juce_SingleThreadedAbstractFifo.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 SingleThreadedAbstractFifo
{
public:
    SingleThreadedAbstractFifo() = default;

    explicit SingleThreadedAbstractFifo (int sizeIn)
        : size (sizeIn)
    {
        // This class only works properly when the size is a power of two.
        // Use nextPowerOfTwo() to find a good size, and ensure that your
        // backing storage is the same size.
        jassert (isPowerOfTwo (sizeIn));
    }

    int getRemainingSpace() const   { return size - numReadable; }

    int getNumReadable() const      { return numReadable; }

    int getSize() const             { return size; }

    std::array<Range<int>, 2> write (int num)
    {
        const auto startPos = (readPos + numReadable) & (size - 1);
        const auto maxToWrite = jmin (getRemainingSpace(), num);
        const auto firstBlockSize = jmin (maxToWrite, size - startPos);
 
        numReadable += maxToWrite;
 
        return { { { startPos, startPos + firstBlockSize }, { 0, maxToWrite - firstBlockSize } } };
    }

    std::array<Range<int>, 2> read (int num)
    {
        const auto startPos = readPos;
        const auto maxToRead = jmin (numReadable, num);
        const auto firstBlockSize = jmin (maxToRead, size - startPos);
 
        readPos = (startPos + maxToRead) & (size - 1);
        numReadable -= maxToRead;
 
        return { { { startPos, startPos + firstBlockSize }, { 0, maxToRead - firstBlockSize } } };
    }
 
private:
    int size = 0, readPos = 0, numReadable = 0;
};
 
 
} // namespace juce