JUCE/modules/juce_audio_basics/mpe/juce_MPEValue.cpp

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   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
{

MPEValue::MPEValue() noexcept                             {}
MPEValue::MPEValue (int value)  : normalisedValue (value) {}

//==============================================================================
MPEValue MPEValue::from7BitInt (int value) noexcept
{
    jassert (value >= 0 && value <= 127);

    auto valueAs14Bit = value <= 64 ? value << 7
                                    : int (jmap<float> (float (value - 64), 0.0f, 63.0f, 0.0f, 8191.0f)) + 8192;

    return { valueAs14Bit };
}

MPEValue MPEValue::from14BitInt (int value) noexcept
{
    jassert (value >= 0 && value <= 16383);
    return { value };
}

//==============================================================================
MPEValue MPEValue::minValue() noexcept      { return MPEValue::from7BitInt (0); }
MPEValue MPEValue::centreValue() noexcept   { return MPEValue::from7BitInt (64); }
MPEValue MPEValue::maxValue() noexcept      { return MPEValue::from7BitInt (127); }

int MPEValue::as7BitInt() const noexcept
{
    return normalisedValue >> 7;
}

int MPEValue::as14BitInt() const noexcept
{
    return normalisedValue;
}

//==============================================================================
float MPEValue::asSignedFloat() const noexcept
{
    return (normalisedValue < 8192)
           ? jmap<float> (float (normalisedValue), 0.0f, 8192.0f, -1.0f, 0.0f)
           : jmap<float> (float (normalisedValue), 8192.0f, 16383.0f, 0.0f, 1.0f);
}

float MPEValue::asUnsignedFloat() const noexcept
{
    return jmap<float> (float (normalisedValue), 0.0f, 16383.0f, 0.0f, 1.0f);
}

//==============================================================================
bool MPEValue::operator== (const MPEValue& other) const noexcept
{
    return normalisedValue == other.normalisedValue;
}

bool MPEValue::operator!= (const MPEValue& other) const noexcept
{
    return ! operator== (other);
}

//==============================================================================
//==============================================================================
#if JUCE_UNIT_TESTS

class MPEValueTests  : public UnitTest
{
public:
    MPEValueTests() : UnitTest ("MPEValue class", "MIDI/MPE") {}

    void runTest() override
    {
        beginTest ("comparison operator");
        {
            MPEValue value1 = MPEValue::from7BitInt (7);
            MPEValue value2 = MPEValue::from7BitInt (7);
            MPEValue value3 = MPEValue::from7BitInt (8);

            expect (value1 == value1);
            expect (value1 == value2);
            expect (value1 != value3);
        }

        beginTest ("special values");
        {
            expectEquals (MPEValue::minValue().as7BitInt(), 0);
            expectEquals (MPEValue::minValue().as14BitInt(), 0);

            expectEquals (MPEValue::centreValue().as7BitInt(), 64);
            expectEquals (MPEValue::centreValue().as14BitInt(), 8192);

            expectEquals (MPEValue::maxValue().as7BitInt(), 127);
            expectEquals (MPEValue::maxValue().as14BitInt(), 16383);
        }

        beginTest ("zero/minimum value");
        {
            expectValuesConsistent (MPEValue::from7BitInt (0),  0, 0, -1.0f, 0.0f);
            expectValuesConsistent (MPEValue::from14BitInt (0), 0, 0, -1.0f, 0.0f);
        }

        beginTest ("maximum value");
        {
            expectValuesConsistent (MPEValue::from7BitInt (127),    127, 16383, 1.0f, 1.0f);
            expectValuesConsistent (MPEValue::from14BitInt (16383), 127, 16383, 1.0f, 1.0f);
        }

        beginTest ("centre value");
        {
            expectValuesConsistent (MPEValue::from7BitInt (64),    64, 8192, 0.0f, 0.5f);
            expectValuesConsistent (MPEValue::from14BitInt (8192), 64, 8192, 0.0f, 0.5f);
        }

        beginTest ("value halfway between min and centre");
        {
            expectValuesConsistent (MPEValue::from7BitInt (32),    32, 4096, -0.5f, 0.25f);
            expectValuesConsistent (MPEValue::from14BitInt (4096), 32, 4096, -0.5f, 0.25f);
        }
    }

private:
    //==============================================================================
    void expectValuesConsistent (MPEValue value,
                                 int expectedValueAs7BitInt,
                                 int expectedValueAs14BitInt,
                                 float expectedValueAsSignedFloat,
                                 float expectedValueAsUnsignedFloat)
    {
        expectEquals (value.as7BitInt(), expectedValueAs7BitInt);
        expectEquals (value.as14BitInt(), expectedValueAs14BitInt);
        expectFloatWithinRelativeError (value.asSignedFloat(), expectedValueAsSignedFloat, 0.0001f);
        expectFloatWithinRelativeError (value.asUnsignedFloat(), expectedValueAsUnsignedFloat, 0.0001f);
    }

    //==============================================================================
    void expectFloatWithinRelativeError (float actualValue, float expectedValue, float maxRelativeError)
    {
        const float maxAbsoluteError = jmax (1.0f, std::abs (expectedValue)) * maxRelativeError;
        expect (std::abs (expectedValue - actualValue) < maxAbsoluteError);
    }
};

static MPEValueTests MPEValueUnitTests;

#endif // JUCE_UNIT_TESTS

} // namespace juce