mirror of
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87 lines
2.0 KiB
JavaScript
87 lines
2.0 KiB
JavaScript
/**
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* @author n1474335 [n1474335@gmail.com]
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* @copyright Crown Copyright 2016
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* @license Apache-2.0
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*/
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import Operation from "../Operation";
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/**
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* Take bytes operation
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*/
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class TakeBytes extends Operation {
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/**
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* TakeBytes constructor
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*/
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constructor() {
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super();
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this.name = "Take bytes";
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this.module = "Default";
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this.description = "Takes a slice of the specified number of bytes from the data.";
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this.inputType = "ArrayBuffer";
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this.outputType = "ArrayBuffer";
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this.args = [
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{
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"name": "Start",
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"type": "number",
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"value": 0
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},
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{
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"name": "Length",
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"type": "number",
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"value": 5
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},
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{
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"name": "Apply to each line",
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"type": "boolean",
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"value": false
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}
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];
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}
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/**
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* @param {ArrayBuffer} input
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* @param {Object[]} args
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* @returns {ArrayBuffer}
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*/
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run(input, args) {
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const start = args[0],
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length = args[1],
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applyToEachLine = args[2];
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if (start < 0 || length < 0)
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throw "Error: Invalid value";
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if (!applyToEachLine)
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return input.slice(start, start+length);
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// Split input into lines
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const data = new Uint8Array(input);
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const lines = [];
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let line = [],
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i;
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for (i = 0; i < data.length; i++) {
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if (data[i] === 0x0a) {
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lines.push(line);
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line = [];
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} else {
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line.push(data[i]);
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}
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}
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lines.push(line);
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let output = [];
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for (i = 0; i < lines.length; i++) {
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output = output.concat(lines[i].slice(start, start+length));
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output.push(0x0a);
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}
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return new Uint8Array(output.slice(0, output.length-1)).buffer;
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}
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}
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export default TakeBytes;
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