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file-reader-midi.html
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file-reader-midi.html
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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="file-source-string.html">
<polymer-element name="file-reader-midi">
<template></template>
<script>Polymer((function static(){
const METHODS = {
readChunk:{
value:function(){
const stream = this.reader;
const id = stream.read(4);
const length = stream.readInt32();
const data = stream.read(length);
return {
'id': id,
'length': length,
'data': data
}
}
},
readEvent:{
value:function(){
var lastEventTypeByte;
const stream = this.reader;
const event = {
deltaTime: stream.readVarInt()
};
var eventTypeByte = stream.readInt8();
if ((eventTypeByte & 0xf0) == 0xf0) {
/* system / meta event */
if (eventTypeByte == 0xff) {
/* meta event */
event.type = 'meta';
var subtypeByte = stream.readInt8();
var length = stream.readVarInt();
switch(subtypeByte) {
case 0x00:
event.subtype = 'sequenceNumber';
if (length != 2) throw "Expected length for sequenceNumber event is 2, got " + length;
event.number = stream.readInt16();
return event;
case 0x01:
event.subtype = 'text';
event.text = stream.read(length);
return event;
case 0x02:
event.subtype = 'copyrightNotice';
event.text = stream.read(length);
return event;
case 0x03:
event.subtype = 'trackName';
event.text = stream.read(length);
return event;
case 0x04:
event.subtype = 'instrumentName';
event.text = stream.read(length);
return event;
case 0x05:
event.subtype = 'lyrics';
event.text = stream.read(length);
return event;
case 0x06:
event.subtype = 'marker';
event.text = stream.read(length);
return event;
case 0x07:
event.subtype = 'cuePoint';
event.text = stream.read(length);
return event;
case 0x20:
event.subtype = 'midiChannelPrefix';
if (length != 1) throw "Expected length for midiChannelPrefix event is 1, got " + length;
event.channel = stream.readInt8();
return event;
case 0x2f:
event.subtype = 'endOfTrack';
if (length != 0) throw "Expected length for endOfTrack event is 0, got " + length;
return event;
case 0x51:
event.subtype = 'setTempo';
if (length != 3) throw "Expected length for setTempo event is 3, got " + length;
event.microsecondsPerBeat = (
(stream.readInt8() << 16)
+ (stream.readInt8() << 8)
+ stream.readInt8()
)
return event;
case 0x54:
event.subtype = 'smpteOffset';
if (length != 5) throw "Expected length for smpteOffset event is 5, got " + length;
var hourByte = stream.readInt8();
event.frameRate = {
0x00: 24, 0x20: 25, 0x40: 29, 0x60: 30
}[hourByte & 0x60];
event.hour = hourByte & 0x1f;
event.min = stream.readInt8();
event.sec = stream.readInt8();
event.frame = stream.readInt8();
event.subframe = stream.readInt8();
return event;
case 0x58:
event.subtype = 'timeSignature';
if (length != 4) throw "Expected length for timeSignature event is 4, got " + length;
event.numerator = stream.readInt8();
event.denominator = Math.pow(2, stream.readInt8());
event.metronome = stream.readInt8();
event.thirtyseconds = stream.readInt8();
return event;
case 0x59:
event.subtype = 'keySignature';
if (length != 2) throw "Expected length for keySignature event is 2, got " + length;
event.key = stream.readInt8(true);
event.scale = stream.readInt8();
return event;
case 0x7f:
event.subtype = 'sequencerSpecific';
event.data = stream.read(length);
return event;
default:
// console.log("Unrecognised meta event subtype: " + subtypeByte);
event.subtype = 'unknown'
event.data = stream.read(length);
return event;
}
event.data = stream.read(length);
return event;
} else if (eventTypeByte == 0xf0) {
event.type = 'sysEx';
var length = stream.readVarInt();
event.data = stream.read(length);
return event;
} else if (eventTypeByte == 0xf7) {
event.type = 'dividedSysEx';
var length = stream.readVarInt();
event.data = stream.read(length);
return event;
} else {
throw "Unrecognised MIDI event type byte: " + eventTypeByte;
}
} else {
/* channel event */
var param1;
if ((eventTypeByte & 0x80) == 0) {
/* running status - reuse lastEventTypeByte as the event type.
