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47 lines
1.6 KiB
JavaScript
47 lines
1.6 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.CCTalkParser = void 0;
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const stream_1 = require("stream");
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/**
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* Parse the CCTalk protocol
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* @extends Transform
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*
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* A transform stream that emits CCTalk packets as they are received.
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*/
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class CCTalkParser extends stream_1.Transform {
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constructor(maxDelayBetweenBytesMs = 50) {
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super();
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this.array = [];
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this.cursor = 0;
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this.lastByteFetchTime = 0;
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this.maxDelayBetweenBytesMs = maxDelayBetweenBytesMs;
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}
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_transform(buffer, encoding, cb) {
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if (this.maxDelayBetweenBytesMs > 0) {
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const now = Date.now();
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if (now - this.lastByteFetchTime > this.maxDelayBetweenBytesMs) {
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this.array = [];
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this.cursor = 0;
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}
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this.lastByteFetchTime = now;
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}
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this.cursor += buffer.length;
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// TODO: Better Faster es7 no supported by node 4
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// ES7 allows directly push [...buffer]
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// this.array = this.array.concat(Array.from(buffer)) //Slower ?!?
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Array.from(buffer).map(byte => this.array.push(byte));
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while (this.cursor > 1 && this.cursor >= this.array[1] + 5) {
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// full frame accumulated
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// copy command from the array
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const FullMsgLength = this.array[1] + 5;
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const frame = Buffer.from(this.array.slice(0, FullMsgLength));
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// Preserve Extra Data
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this.array = this.array.slice(frame.length, this.array.length);
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this.cursor -= FullMsgLength;
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this.push(frame);
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}
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cb();
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}
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}
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exports.CCTalkParser = CCTalkParser;
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