Alex Hochheiden
d0470670a1
`third_party/node/node_modules` is generated by `./mach vendor node`. Differential Revision: https://phabricator.services.mozilla.com/D320322
65 lines
1.6 KiB
JavaScript
65 lines
1.6 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Alexander Akait @alexander-akait
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*/
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"use strict";
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class LocConverter {
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/**
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* Creates an instance of LocConverter.
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* @param {string} input input
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*/
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constructor(input) {
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/** @type {string} */
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this._input = input;
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/** @type {number} */
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this.line = 1;
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/** @type {number} */
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this.column = 0;
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/** @type {number} */
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this.pos = 0;
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}
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/**
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* Returns location converter.
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* @param {number} pos position
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* @returns {LocConverter} location converter
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*/
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get(pos) {
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if (this.pos !== pos) {
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if (this.pos < pos) {
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// Advance: delta-bounded scan of [this.pos, pos), allocation-free
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// (unbounded index scans go quadratic on newline-free input).
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const input = this._input;
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let last = -1;
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for (let j = this.pos; j < pos; j++) {
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if (input.charCodeAt(j) === 10) {
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this.line++;
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last = j;
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}
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}
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this.column =
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last === -1 ? this.column + (pos - this.pos) : pos - last - 1;
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} else {
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// Retreat: count newlines crossed in (pos, this.pos), i.e.
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// exclude the newline at `this.pos` itself. By convention a
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// `\n` is the last column of its line, so when `this.pos`
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// sits on one we're already on the line containing it; only
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// newlines strictly **before** `this.pos` and at-or-after
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// `pos` represent crossed line boundaries.
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let i = this._input.lastIndexOf("\n", this.pos - 1);
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while (i >= pos) {
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this.line--;
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i = i > 0 ? this._input.lastIndexOf("\n", i - 1) : -1;
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}
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this.column = i === -1 ? pos : pos - i - 1;
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}
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this.pos = pos;
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}
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return this;
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}
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}
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module.exports = LocConverter;
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