b38dea0597
Share Gaia assets and adapters, keep private profiles and development documents local, and update both public READMEs.
301 lines
No EOL
11 KiB
JavaScript
301 lines
No EOL
11 KiB
JavaScript
var BlobView = function () {
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function fail(msg) {
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throw Error(msg);
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}
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var decoderCache = {};
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function getDecoder(encoding) {
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if (encoding in decoderCache) {
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return decoderCache[encoding];
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}
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var decoder = decoderCache[encoding] = new TextDecoder(encoding);
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return decoder;
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}
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function BlobView(blob, sliceOffset, sliceLength, slice, viewOffset, viewLength, littleEndian) {
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this.blob = blob;
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this.sliceOffset = sliceOffset;
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this.sliceLength = sliceLength;
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this.slice = slice;
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this.viewOffset = viewOffset;
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this.viewLength = viewLength;
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this.littleEndian = littleEndian;
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this.view = new DataView(slice, viewOffset, viewLength);
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this.buffer = slice;
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this.byteLength = viewLength;
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this.byteOffset = viewOffset;
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this.index = 0;
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}
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BlobView.get = function (blob, offset, length, callback, littleEndian) {
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if (offset < 0) {
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fail('negative offset');
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}
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if (length < 0) {
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fail('negative length');
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}
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if (offset > blob.size) {
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fail('offset larger than blob size');
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}
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if (offset + length > blob.size) {
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length = blob.size - offset;
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}
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var slice = blob.slice(offset, offset + length);
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var reader = new FileReader();
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reader.readAsArrayBuffer(slice);
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reader.onloadend = function () {
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var result = null;
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if (reader.result) {
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result = new BlobView(blob, offset, length, reader.result, 0, length, littleEndian || false);
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}
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callback(result, reader.error);
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};
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};
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BlobView.getFromArrayBuffer = function (buffer, offset, length, littleEndian) {
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return new BlobView(null, offset, length, buffer, offset, length, littleEndian);
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};
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BlobView.prototype = {
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constructor: BlobView,
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getMore: function (offset, length, callback) {
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if (!this.blob) {
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fail('no blob backing this BlobView');
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}
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if (offset >= this.sliceOffset && offset + length <= this.sliceOffset + this.sliceLength) {
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callback(new BlobView(this.blob, this.sliceOffset, this.sliceLength, this.slice, offset - this.sliceOffset, length, this.littleEndian));
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} else {
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BlobView.get(this.blob, offset, length, callback, this.littleEndian);
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}
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},
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littleEndian: function () {
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this.littleEndian = true;
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},
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bigEndian: function () {
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this.littleEndian = false;
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},
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getUint8: function (offset) {
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return this.view.getUint8(offset);
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},
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getInt8: function (offset) {
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return this.view.getInt8(offset);
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},
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getUint16: function (offset, le) {
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return this.view.getUint16(offset, le !== undefined ? le : this.littleEndian);
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},
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getInt16: function (offset, le) {
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return this.view.getInt16(offset, le !== undefined ? le : this.littleEndian);
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},
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getUint32: function (offset, le) {
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return this.view.getUint32(offset, le !== undefined ? le : this.littleEndian);
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},
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getInt32: function (offset, le) {
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return this.view.getInt32(offset, le !== undefined ? le : this.littleEndian);
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},
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getFloat32: function (offset, le) {
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return this.view.getFloat32(offset, le !== undefined ? le : this.littleEndian);
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},
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getFloat64: function (offset, le) {
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return this.view.getFloat64(offset, le !== undefined ? le : this.littleEndian);
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},
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readByte: function () {
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return this.view.getInt8(this.index++);
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},
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readUnsignedByte: function () {
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return this.view.getUint8(this.index++);
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},
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readShort: function (le) {
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var val = this.view.getInt16(this.index, le !== undefined ? le : this.littleEndian);
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this.index += 2;
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return val;
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},
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readUnsignedShort: function (le) {
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var val = this.view.getUint16(this.index, le !== undefined ? le : this.littleEndian);
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this.index += 2;
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return val;
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},
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readInt: function (le) {
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var val = this.view.getInt32(this.index, le !== undefined ? le : this.littleEndian);
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this.index += 4;
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return val;
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},
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readUnsignedInt: function (le) {
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var val = this.view.getUint32(this.index, le !== undefined ? le : this.littleEndian);
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this.index += 4;
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return val;
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},
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readFloat: function (le) {
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var val = this.view.getFloat32(this.index, le !== undefined ? le : this.littleEndian);
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this.index += 4;
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return val;
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},
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readDouble: function (le) {
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var val = this.view.getFloat64(this.index, le !== undefined ? le : this.littleEndian);
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this.index += 8;
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return val;
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},
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tell: function () {
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return this.index;
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},
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remaining: function () {
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return this.byteLength - this.index;
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},
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seek: function (index) {
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if (index < 0) {
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fail('negative index');
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}
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if (index > this.byteLength) {
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fail('index greater than buffer size');
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}
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this.index = index;
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},
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advance: function (n) {
