels, int32_t phaseIncrement, int32_t timeStretchRatio, int32_t playDirection,
              int32_t priorityRating, int32_t fudgingNumSamplesTilLoop, LoopType loopingType);
    void reInit(int64_t newSamplePosBig, SamplePlaybackGuide* guide, VoiceSample* voiceSample, Sample* sample,
                int32_t numChannels, int32_t timeStretchRatio, int32_t phaseIncrement, uint64_t combinedIncrement,
                int32_t playDirection, LoopType loopingType, int32_t priorityRating);
    void beenUnassigned();
    void unassignAllReasonsForPercLookahead();
    void unassignAllReasonsForPercCacheClusters();
    bool hopEnd(SamplePlaybackGuide* guide, VoiceSample* voiceSample, Sample* sample, int32_t numChannels,
                int32_t timeStretchRatio, int32_t phaseIncrement, uint64_t combinedIncrement, int32_t playDirection,
                LoopType loopingType, int32_t priorityRating);
 
    void rememberPercCacheCluster(Cluster* cluster);
    void updateClustersForPercLookahead(Sample* sample, uint32_t sourceBytePos, int32_t playDirection);
 
    int32_t getSamplePos(int32_t playDirection);
    bool allocateBuffer(int32_t numChannels);
 
    void readFromBuffer(int32_t* oscBufferPos, int32_t numSamples, int32_t numChannels,
                        int32_t numChannelsAfterCondensing, int32_t sourceAmplitudeNow, int32_t amplitudeIncrementNow,
                        int32_t* bufferReadPos);
 
    void setupCrossfadeFromCache(SampleCache* cache, int32_t cacheBytePos, int32_t numChannels);
 
#if TIME_STRETCH_ENABLE_BUFFER
    void reassessWhetherToBeFillingBuffer(int32_t phaseIncrement, int32_t timeStretchRatio,
                                          int32_t newBufferFillingMode, int32_t numChannels);
#endif
 
    int64_t samplePosBig; // In whole samples including both channels. From audioDataStart. <<'d by 24
 
    uint32_t crossfadeProgress; // Out of kMaxSampleValue
    uint32_t crossfadeIncrement;
 
    int32_t samplesTilHopEnd;
 
    SampleLowLevelReader olderPartReader;
 
    int32_t* buffer;
    bool olderHeadReadingFromBuffer;
    bool hasLoopedBackIntoPreMargin;
    bool playHeadStillActive[2];
    uint8_t numTimesMissedHop;
 
    int32_t olderBufferReadPos; // In whole samples including both channels
 
#if TIME_STRETCH_ENABLE_BUFFER
    bool newerHeadReadingFromBuffer;
    int32_t newerBufferReadPos; // In whole samples including both channels
 
    uint8_t bufferFillingMode;
    int32_t bufferWritePos;        // In whole samples including both channels
    uint64_t bufferSamplesWritten; // Hopefully we can do away with the need for this
#endif
 
    Cluster* clustersForPercLookahead[kNumClustersLoadedAhead];
 
    Cluster* percCacheClustersNearby[2]; // Remembers and acts as a "reason" for the two most recently needed / accessed
                                         // Clusters, basically
 
private:
    bool setupNewPlayHead(Sample* sample, VoiceSample* voiceSample, SamplePlaybackGuide* guide, int32_t newHeadBytePos,
                          int32_t additionalOscPos, int32_t priorityRating, LoopType loopingType);
};
 
inline int32_t getTotalDifferenceAbs(int32_t* totals1, int32_t* totals2) {
    int32_t totalDifferenceAbs = 0;
    for (int32_t i = 0; i < TimeStretch::Crossfade::kNumMovingAverages; i++) {
        int32_t differenceAbsHere = totals2[i] - totals1[i];
        if (differenceAbsHere < 0)
            differenceAbsHere = -differenceAbsHere;
        totalDifferenceAbs += differenceAbsHere;
    }
    return totalDifferenceAbs;
}
 
inline int32_t getTotalChange(int32_t* totals1, int32_t* totals2) {
    int32_t totalChange = 0;
    for (int32_t i = 0; i < TimeStretch::Crossfade::kNumMovingAverages; i++) {
        totalChange += totals2[i];
    }
 
    for (int32_t i = 0; i < TimeStretch::Crossfade::kNumMovingAverages; i++) {
        totalChange -= totals1[i];
    }
    return totalChange;
}