HOME

// Beyond this value, index getters/setters (i.e. array[0], array[1]) are so slow to
// create, and consume so much memory, that the browser appears frozen.
var MAX_ARRAY_LENGTH = 1e5;

// Approximations of internal ECMAScript conversion functions
var ECMAScript = (function () {
	// Stash a copy in case other scripts modify these
	var opts = Object.prototype.toString;
	var ophop = Object.prototype.hasOwnProperty;

	return {
		// Class returns internal [[Class]] property, used to avoid cross-frame instanceof issues:
		Class: function (v) { return opts.call(v).replace(/^\[object *|\]$/g, ''); },
		HasProperty: function (o, p) { return p in o; },
		HasOwnProperty: function (o, p) { return ophop.call(o, p); },
		IsCallable: function (o) { return typeof o === 'function'; },
		ToInt32: function (v) { return v >> 0; },
		ToUint32: function (v) { return v >>> 0; }
	};
}());

// Snapshot intrinsics
var LN2 = Math.LN2;
var abs = Math.abs;
var floor = Math.floor;
var log = Math.log;
var min = Math.min;
var pow = Math.pow;
var round = Math.round;

function clamp(v, minimum, max) { return v < minimum ? minimum : v > max ? max : v; }

var getOwnPropNames = Object.getOwnPropertyNames || function (o) {
	if (o !== Object(o)) {
		throw new TypeError('Object.getOwnPropertyNames called on non-object');
	}
	var props = [],
		p;
	for (p in o) {
		if (ECMAScript.HasOwnProperty(o, p)) {
			props.push(p);
		}
	}
	return props;
};

// emulate ES5 getter/setter API using legacy APIs
// http://blogs.msdn.com/b/ie/archive/2010/09/07/transitioning-existing-code-to-the-es5-getter-setter-apis.aspx
// (second clause tests for Object.defineProperty() in IE<9 that only supports extending DOM prototypes, but
// note that IE<9 does not support __defineGetter__ or __defineSetter__ so it just renders the method harmless)
var defineProp;
if (Object.defineProperty && (function () {
	try {
		Object.defineProperty({}, 'x', {});
		return true;
	} catch (e) {
		return false;
	}
}())) {
	defineProp = Object.defineProperty;
} else {
	defineProp = function (o, p, desc) {
		if (!o === Object(o)) {
			throw new TypeError('Object.defineProperty called on non-object');
		}
		if (ECMAScript.HasProperty(desc, 'get') && Object.prototype.__defineGetter__) {
			Object.prototype.__defineGetter__.call(o, p, desc.get);
		}
		if (ECMAScript.HasProperty(desc, 'set') && Object.prototype.__defineSetter__) {
			Object.prototype.__defineSetter__.call(o, p, desc.set);
		}
		if (ECMAScript.HasProperty(desc, 'value')) {
			o[p] = desc.value;
		}
		return o;
	};
}

// ES5: lock down object properties
function configureProperties(obj) {
	if (getOwnPropNames && defineProp) {
		var props = getOwnPropNames(obj),
			i;
		for (i = 0; i < props.length; i += 1) {
			defineProp(obj, props[i], {
				value: obj[props[i]],
				writable: false,
				enumerable: false,
				configurable: false
			});
		}
	}
}

// ES5: Make obj[index] an alias for obj._getter(index)/obj._setter(index, value)
// for index in 0 ... obj.length
function makeArrayAccessors(obj) {
	if (!defineProp) { return; }

	if (obj.length > MAX_ARRAY_LENGTH) { throw new RangeError('Array too large for polyfill'); }

	function makeArrayAccessor(index) {
		defineProp(obj, index, {
			get: function () { return obj._getter(index); },
			set: function (v) { obj._setter(index, v); },
			enumerable: true,
			configurable: false
		});
	}

	var i;
	for (i = 0; i < obj.length; i += 1) {
		makeArrayAccessor(i);
	}
}

// Internal conversion functions:
//    pack<Type>()   - take a number (interpreted as Type), output a byte array
//    unpack<Type>() - take a byte array, output a Type-like number

