delay.h

/*
 * Copyright © 2015-2023 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 "dsp/convolution/impulse_response_processor.h"
#include "dsp/delay/delay_buffer.h"
#include "model/sync.h"
 
#include <cstdint>
#include <span>
 
class Delay {
public:
    struct State {
        bool doDelay;
        int32_t userDelayRate;
        int32_t delayFeedbackAmount;
        int32_t analog_saturation = 8;
    };
 
    Delay() = default;
    Delay(const Delay& other) = delete;
 
    // was originally cloneFrom
    Delay& operator=(const Delay& rhs) {
        pingPong = rhs.pingPong;
        analog = rhs.analog;
        syncLevel = rhs.syncLevel;
        return *this;
    }
 
    [[nodiscard]] constexpr bool isActive() const { return (primaryBuffer.isActive() || secondaryBuffer.isActive()); }
 
    void informWhetherActive(bool newActive, int32_t userDelayRate = 0);
    void copySecondaryToPrimary();
    void copyPrimaryToSecondary();
    void initializeSecondaryBuffer(int32_t newNativeRate, bool makeNativeRatePreciseRelativeToOtherBuffer);
    void setupWorkingState(State& workingState, uint32_t timePerInternalTickInverse, bool anySoundComingIn = true);
    void discardBuffers();
    void setTimeToAbandon(const State& workingState);
    void hasWrapped();
 
    DelayBuffer primaryBuffer;
    DelayBuffer secondaryBuffer;
    ImpulseResponseProcessor ir_processor;
 
    uint32_t countCyclesWithoutChange;
    int32_t userRateLastTime;
    bool pingPong = true;
    bool analog = false;
 
    SyncType syncType = SYNC_TYPE_EVEN;
 
    // Basically, 0 is off, max value is 9. Higher numbers are shorter intervals (higher speed).
    SyncLevel syncLevel = SYNC_LEVEL_16TH;
 
    int32_t sizeLeftUntilBufferSwap;
 
    int32_t postLPFL;
    int32_t postLPFR;
 
    int32_t prevFeedback = 0;
 
    uint8_t repeatsUntilAbandon = 0; // 0 means never abandon
 
    void process(std::span<StereoSample> buffer, const State& delayWorkingState);
 
private:
    void prepareToBeginWriting();
    [[nodiscard]] constexpr int32_t getAmountToWriteBeforeReadingBegins() const { return secondaryBuffer.size(); }
};