eventTypeByte is actually the first parameter
*/
param1 = eventTypeByte;
eventTypeByte = lastEventTypeByte;
} else {
param1 = stream.readInt8();
lastEventTypeByte = eventTypeByte;
}
var eventType = eventTypeByte >> 4;
event.channel = eventTypeByte & 0x0f;
event.type = 'channel';
switch (eventType) {
case 0x08:
event.subtype = 'noteOff';
event.noteNumber = param1;
event.velocity = stream.readInt8();
return event;
case 0x09:
event.noteNumber = param1;
event.velocity = stream.readInt8();
if (event.velocity == 0) {
event.subtype = 'noteOff';
} else {
event.subtype = 'noteOn';
}
return event;
case 0x0a:
event.subtype = 'noteAftertouch';
event.noteNumber = param1;
event.amount = stream.readInt8();
return event;
case 0x0b:
event.subtype = 'controller';
event.controllerType = param1;
event.value = stream.readInt8();
return event;
case 0x0c:
event.subtype = 'programChange';
event.programNumber = param1;
return event;
case 0x0d:
event.subtype = 'channelAftertouch';
event.amount = param1;
return event;
case 0x0e:
event.subtype = 'pitchBend';
event.value = param1 + (stream.readInt8() << 7);
return event;
default:
throw "Unrecognised MIDI event type: " + eventType
/*
console.log("Unrecognised MIDI event type: " + eventType);
stream.readInt8();
event.subtype = 'unknown';
return event;
*/
}
}
}
},
readFileHeader:{
value:function(data){
const stream = this.reader;
stream.source = data;
const headerChunk = this.readChunk();
if (headerChunk.id != 'MThd' || headerChunk.length != 6)
throw "Bad .mid file - header not found";
return {
"headerChunk":headerChunk,
"fileData": stream.source
}
}
},
readHeaderChunk:{
value:function(headerChunk){
const stream = this.reader;
stream.source = headerChunk.data;
const formatType = stream.readInt16();
const trackCount = stream.readInt16();
const timeDivision = stream.readInt16();
if (timeDivision & 0x8000)
throw "Expressing time division in SMTPE frames is not supported yet"
else
const ticksPerBeat = timeDivision;
return {
'formatType': formatType,
'trackCount': trackCount,
'ticksPerBeat': ticksPerBeat,
}
}
},
readTrackHeader:{
value:function(data){
const stream = this.reader;
stream.source = data;
const trackChunk = this.readChunk();
if (trackChunk.id != 'MTrk') {
throw "Unexpected chunk - expected MTrk, got "+ trackChunk.id;
}
return {
"trackChunk":trackChunk,
"fileData":stream.source
}
}
},
readTrackChunk:{
value:function(trackChunk){
const track = [];
const stream = this.reader;
stream.source = trackChunk.data;
// var trackStream = Stream(trackChunk.data);
while (!stream.eof()) {
var event = this.readEvent();
track.push(event);
//console.log(event);
}
return track;
}
},
};
const PROTOTYPE={
publish:{
rawSource:"",
file:null,
},
rawSourceChanged:function(oldV,newV) {
if(this.reader){
var reader = this.reader;
}else{
var reader = new fileSourceString();
this.reader = reader;
this.shadowRoot.appendChild(reader);
}
const fileHeader = this.readFileHeader(newV);
const header = this.readHeaderChunk(fileHeader.headerChunk);
var data = fileHeader.fileData;
const tracks = [];
for (var i = 0; i < header.trackCount; i++) {
var trackHeader = this.readTrackHeader(data);
tracks.push(this.readTrackChunk(trackHeader.trackChunk));
data = trackHeader.fileData;
}
this.file = new MIDI(header,tracks);
this.fire("file-read-complete",this.file);
function MIDI(header,tracks){
this.header = header;
this.tracks = tracks;
}
}
};
Object.defineProperties(PROTOTYPE,METHODS);
return PROTOTYPE;
})())
/*
const $define = Object.defineProperty;
function MIDI(fileFormat,numberOfTracks,deltaTime){
this.fileFormat = fileFormat;
this.numberOfTracks = numberOfTracks;
this.deltaTime = deltaTime;
}
function Track(length){
this.length = length;
}
$constants.call(MIDI.prototype,{
SINGLE_TRACK:0,
MULTIPLE_TRACKS_SYNC:1,
MULTIPLE_TRACKS_ASYNC:2
});
const FILEDEF = $define(
$null(),
$hash(0x4D,0x54,0x68,0x64),
$var(function midiHeader(f1,f2,n1,n2,d1,d2){
const INSTANCE = new MIDI(
$add(f1,f2),
$add(n1,n2),
$add(d1,d2)
);
INSTANCE.tracks = [];
$define(
this,
$hash(0x4D,0x54,0x72,0x6B),
$var(function trackChunk(L1,L2,L3,L4){
const TRACK = new Track($sum8(arguments));
INSTANCE.tracks.push(TRACK)
return INSTANCE;
})
);
//console.log(this);
//byteoffset
return INSTANCE;
}));
const PROTOTYPE = {
fileDefinition:FILEDEF
};
return PROTOTYPE;
function $sum8(){
var args
arguments.length>1?
args = [].slice.call(arguments):
args = [].slice.call(arguments[0]);
var result;
while(args.length){
result=result<<8|args.shift();
}
return result;
}
function $null(d){
return Object.create(null,d);
}
function $constants(hash){
for(key in hash)$define(this,key,$const(hash[key]));
return this;
}
function $variables(hash){
for(key in hash)$define(this,key,$var(hash[key]));
return this;
}
function $hash(array,multiple){
return String.fromCharCode.apply(null,multiple?arguments:array.length?array:[array]);
}
function $get(val){
return {get:val};
}
function $set(val){
return {set:val};
}
function $const(val){
return {value:val};
}
function $var(val){
return {enumerable:true,writable:true,configurable:true,value:val};
}
function $prop(val){
return {writable:true,configurable:true,value:val};
}
*/</script>
</polymer-element>