function as_signed(value, bits) { var s = 32 - bits; return (value << s) >> s; }
function as_unsigned(value, bits) { var s = 32 - bits; return (value << s) >>> s; }

function packI8(n) { return [n & 0xff]; }
function unpackI8(bytes) { return as_signed(bytes[0], 8); }

function packU8(n) { return [n & 0xff]; }
function unpackU8(bytes) { return as_unsigned(bytes[0], 8); }

function packU8Clamped(n) { n = round(Number(n)); return [n < 0 ? 0 : n > 0xff ? 0xff : n & 0xff]; }

function packI16(n) { return [(n >> 8) & 0xff, n & 0xff]; }
function unpackI16(bytes) { return as_signed(bytes[0] << 8 | bytes[1], 16); }

function packU16(n) { return [(n >> 8) & 0xff, n & 0xff]; }
function unpackU16(bytes) { return as_unsigned(bytes[0] << 8 | bytes[1], 16); }

function packI32(n) {
	return [
		(n >> 24) & 0xff, (n >> 16) & 0xff, (n >> 8) & 0xff, n & 0xff
	];
}
function unpackI32(bytes) { return as_signed(bytes[0] << 24 | bytes[1] << 16 | bytes[2] << 8 | bytes[3], 32); }

function packU32(n) {
	return [
		(n >> 24) & 0xff, (n >> 16) & 0xff, (n >> 8) & 0xff, n & 0xff
	];
}
function unpackU32(bytes) { return as_unsigned(bytes[0] << 24 | bytes[1] << 16 | bytes[2] << 8 | bytes[3], 32); }

function packIEEE754(v, ebits, fbits) {

	var bias = (1 << (ebits - 1)) - 1;
	var s, e, f,
		i, bits, str, bytes;

	function roundToEven(n) {
		var w = floor(n);
		var fl = n - w;
		if (fl < 0.5) { return w; }
		if (fl > 0.5) { return w + 1; }
		return w % 2 ? w + 1 : w;
	}

	// Compute sign, exponent, fraction
	if (v !== v) {
		// NaN
		// http://dev.w3.org/2006/webapi/WebIDL/#es-type-mapping
		e = (1 << ebits) - 1; f = pow(2, fbits - 1); s = 0;
	} else if (v === Infinity || v === -Infinity) {
		e = (1 << ebits) - 1; f = 0; s = v < 0 ? 1 : 0;
	} else if (v === 0) {
		e = 0; f = 0; s = 1 / v === -Infinity ? 1 : 0;
	} else {
		s = v < 0;
		v = abs(v);

		if (v >= pow(2, 1 - bias)) {
			e = min(floor(log(v) / LN2), 1023);
			f = roundToEven(v / pow(2, e) * pow(2, fbits));
			if (f / pow(2, fbits) >= 2) {
				e = e + 1;
				f = 1;
			}
			if (e > bias) {
				// Overflow
				e = (1 << ebits) - 1;
				f = 0;
			} else {
				// Normalized
				e = e + bias;
				f = f - pow(2, fbits);
			}
		} else {
			// Denormalized
			e = 0;
			f = roundToEven(v / pow(2, 1 - bias - fbits));
		}
	}

	// Pack sign, exponent, fraction
	bits = [];
	for (i = fbits; i; i -= 1) { bits.push(f % 2 ? 1 : 0); f = floor(f / 2); }
	for (i = ebits; i; i -= 1) { bits.push(e % 2 ? 1 : 0); e = floor(e / 2); }
	bits.push(s ? 1 : 0);
	bits.reverse();
	str = bits.join('');

	// Bits to bytes
	bytes = [];
	while (str.length) {
		bytes.push(parseInt(str.substring(0, 8), 2));
		str = str.substring(8);
	}
	return bytes;
}

function unpackIEEE754(bytes, ebits, fbits) {

	// Bytes to bits
	var bits = [],
		i, j, b, str,
		bias, s, e, f;

	for (i = bytes.length; i; i -= 1) {
		b = bytes[i - 1];
		for (j = 8; j; j -= 1) {
			bits.push(b % 2 ? 1 : 0); b = b >> 1;
		}
	}
	bits.reverse();
	str = bits.join('');

