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ttyrec.js
53 lines (42 loc) · 1.41 KB
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ttyrec.js
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async function parse(response, { encoding }) {
const textDecoder = new TextDecoder(encoding);
const buffer = await response.arrayBuffer();
const array = new Uint8Array(buffer);
const firstFrame = parseFrame(array);
const baseTime = firstFrame.time;
const firstFrameText = textDecoder.decode(firstFrame.data);
const sizeMatch = firstFrameText.match(/\x1b\[8;(\d+);(\d+)t/);
const events = [];
let cols = 80;
let rows = 24;
if (sizeMatch !== null) {
cols = parseInt(sizeMatch[2], 10);
rows = parseInt(sizeMatch[1], 10);
}
let cursor = 0;
let frame = parseFrame(array);
while (frame !== undefined) {
const time = frame.time - baseTime;
const text = textDecoder.decode(frame.data);
events.push([time, "o", text]);
cursor += frame.len;
frame = parseFrame(array.subarray(cursor));
}
return { cols, rows, events };
}
function parseFrame(array) {
if (array.length < 13) return;
const time = parseTimestamp(array.subarray(0, 8));
const len = parseNumber(array.subarray(8, 12));
const data = array.subarray(12, 12 + len);
return { time, data, len: len + 12 };
}
function parseNumber(array) {
return array[0] + array[1] * 256 + array[2] * 256 * 256 + array[3] * 256 * 256 * 256;
}
function parseTimestamp(array) {
const sec = parseNumber(array.subarray(0, 4));
const usec = parseNumber(array.subarray(4, 8));
return sec + usec / 1000000;
}
export default parse;