function parse(buffer) {
let reader = new BufferReader(buffer);
let file = {
header: undefined,
tracks: []
};
let chunk = _readChunk(reader);
if (chunk.isHeader) {
file.header = chunk;
delete chunk.isHeader;
}
if (_.isUndefined(file.header)) {
throw new Error('MIDI file has no header data.');
}
for (let i = 0, len = file.header.numberOfTracks; i < len; i++) {
file.tracks.push(_readChunk(reader));
}
if (reader.tell() < buffer.byteLength) {
debug('File has bytes left over. This should not happen. Bytes are: ', reader.restAll());
}
return new MIDIFile(file);
}
function _readTrackChunk(reader) {
let length = reader.nextUInt32BE();
let events = [];
let initialPosition = reader.tell();
let runningStatus;
let chunkBuffer = reader.nextBuffer(length);
let chunkReader = new BufferReader(chunkBuffer);
while (chunkReader.tell() < length) {
let eventChunk = _readEvent(chunkReader, runningStatus);
runningStatus = eventChunk.runningStatus;
delete eventChunk.runningStatus;
events.push(eventChunk);
}
if (chunkReader.tell() < length) {
// there are still bytes left unread--something has gone wrong
let err = new Error('Chunk buffer was not exhausted; ' + (length - chunkReader.tell()) + ' bytes left');
err.remainingBytes = chunkReader.restAll();
throw err;
}
return events;
}