	// Unpack sign, exponent, fraction
	bias = (1 << (ebits - 1)) - 1;
	s = parseInt(str.substring(0, 1), 2) ? -1 : 1;
	e = parseInt(str.substring(1, 1 + ebits), 2);
	f = parseInt(str.substring(1 + ebits), 2);

	// Produce number
	if (e === (1 << ebits) - 1) {
		return f === 0 ? s * Infinity : NaN;
	} else if (e > 0) {
		// Normalized
		return s * pow(2, e - bias) * (1 + (f / pow(2, fbits)));
	} else if (f !== 0) {
		// Denormalized
		return s * pow(2, -(bias - 1)) * (f / pow(2, fbits));
	}
	return s < 0 ? -0 : 0;

}

function unpackF64(b) { return unpackIEEE754(b, 11, 52); }
function packF64(v) { return packIEEE754(v, 11, 52); }
function unpackF32(b) { return unpackIEEE754(b, 8, 23); }
function packF32(v) { return packIEEE754(v, 8, 23); }

//
// 3 The ArrayBuffer Type
//

(function () {

	/** @constructor */
	function ArrayBuffer(length) {
		length = ECMAScript.ToInt32(length);
		if (length < 0) { throw new RangeError('ArrayBuffer size is not a small enough positive integer'); }

		this.byteLength = length;
		this._bytes = [];
		this._bytes.length = length;

		var i;
		for (i = 0; i < this.byteLength; i += 1) {
			this._bytes[i] = 0;
		}

		configureProperties(this);
	}

	exports.ArrayBuffer = exports.ArrayBuffer || ArrayBuffer;

	//
	// 4 The ArrayBufferView Type
	//

	// NOTE: this constructor is not exported
	/** @constructor */
	function ArrayBufferView() {
		// this.buffer = null;
		// this.byteOffset = 0;
		// this.byteLength = 0;
	}

	//
	// 5 The Typed Array View Types
	//

	function makeConstructor(bytesPerElement, pack, unpack) {
		// Each TypedArray type requires a distinct constructor instance with
		// identical logic, which this produces.

		var ctor;
		ctor = function (buffer, byteOffset, length) {
			var array, sequence, i, s;

			if (!arguments.length || typeof arguments[0] === 'number') {
				// Constructor(unsigned long length)
				this.length = ECMAScript.ToInt32(arguments[0]);
				if (length < 0) { throw new RangeError('ArrayBufferView size is not a small enough positive integer'); }

				this.byteLength = this.length * this.BYTES_PER_ELEMENT;
				this.buffer = new ArrayBuffer(this.byteLength);
				this.byteOffset = 0;
			} else if (typeof arguments[0] === 'object' && arguments[0].constructor === ctor) {
				// Constructor(TypedArray array)
				array = arguments[0];

				this.length = array.length;
				this.byteLength = this.length * this.BYTES_PER_ELEMENT;
				this.buffer = new ArrayBuffer(this.byteLength);
				this.byteOffset = 0;

				for (i = 0; i < this.length; i += 1) {
					this._setter(i, array._getter(i));
				}
			} else if (typeof arguments[0] === 'object'
                 && !(arguments[0] instanceof ArrayBuffer || ECMAScript.Class(arguments[0]) === 'ArrayBuffer')) {
				// Constructor(sequence<type> array)
				sequence = arguments[0];

				this.length = ECMAScript.ToUint32(sequence.length);
				this.byteLength = this.length * this.BYTES_PER_ELEMENT;
				this.buffer = new ArrayBuffer(this.byteLength);
				this.byteOffset = 0;

