94 lines
2.2 KiB
TypeScript
94 lines
2.2 KiB
TypeScript
/*
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Original work Copyright (C) 2013 Julian Gruber <julian@juliangruber.com>
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Modified work Copyright (C) 2021 Taler Systems S.A.
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Permission is hereby granted, free of charge, to any person obtaining a
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copy of this software and associated documentation files (the "Software"),
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to deal in the Software without restriction, including without limitation
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the rights to use, copy, modify, merge, publish, distribute, sublicense,
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and/or sell copies of the Software, and to permit persons to whom the
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Software is furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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*/
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export function balanced(a: RegExp | string, b: RegExp | string, str: string) {
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let myA: string;
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let myB: string;
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if (a instanceof RegExp) myA = maybeMatch(a, str)!;
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else myA = a;
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if (b instanceof RegExp) myB = maybeMatch(b, str)!;
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else myB = b;
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const r = range(myA, myB, str);
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return (
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r && {
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start: r[0],
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end: r[1],
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pre: str.slice(0, r[0]),
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body: str.slice(r[0]! + myA!.length, r[1]),
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post: str.slice(r[1]! + myB!.length),
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}
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);
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}
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/**
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* @param {RegExp} reg
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* @param {string} str
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*/
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function maybeMatch(reg: RegExp, str: string) {
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const m = str.match(reg);
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return m ? m[0] : null;
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}
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balanced.range = range;
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/**
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* @param {string} a
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* @param {string} b
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* @param {string} str
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*/
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function range(a: string, b: string, str: string) {
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let begs: number[];
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let beg: number;
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let left, right, result;
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let ai = str.indexOf(a);
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let bi = str.indexOf(b, ai + 1);
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let i = ai;
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if (ai >= 0 && bi > 0) {
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if (a === b) {
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return [ai, bi];
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}
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begs = [];
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left = str.length;
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while (i >= 0 && !result) {
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if (i === ai) {
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begs.push(i);
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ai = str.indexOf(a, i + 1);
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} else if (begs.length === 1) {
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result = [begs.pop(), bi];
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} else {
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beg = begs.pop()!;
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if (beg < left) {
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left = beg;
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right = bi;
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}
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bi = str.indexOf(b, i + 1);
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}
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i = ai < bi && ai >= 0 ? ai : bi;
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}
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if (begs.length) {
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result = [left, right];
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}
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}
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return result;
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}
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