juce_AbstractFifo.h

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/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
//==============================================================================
class JUCE_API  AbstractFifo
{
public:
    //==============================================================================
    AbstractFifo (int capacity) noexcept;
 
    //==============================================================================
    int getTotalSize() const noexcept;

    int getFreeSpace() const noexcept;

    int getNumReady() const noexcept;

    void reset() noexcept;

    void setTotalSize (int newSize) noexcept;
 
    //==============================================================================
    void prepareToWrite (int numToWrite, int& startIndex1, int& blockSize1, int& startIndex2, int& blockSize2) const noexcept;

    void finishedWrite (int numWritten) noexcept;

    void prepareToRead (int numWanted, int& startIndex1, int& blockSize1, int& startIndex2, int& blockSize2) const noexcept;

    void finishedRead (int numRead) noexcept;
 
    //==============================================================================
 
private:
    enum class ReadOrWrite
    {
        read,
        write
    };
 
public:
    template <ReadOrWrite mode>
    class ScopedReadWrite final
    {
    public:
        ScopedReadWrite() = default;

        ScopedReadWrite (AbstractFifo& f, int num) noexcept  : fifo (&f)
        {
            prepare (*fifo, num);
        }
 
        ScopedReadWrite (const ScopedReadWrite&) = delete;
        ScopedReadWrite (ScopedReadWrite&&) noexcept;
 
        ScopedReadWrite& operator= (const ScopedReadWrite&) = delete;
        ScopedReadWrite& operator= (ScopedReadWrite&&) noexcept;

        ~ScopedReadWrite() noexcept
        {
            if (fifo != nullptr)
                finish (*fifo, blockSize1 + blockSize2);
        }

        template <typename FunctionToApply>
        void forEach (FunctionToApply&& func) const
        {
            for (auto i = startIndex1, e = startIndex1 + blockSize1; i != e; ++i)  func (i);
            for (auto i = startIndex2, e = startIndex2 + blockSize2; i != e; ++i)  func (i);
        }
 
        int startIndex1, blockSize1, startIndex2, blockSize2;
 
    private:
        void prepare (AbstractFifo&, int) noexcept;
        static void finish (AbstractFifo&, int) noexcept;
        void swap (ScopedReadWrite&) noexcept;
 
        AbstractFifo* fifo = nullptr;
    };
 
    using ScopedRead  = ScopedReadWrite<ReadOrWrite::read>;
    using ScopedWrite = ScopedReadWrite<ReadOrWrite::write>;

    ScopedRead read (int numToRead) noexcept;

    ScopedWrite write (int numToWrite) noexcept;
 
private:
    //==============================================================================
    int bufferSize;
    Atomic<int> validStart, validEnd;
 
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AbstractFifo)
};
 
template <>
inline void AbstractFifo::ScopedReadWrite<AbstractFifo::ReadOrWrite::read>::finish (AbstractFifo& f, int num) noexcept
{
    f.finishedRead (num);
}
 
template <>
inline void AbstractFifo::ScopedReadWrite<AbstractFifo::ReadOrWrite::write>::finish (AbstractFifo& f, int num) noexcept
{
    f.finishedWrite (num);
}
 
template <>
inline void AbstractFifo::ScopedReadWrite<AbstractFifo::ReadOrWrite::read>::prepare (AbstractFifo& f, int num) noexcept
{
    f.prepareToRead (num, startIndex1, blockSize1, startIndex2, blockSize2);
}
 
template <>
inline void AbstractFifo::ScopedReadWrite<AbstractFifo::ReadOrWrite::write>::prepare (AbstractFifo& f, int num) noexcept
{
    f.prepareToWrite (num, startIndex1, blockSize1, startIndex2, blockSize2);
}
 
 
} // namespace juce