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var index = this.index + n;
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if (index < 0) {
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fail('advance past beginning of buffer');
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}
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if (index > this.byteLength) {
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fail('advance past end of buffer');
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}
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this.index = index;
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},
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getUnsignedByteArray: function (offset, n) {
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return new Uint8Array(this.buffer, offset + this.viewOffset, n);
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},
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readUnsignedByteArray: function (n) {
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var val = new Uint8Array(this.buffer, this.index + this.viewOffset, n);
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this.index += n;
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return val;
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},
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getBit: function (offset, bit) {
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var byte = this.view.getUint8(offset);
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return (byte & 1 << bit) !== 0;
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},
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getUint24: function (offset, le) {
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var b1, b2, b3;
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if (le !== undefined ? le : this.littleEndian) {
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b1 = this.view.getUint8(offset);
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b2 = this.view.getUint8(offset + 1);
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b3 = this.view.getUint8(offset + 2);
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} else {
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b3 = this.view.getUint8(offset);
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b2 = this.view.getUint8(offset + 1);
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b1 = this.view.getUint8(offset + 2);
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}
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return (b3 << 16) + (b2 << 8) + b1;
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},
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readUint24: function (le) {
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var value = this.getUint24(this.index, le);
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this.index += 3;
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return value;
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},
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getBinaryText: function (offset, len) {
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var bytes = new Uint8Array(this.buffer, offset + this.viewOffset, len);
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return String.fromCharCode.apply(String, bytes);
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},
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readBinaryText: function (len) {
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var s = this.getBinaryText(this.index, len);
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this.index += len;
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return s;
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},
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getLatin1Text: function (offset, len) {
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var bytes = new Uint8Array(this.buffer, offset + this.viewOffset, len);
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return getDecoder('latin1').decode(bytes);
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},
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readLatin1Text: function (len) {
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var s = this.getLatin1Text(this.index, len);
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this.index += len;
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return s;
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},
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getUTF8Text: function (offset, len) {
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var bytes = new Uint8Array(this.buffer, offset + this.viewOffset, len);
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return getDecoder('utf-8').decode(bytes);
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},
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readUTF8Text: function (len) {
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var s = this.getUTF8Text(this.index, len);
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this.index += len;
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return s;
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},
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getUTF16Text: function (offset, len, le) {
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if (len % 2) {
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fail('len must be a multiple of two');
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}
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var bytes = new Uint8Array(this.buffer, offset + this.viewOffset, len);
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if (le === null || le === undefined) {
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var BOM = (bytes[0] << 8) + bytes[1];
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if (BOM === 65279) {
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bytes = bytes.subarray(2);
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le = false;
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} else if (BOM === 65534) {
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bytes = bytes.subarray(2);
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le = true;
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} else {
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le = true;
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}
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}
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var encoding = le ? 'utf-16le' : 'utf-16be';
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return getDecoder(encoding).decode(bytes);
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},
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readUTF16Text: function (len, le) {
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var s = this.getUTF16Text(this.index, len, le);
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this.index += len;
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return s;
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},
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getID3Uint28BE: function (offset) {
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var b1 = this.view.getUint8(offset) & 127;
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var b2 = this.view.getUint8(offset + 1) & 127;
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var b3 = this.view.getUint8(offset + 2) & 127;
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var b4 = this.view.getUint8(offset + 3) & 127;
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return b1 << 21 | b2 << 14 | b3 << 7 | b4;
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},
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readID3Uint28BE: function () {
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var value = this.getID3Uint28BE(this.index);
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this.index += 4;
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return value;
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},
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readNullTerminatedLatin1Text: function (size, advance_by_size = false) {
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var bytes = new Uint8Array(this.buffer, this.viewOffset + this.index, size);
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var nil = bytes.indexOf(0);
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if (nil !== -1) {
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bytes = bytes.subarray(0, nil);
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}
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var s = getDecoder('latin1').decode(bytes);
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if (nil === -1 || advance_by_size) {
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this.index += size;
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} else {
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this.index += nil + 1;
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}
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return s;
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},
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readNullTerminatedUTF8Text: function (size, advance_by_size = false) {
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var bytes = new Uint8Array(this.buffer, this.viewOffset + this.index, size);
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var nil = bytes.indexOf(0);
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if (nil !== -1) {
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bytes = bytes.subarray(0, nil);
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}
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var s = getDecoder('utf-8').decode(bytes);
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if (nil === -1 || advance_by_size) {
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this.index += size;
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} else {
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this.index += nil + 1;
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}
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return s;
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},
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readNullTerminatedUTF16Text: function (size, le, advance_by_size = false) {
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if (size % 2) {
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fail('size must be a multiple of two');
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}
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for (var len = 0; len < size; len += 2) {
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if (this.getUint16(this.index + len, le) === 0) {
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break;
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}
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}
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var s = this.getUTF16Text(this.index, len, le);
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if (len === size || advance_by_size) {
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this.index += size;
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} else {
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this.index += len + 2;
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}
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return s;
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}
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};
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return {
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get: BlobView.get,
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getFromArrayBuffer: BlobView.getFromArrayBuffer
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};
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}(); |