				for (i = 0; i < this.length; i += 1) {
					s = sequence[i];
					this._setter(i, Number(s));
				}
			} else if (typeof arguments[0] === 'object'
                 && (arguments[0] instanceof ArrayBuffer || ECMAScript.Class(arguments[0]) === 'ArrayBuffer')) {
				// Constructor(ArrayBuffer buffer,
				//             optional unsigned long byteOffset, optional unsigned long length)
				this.buffer = buffer;

				this.byteOffset = ECMAScript.ToUint32(byteOffset);
				if (this.byteOffset > this.buffer.byteLength) {
					throw new RangeError('byteOffset out of range');
				}

				if (this.byteOffset % this.BYTES_PER_ELEMENT) {
					// The given byteOffset must be a multiple of the element
					// size of the specific type, otherwise an exception is raised.
					throw new RangeError('ArrayBuffer length minus the byteOffset is not a multiple of the element size.');
				}

				if (arguments.length < 3) {
					this.byteLength = this.buffer.byteLength - this.byteOffset;

					if (this.byteLength % this.BYTES_PER_ELEMENT) {
						throw new RangeError('length of buffer minus byteOffset not a multiple of the element size');
					}
					this.length = this.byteLength / this.BYTES_PER_ELEMENT;
				} else {
					this.length = ECMAScript.ToUint32(length);
					this.byteLength = this.length * this.BYTES_PER_ELEMENT;
				}

				if ((this.byteOffset + this.byteLength) > this.buffer.byteLength) {
					throw new RangeError('byteOffset and length reference an area beyond the end of the buffer');
				}
			} else {
				throw new TypeError('Unexpected argument type(s)');
			}

			this.constructor = ctor;

			configureProperties(this);
			makeArrayAccessors(this);
		};

		ctor.prototype = new ArrayBufferView();
		ctor.prototype.BYTES_PER_ELEMENT = bytesPerElement;
		ctor.prototype._pack = pack;
		ctor.prototype._unpack = unpack;
		ctor.BYTES_PER_ELEMENT = bytesPerElement;

		// getter type (unsigned long index);
		ctor.prototype._getter = function (index) {
			if (arguments.length < 1) { throw new SyntaxError('Not enough arguments'); }

			index = ECMAScript.ToUint32(index);
			if (index >= this.length) {
				return undefined;
			}

			var bytes = [];
			for (var i = 0, o = this.byteOffset + (index * this.BYTES_PER_ELEMENT);
				i < this.BYTES_PER_ELEMENT;
				i += 1, o += 1) {
				bytes.push(this.buffer._bytes[o]);
			}
			return this._unpack(bytes);
		};

		// NONSTANDARD: convenience alias for getter: type get(unsigned long index);
		ctor.prototype.get = ctor.prototype._getter;

		// setter void (unsigned long index, type value);
		ctor.prototype._setter = function (index, value) {
			if (arguments.length < 2) { throw new SyntaxError('Not enough arguments'); }

			index = ECMAScript.ToUint32(index);
			if (index < this.length) {
				var bytes = this._pack(value);
				var i;
				var o;
				for (i = 0, o = this.byteOffset + (index * this.BYTES_PER_ELEMENT);
					i < this.BYTES_PER_ELEMENT;
					i += 1, o += 1) {
					this.buffer._bytes[o] = bytes[i];
				}
			}
		};

		// void set(TypedArray array, optional unsigned long offset);
		// void set(sequence<type> array, optional unsigned long offset);
		ctor.prototype.set = function (index, value) { // eslint-disable-line no-unused-vars
			if (arguments.length < 1) { throw new SyntaxError('Not enough arguments'); }
			var array, sequence, offset, len,
				i, s, d,
				byteOffset, byteLength, tmp;

			if (typeof arguments[0] === 'object' && arguments[0].constructor === this.constructor) {
				// void set(TypedArray array, optional unsigned long offset);
				array = arguments[0];
				offset = ECMAScript.ToUint32(arguments[1]);

				if (offset + array.length > this.length) {
					throw new RangeError('Offset plus length of array is out of range');
				}

				byteOffset = this.byteOffset + (offset * this.BYTES_PER_ELEMENT);
				byteLength = array.length * this.BYTES_PER_ELEMENT;

