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https://github.com/scratchfoundation/scratch-audio.git
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Update to use ES6 class syntax
This commit is contained in:
Ray Schamp
parent
5007c43ddf
commit
9874cf006f
13 changed files with 1011 additions and 1026 deletions
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@ -1,107 +1,109 @@
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/**
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* ArrayBufferStream wraps the built-in javascript ArrayBuffer, adding the ability to access
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* data in it like a stream, tracking its position.
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* You can request to read a value from the front of the array, and it will keep track of the position
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* within the byte array, so that successive reads are consecutive.
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* The available types to read include:
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* Uint8, Uint8String, Int16, Uint16, Int32, Uint32
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* @param {ArrayBuffer} arrayBuffer - array to use as a stream
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* @constructor
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*/
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const ArrayBufferStream = function (arrayBuffer) {
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this.arrayBuffer = arrayBuffer;
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this.position = 0;
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};
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/**
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* Return a new ArrayBufferStream that is a slice of the existing one
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* @param {number} length - the number of bytes of extract
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* @return {ArrayBufferStream} the extracted stream
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*/
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ArrayBufferStream.prototype.extract = function (length) {
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const slicedArrayBuffer = this.arrayBuffer.slice(this.position, this.position + length);
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const newStream = new ArrayBufferStream(slicedArrayBuffer);
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return newStream;
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};
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/**
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* @return {number} the length of the stream in bytes
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*/
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ArrayBufferStream.prototype.getLength = function () {
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return this.arrayBuffer.byteLength;
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};
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/**
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* @return {number} the number of bytes available after the current position in the stream
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*/
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ArrayBufferStream.prototype.getBytesAvailable = function () {
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return (this.arrayBuffer.byteLength - this.position);
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};
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/**
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* Read an unsigned 8 bit integer from the stream
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* @return {number} the next 8 bit integer in the stream
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*/
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ArrayBufferStream.prototype.readUint8 = function () {
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const val = new Uint8Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 1;
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return val;
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};
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/**
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* Read a sequence of bytes of the given length and convert to a string.
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* This is a convenience method for use with short strings.
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* @param {number} length - the number of bytes to convert
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* @return {string} a String made by concatenating the chars in the input
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*/
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ArrayBufferStream.prototype.readUint8String = function (length) {
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const arr = new Uint8Array(this.arrayBuffer, this.position, length);
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this.position += length;
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let str = '';
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for (let i = 0; i < arr.length; i++) {
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str += String.fromCharCode(arr[i]);
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class ArrayBufferStream {
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/**
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* ArrayBufferStream wraps the built-in javascript ArrayBuffer, adding the ability to access
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* data in it like a stream, tracking its position.
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* You can request to read a value from the front of the array, and it will keep track of the position
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* within the byte array, so that successive reads are consecutive.
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* The available types to read include:
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* Uint8, Uint8String, Int16, Uint16, Int32, Uint32
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* @param {ArrayBuffer} arrayBuffer - array to use as a stream
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* @constructor
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*/
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constructor (arrayBuffer) {
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this.arrayBuffer = arrayBuffer;
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this.position = 0;
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}
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return str;
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};
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/**
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* Read a 16 bit integer from the stream
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* @return {number} the next 16 bit integer in the stream
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*/
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ArrayBufferStream.prototype.readInt16 = function () {
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const val = new Int16Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 2; // one 16 bit int is 2 bytes
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return val;
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};
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/**
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* Return a new ArrayBufferStream that is a slice of the existing one
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* @param {number} length - the number of bytes of extract
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* @return {ArrayBufferStream} the extracted stream
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*/
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extract (length) {
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const slicedArrayBuffer = this.arrayBuffer.slice(this.position, this.position + length);
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const newStream = new ArrayBufferStream(slicedArrayBuffer);
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return newStream;
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}
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/**
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* Read an unsigned 16 bit integer from the stream
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* @return {number} the next unsigned 16 bit integer in the stream
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*/
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ArrayBufferStream.prototype.readUint16 = function () {
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const val = new Uint16Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 2; // one 16 bit int is 2 bytes
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return val;
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};
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/**
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* @return {number} the length of the stream in bytes
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*/
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getLength () {
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return this.arrayBuffer.byteLength;
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}
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/**
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* Read a 32 bit integer from the stream
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* @return {number} the next 32 bit integer in the stream
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*/
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ArrayBufferStream.prototype.readInt32 = function () {
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const val = new Int32Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 4; // one 32 bit int is 4 bytes
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return val;
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};
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/**
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* @return {number} the number of bytes available after the current position in the stream
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*/
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getBytesAvailable () {
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return (this.arrayBuffer.byteLength - this.position);
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}
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/**
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* Read an unsigned 32 bit integer from the stream
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* @return {number} the next unsigned 32 bit integer in the stream
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*/
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ArrayBufferStream.prototype.readUint32 = function () {
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const val = new Uint32Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 4; // one 32 bit int is 4 bytes
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return val;
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};
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/**
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* Read an unsigned 8 bit integer from the stream
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* @return {number} the next 8 bit integer in the stream
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*/
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readUint8 () {
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const val = new Uint8Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 1;
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return val;
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}
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/**
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* Read a sequence of bytes of the given length and convert to a string.
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* This is a convenience method for use with short strings.
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* @param {number} length - the number of bytes to convert
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* @return {string} a String made by concatenating the chars in the input
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*/
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readUint8String (length) {
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const arr = new Uint8Array(this.arrayBuffer, this.position, length);
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this.position += length;
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let str = '';
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for (let i = 0; i < arr.length; i++) {
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str += String.fromCharCode(arr[i]);
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}
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return str;
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}
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/**
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* Read a 16 bit integer from the stream
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* @return {number} the next 16 bit integer in the stream
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*/
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readInt16 () {
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const val = new Int16Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 2; // one 16 bit int is 2 bytes
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return val;
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}
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/**
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* Read an unsigned 16 bit integer from the stream
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* @return {number} the next unsigned 16 bit integer in the stream
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*/
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readUint16 () {
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const val = new Uint16Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 2; // one 16 bit int is 2 bytes
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return val;
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}
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/**
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* Read a 32 bit integer from the stream
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* @return {number} the next 32 bit integer in the stream
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*/
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readInt32 () {
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const val = new Int32Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 4; // one 32 bit int is 4 bytes
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return val;
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}
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/**
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* Read an unsigned 32 bit integer from the stream
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* @return {number} the next unsigned 32 bit integer in the stream
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*/
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readUint32 () {
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const val = new Uint32Array(this.arrayBuffer, this.position, 1)[0];
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this.position += 4; // one 32 bit int is 4 bytes
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return val;
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}
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}
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module.exports = ArrayBufferStream;
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