48 lines
1.2 KiB
JavaScript
48 lines
1.2 KiB
JavaScript
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'use strict';
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var DataReader = require('./dataReader');
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function Uint8ArrayReader(data) {
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if (data) {
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this.data = data;
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this.length = this.data.length;
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this.index = 0;
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}
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}
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Uint8ArrayReader.prototype = new DataReader();
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/**
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* @see DataReader.byteAt
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*/
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Uint8ArrayReader.prototype.byteAt = function(i) {
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return this.data[i];
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};
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/**
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* @see DataReader.lastIndexOfSignature
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*/
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Uint8ArrayReader.prototype.lastIndexOfSignature = function(sig) {
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var sig0 = sig.charCodeAt(0),
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sig1 = sig.charCodeAt(1),
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sig2 = sig.charCodeAt(2),
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sig3 = sig.charCodeAt(3);
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for (var i = this.length - 4; i >= 0; --i) {
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if (this.data[i] === sig0 && this.data[i + 1] === sig1 && this.data[i + 2] === sig2 && this.data[i + 3] === sig3) {
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return i;
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}
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}
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return -1;
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};
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/**
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* @see DataReader.readData
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*/
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Uint8ArrayReader.prototype.readData = function(size) {
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this.checkOffset(size);
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if(size === 0) {
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// in IE10, when using subarray(idx, idx), we get the array [0x00] instead of [].
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return new Uint8Array(0);
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}
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var result = this.data.subarray(this.index, this.index + size);
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this.index += size;
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return result;
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};
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module.exports = Uint8ArrayReader;
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