				if (array.buffer === this.buffer) {
					tmp = [];
					for (i = 0, s = array.byteOffset; i < byteLength; i += 1, s += 1) {
						tmp[i] = array.buffer._bytes[s];
					}
					for (i = 0, d = byteOffset; i < byteLength; i += 1, d += 1) {
						this.buffer._bytes[d] = tmp[i];
					}
				} else {
					for (i = 0, s = array.byteOffset, d = byteOffset;
						i < byteLength; i += 1, s += 1, d += 1) {
						this.buffer._bytes[d] = array.buffer._bytes[s];
					}
				}
			} else if (typeof arguments[0] === 'object' && typeof arguments[0].length !== 'undefined') {
				// void set(sequence<type> array, optional unsigned long offset);
				sequence = arguments[0];
				len = ECMAScript.ToUint32(sequence.length);
				offset = ECMAScript.ToUint32(arguments[1]);

				if (offset + len > this.length) {
					throw new RangeError('Offset plus length of array is out of range');
				}

				for (i = 0; i < len; i += 1) {
					s = sequence[i];
					this._setter(offset + i, Number(s));
				}
			} else {
				throw new TypeError('Unexpected argument type(s)');
			}
		};

		// TypedArray subarray(long begin, optional long end);
		ctor.prototype.subarray = function (start, end) {

			start = ECMAScript.ToInt32(start);
			end = ECMAScript.ToInt32(end);

			if (arguments.length < 1) { start = 0; }
			if (arguments.length < 2) { end = this.length; }

			if (start < 0) { start = this.length + start; }
			if (end < 0) { end = this.length + end; }

			start = clamp(start, 0, this.length);
			end = clamp(end, 0, this.length);

			var len = end - start;
			if (len < 0) {
				len = 0;
			}

			return new this.constructor(this.buffer, this.byteOffset + (start * this.BYTES_PER_ELEMENT), len);
		};

		return ctor;
	}

	var Int8Array = makeConstructor(1, packI8, unpackI8);
	var Uint8Array = makeConstructor(1, packU8, unpackU8);
	var Uint8ClampedArray = makeConstructor(1, packU8Clamped, unpackU8);
	var Int16Array = makeConstructor(2, packI16, unpackI16);
	var Uint16Array = makeConstructor(2, packU16, unpackU16);
	var Int32Array = makeConstructor(4, packI32, unpackI32);
	var Uint32Array = makeConstructor(4, packU32, unpackU32);
	var Float32Array = makeConstructor(4, packF32, unpackF32);
	var Float64Array = makeConstructor(8, packF64, unpackF64);

	exports.Int8Array = exports.Int8Array || Int8Array;
	exports.Uint8Array = exports.Uint8Array || Uint8Array;
	exports.Uint8ClampedArray = exports.Uint8ClampedArray || Uint8ClampedArray;
	exports.Int16Array = exports.Int16Array || Int16Array;
	exports.Uint16Array = exports.Uint16Array || Uint16Array;
	exports.Int32Array = exports.Int32Array || Int32Array;
	exports.Uint32Array = exports.Uint32Array || Uint32Array;
	exports.Float32Array = exports.Float32Array || Float32Array;
	exports.Float64Array = exports.Float64Array || Float64Array;
}());

//
// 6 The DataView View Type
//

(function () {
	function r(array, index) {
		return ECMAScript.IsCallable(array.get) ? array.get(index) : array[index];
	}

	var IS_BIG_ENDIAN = (function () {
		var u16array = new exports.Uint16Array([0x1234]),
			u8array = new exports.Uint8Array(u16array.buffer);
		return r(u8array, 0) === 0x12;
	}());

