Source/modules/webmidi/MIDIInput.cpp

/*
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#include "config.h"
#include "modules/webmidi/MIDIInput.h"

#include "modules/webmidi/MIDIAccess.h"
#include "modules/webmidi/MIDIMessageEvent.h"

namespace WebCore {

PassRefPtr<MIDIInput> MIDIInput::create(MIDIAccess* access, ExecutionContext* context, const String& id, const String& manufacturer, const String& name, const String& version)
{
    ASSERT(access);
    RefPtr<MIDIInput> input = adoptRef(new MIDIInput(access, context, id, manufacturer, name, version));
    input->suspendIfNeeded();
    return input.release();
}

MIDIInput::MIDIInput(MIDIAccess* access, ExecutionContext* context, const String& id, const String& manufacturer, const String& name, const String& version)
    : MIDIPort(context, id, manufacturer, name, MIDIPortTypeInput, version)
    , m_access(access)
{
    ScriptWrappable::init(this);
}

void MIDIInput::didReceiveMIDIData(unsigned portIndex, const unsigned char* data, size_t length, double timeStamp)
{
    ASSERT(isMainThread());

    // The received MIDI data may contain one or more messages.
    // The Web MIDI API requires that a separate event be dispatched for each message,
    // so we walk through the data and dispatch one at a time.
    size_t i = 0;
    while (i < length) {
        unsigned char status = data[i];
        unsigned char strippedStatus = status & 0xf0;

        // FIXME: integrate sending side filtering and implement more extensive filtering.
        if (strippedStatus >= 0xf0 && !m_access->sysExEnabled())
            break;

        // All non System Exclusive messages have a total size of 3 except for Program Change and Channel Pressure.
        size_t totalMessageSize = (strippedStatus == 0xc0 || strippedStatus == 0xd0) ? 2 : 3;

        if (i + totalMessageSize <= length) {
            RefPtr<Uint8Array> array = Uint8Array::create(totalMessageSize);
            array->setRange(data + i, totalMessageSize, 0);

            dispatchEvent(MIDIMessageEvent::create(timeStamp, array));
        }

        i += totalMessageSize;
    }
}

} // namespace WebCore