MIDI.cpp

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#include "MIDI.h"

// -----------------------------------------------------------------------------

BEGIN_MIDI_NAMESPACE

unsigned encodeSysEx(const byte* inData, byte* outSysEx, unsigned inLength)
{
    unsigned outLength  = 0;     // Num bytes in output array.
    byte count          = 0;     // Num 7bytes in a block.
    outSysEx[0]         = 0;

    for (unsigned i = 0; i < inLength; ++i)
    {
        const byte data = inData[i];
        const byte msb  = data >> 7;
        const byte body = data & 0x7f;

        outSysEx[0] |= (msb << (6 - count));
        outSysEx[1 + count] = body;

        if (count++ == 6)
        {
            outSysEx   += 8;
            outLength  += 8;
            outSysEx[0] = 0;
            count       = 0;
        }
    }
    return outLength + count + (count != 0 ? 1 : 0);
}

unsigned decodeSysEx(const byte* inSysEx, byte* outData, unsigned inLength)
{
    unsigned count  = 0;
    byte msbStorage = 0;
    byte byteIndex  = 0;

    for (unsigned i = 0; i < inLength; ++i)
    {
        if ((i % 8) == 0)
        {
            msbStorage = inSysEx[i];
            byteIndex  = 6;
        }
        else
        {
            const byte body = inSysEx[i];
            const byte msb  = ((msbStorage >> byteIndex--) & 1) << 7;
            outData[count++] = msb | body;
        }
    }
    return count;
}

END_MIDI_NAMESPACE