	// Constructor(ArrayBuffer buffer,
	//             optional unsigned long byteOffset,
	//             optional unsigned long byteLength)
	/** @constructor */
	function DataView(buffer, byteOffset, byteLength) {
		if (arguments.length === 0) {
			buffer = new exports.ArrayBuffer(0);
		} else if (!(buffer instanceof exports.ArrayBuffer || ECMAScript.Class(buffer) === 'ArrayBuffer')) {
			throw new TypeError('TypeError');
		}

		this.buffer = buffer || new exports.ArrayBuffer(0);

		this.byteOffset = ECMAScript.ToUint32(byteOffset);
		if (this.byteOffset > this.buffer.byteLength) {
			throw new RangeError('byteOffset out of range');
		}

		if (arguments.length < 3) {
			this.byteLength = this.buffer.byteLength - this.byteOffset;
		} else {
			this.byteLength = ECMAScript.ToUint32(byteLength);
		}

		if ((this.byteOffset + this.byteLength) > this.buffer.byteLength) {
			throw new RangeError('byteOffset and length reference an area beyond the end of the buffer');
		}

		configureProperties(this);
	}

	function makeGetter(arrayType) {
		return function (byteOffset, littleEndian) {

			byteOffset = ECMAScript.ToUint32(byteOffset);

			if (byteOffset + arrayType.BYTES_PER_ELEMENT > this.byteLength) {
				throw new RangeError('Array index out of range');
			}
			byteOffset += this.byteOffset;

			var uint8Array = new exports.Uint8Array(this.buffer, byteOffset, arrayType.BYTES_PER_ELEMENT),
				bytes = [],
				i;
			for (i = 0; i < arrayType.BYTES_PER_ELEMENT; i += 1) {
				bytes.push(r(uint8Array, i));
			}

			if (Boolean(littleEndian) === Boolean(IS_BIG_ENDIAN)) {
				bytes.reverse();
			}

			return r(new arrayType(new exports.Uint8Array(bytes).buffer), 0);
		};
	}

	DataView.prototype.getUint8 = makeGetter(exports.Uint8Array);
	DataView.prototype.getInt8 = makeGetter(exports.Int8Array);
	DataView.prototype.getUint16 = makeGetter(exports.Uint16Array);
	DataView.prototype.getInt16 = makeGetter(exports.Int16Array);
	DataView.prototype.getUint32 = makeGetter(exports.Uint32Array);
	DataView.prototype.getInt32 = makeGetter(exports.Int32Array);
	DataView.prototype.getFloat32 = makeGetter(exports.Float32Array);
	DataView.prototype.getFloat64 = makeGetter(exports.Float64Array);

	function makeSetter(arrayType) {
		return function (byteOffset, value, littleEndian) {

			byteOffset = ECMAScript.ToUint32(byteOffset);
			if (byteOffset + arrayType.BYTES_PER_ELEMENT > this.byteLength) {
				throw new RangeError('Array index out of range');
			}

			// Get bytes
			var typeArray = new arrayType([value]),
				byteArray = new exports.Uint8Array(typeArray.buffer),
				bytes = [],
				i, byteView;

			for (i = 0; i < arrayType.BYTES_PER_ELEMENT; i += 1) {
				bytes.push(r(byteArray, i));
			}

			// Flip if necessary
			if (Boolean(littleEndian) === Boolean(IS_BIG_ENDIAN)) {
				bytes.reverse();
			}

			// Write them
			byteView = new exports.Uint8Array(this.buffer, byteOffset, arrayType.BYTES_PER_ELEMENT);
			byteView.set(bytes);
		};
	}

	DataView.prototype.setUint8 = makeSetter(exports.Uint8Array);
	DataView.prototype.setInt8 = makeSetter(exports.Int8Array);
	DataView.prototype.setUint16 = makeSetter(exports.Uint16Array);
	DataView.prototype.setInt16 = makeSetter(exports.Int16Array);
	DataView.prototype.setUint32 = makeSetter(exports.Uint32Array);
	DataView.prototype.setInt32 = makeSetter(exports.Int32Array);
	DataView.prototype.setFloat32 = makeSetter(exports.Float32Array);
	DataView.prototype.setFloat64 = makeSetter(exports.Float64Array);

	exports.DataView = exports.DataView || DataView;

}());