JUCE/modules/juce_audio_basics/midi/juce_MidiBuffer.cpp

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

   This file is part of the JUCE library.
   Copyright (c) 2015 - ROLI Ltd.

   Permission is granted to use this software under the terms of either:
   a) the GPL v2 (or any later version)
   b) the Affero GPL v3

   Details of these licenses can be found at: www.gnu.org/licenses

   JUCE 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.

   ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.juce.com for more information.

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

namespace MidiBufferHelpers
{
    inline int getEventTime (const void* const d) noexcept
    {
        return readUnaligned<int32> (d);
    }

    inline uint16 getEventDataSize (const void* const d) noexcept
    {
        return readUnaligned<uint16> (static_cast<const char*> (d) + sizeof (int32));
    }

    inline uint16 getEventTotalSize (const void* const d) noexcept
    {
        return getEventDataSize (d) + sizeof (int32) + sizeof (uint16);
    }

    static int findActualEventLength (const uint8* const data, const int maxBytes) noexcept
    {
        unsigned int byte = (unsigned int) *data;
        int size = 0;

        if (byte == 0xf0 || byte == 0xf7)
        {
            const uint8* d = data + 1;

            while (d < data + maxBytes)
                if (*d++ == 0xf7)
                    break;

            size = (int) (d - data);
        }
        else if (byte == 0xff)
        {
            int n;
            const int bytesLeft = MidiMessage::readVariableLengthVal (data + 1, n);
            size = jmin (maxBytes, n + 2 + bytesLeft);
        }
        else if (byte >= 0x80)
        {
            size = jmin (maxBytes, MidiMessage::getMessageLengthFromFirstByte ((uint8) byte));
        }

        return size;
    }

    static uint8* findEventAfter (uint8* d, uint8* endData, const int samplePosition) noexcept
    {
        while (d < endData && getEventTime (d) <= samplePosition)
            d += getEventTotalSize (d);

        return d;
    }
}

//==============================================================================
MidiBuffer::MidiBuffer() noexcept {}
MidiBuffer::~MidiBuffer() {}

MidiBuffer::MidiBuffer (const MidiBuffer& other) noexcept  : data (other.data) {}

MidiBuffer& MidiBuffer::operator= (const MidiBuffer& other) noexcept
{
    data = other.data;
    return *this;
}

MidiBuffer::MidiBuffer (const MidiMessage& message) noexcept
{
    addEvent (message, 0);
}

void MidiBuffer::swapWith (MidiBuffer& other) noexcept      { data.swapWith (other.data); }
void MidiBuffer::clear() noexcept                           { data.clearQuick(); }
void MidiBuffer::ensureSize (size_t minimumNumBytes)        { data.ensureStorageAllocated ((int) minimumNumBytes); }
bool MidiBuffer::isEmpty() const noexcept                   { return data.size() == 0; }

void MidiBuffer::clear (const int startSample, const int numSamples)
{
    uint8* const start = MidiBufferHelpers::findEventAfter (data.begin(), data.end(), startSample - 1);
    uint8* const end   = MidiBufferHelpers::findEventAfter (start,        data.end(), startSample + numSamples - 1);

    data.removeRange ((int) (start - data.begin()), (int) (end - data.begin()));
}

void MidiBuffer::addEvent (const MidiMessage& m, const int sampleNumber)
{
    addEvent (m.getRawData(), m.getRawDataSize(), sampleNumber);
}

void MidiBuffer::addEvent (const void* const newData, const int maxBytes, const int sampleNumber)
{
    const int numBytes = MidiBufferHelpers::findActualEventLength (static_cast<const uint8*> (newData), maxBytes);

    if (numBytes > 0)
    {
        const size_t newItemSize = (size_t) numBytes + sizeof (int32) + sizeof (uint16);
        const int offset = (int) (MidiBufferHelpers::findEventAfter (data.begin(), data.end(), sampleNumber) - data.begin());

        data.insertMultiple (offset, 0, (int) newItemSize);

        uint8* const d = data.begin() + offset;
        writeUnaligned<int32>  (d, sampleNumber);
        writeUnaligned<uint16> (d + 4, static_cast<uint16> (numBytes));
        memcpy (d + 6, newData, (size_t) numBytes);
    }
}

void MidiBuffer::addEvents (const MidiBuffer& otherBuffer,
                            const int startSample,
                            const int numSamples,
                            const int sampleDeltaToAdd)
{
    Iterator i (otherBuffer);
    i.setNextSamplePosition (startSample);

    const uint8* eventData;
    int eventSize, position;

    while (i.getNextEvent (eventData, eventSize, position)
            && (position < startSample + numSamples || numSamples < 0))
    {
        addEvent (eventData, eventSize, position + sampleDeltaToAdd);
    }
}

int MidiBuffer::getNumEvents() const noexcept
{
    int n = 0;
    const uint8* const end = data.end();

    for (const uint8* d = data.begin(); d < end; ++n)
        d += MidiBufferHelpers::getEventTotalSize (d);

    return n;
}

int MidiBuffer::getFirstEventTime() const noexcept
{
    return data.size() > 0 ? MidiBufferHelpers::getEventTime (data.begin()) : 0;
}

int MidiBuffer::getLastEventTime() const noexcept
{
    if (data.size() == 0)
        return 0;

    const uint8* const endData = data.end();

    for (const uint8* d = data.begin();;)
    {
        const uint8* const nextOne = d + MidiBufferHelpers::getEventTotalSize (d);

        if (nextOne >= endData)
            return MidiBufferHelpers::getEventTime (d);

        d = nextOne;
    }
}

//==============================================================================
MidiBuffer::Iterator::Iterator (const MidiBuffer& b) noexcept
    : buffer (b), data (b.data.begin())
{
}

MidiBuffer::Iterator::~Iterator() noexcept
{
}

void MidiBuffer::Iterator::setNextSamplePosition (const int samplePosition) noexcept
{
    data = buffer.data.begin();
    const uint8* const dataEnd = buffer.data.end();

    while (data < dataEnd && MidiBufferHelpers::getEventTime (data) < samplePosition)
        data += MidiBufferHelpers::getEventTotalSize (data);
}

bool MidiBuffer::Iterator::getNextEvent (const uint8* &midiData, int& numBytes, int& samplePosition) noexcept
{
    if (data >= buffer.data.end())
        return false;

    samplePosition = MidiBufferHelpers::getEventTime (data);
    const int itemSize = MidiBufferHelpers::getEventDataSize (data);
    numBytes = itemSize;
    midiData = data + sizeof (int32) + sizeof (uint16);
    data += sizeof (int32) + sizeof (uint16) + (size_t) itemSize;

    return true;
}

bool MidiBuffer::Iterator::getNextEvent (MidiMessage& result, int& samplePosition) noexcept
{
    if (data >= buffer.data.end())
        return false;

    samplePosition = MidiBufferHelpers::getEventTime (data);
    const int itemSize = MidiBufferHelpers::getEventDataSize (data);
    result = MidiMessage (data + sizeof (int32) + sizeof (uint16), itemSize, samplePosition);
    data += sizeof (int32) + sizeof (uint16) + (size_t) itemSize;

    return true;
}