forked from M3-Academy/challenge-algorithms-v2.0
80 lines
2.3 KiB
JavaScript
80 lines
2.3 KiB
JavaScript
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/* -*- Mode: js; js-indent-level: 2; -*- */
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/*
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* Copyright 2014 Mozilla Foundation and contributors
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* Licensed under the New BSD license. See LICENSE or:
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* http://opensource.org/licenses/BSD-3-Clause
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*/
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var util = require('./util');
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/**
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* Determine whether mappingB is after mappingA with respect to generated
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* position.
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*/
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function generatedPositionAfter(mappingA, mappingB) {
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// Optimized for most common case
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var lineA = mappingA.generatedLine;
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var lineB = mappingB.generatedLine;
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var columnA = mappingA.generatedColumn;
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var columnB = mappingB.generatedColumn;
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return lineB > lineA || lineB == lineA && columnB >= columnA ||
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util.compareByGeneratedPositionsInflated(mappingA, mappingB) <= 0;
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}
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/**
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* A data structure to provide a sorted view of accumulated mappings in a
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* performance conscious manner. It trades a neglibable overhead in general
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* case for a large speedup in case of mappings being added in order.
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*/
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function MappingList() {
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this._array = [];
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this._sorted = true;
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// Serves as infimum
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this._last = {generatedLine: -1, generatedColumn: 0};
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}
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/**
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* Iterate through internal items. This method takes the same arguments that
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* `Array.prototype.forEach` takes.
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*
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* NOTE: The order of the mappings is NOT guaranteed.
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*/
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MappingList.prototype.unsortedForEach =
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function MappingList_forEach(aCallback, aThisArg) {
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this._array.forEach(aCallback, aThisArg);
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};
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/**
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* Add the given source mapping.
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*
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* @param Object aMapping
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*/
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MappingList.prototype.add = function MappingList_add(aMapping) {
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if (generatedPositionAfter(this._last, aMapping)) {
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this._last = aMapping;
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this._array.push(aMapping);
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} else {
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this._sorted = false;
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this._array.push(aMapping);
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}
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};
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/**
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* Returns the flat, sorted array of mappings. The mappings are sorted by
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* generated position.
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*
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* WARNING: This method returns internal data without copying, for
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* performance. The return value must NOT be mutated, and should be treated as
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* an immutable borrow. If you want to take ownership, you must make your own
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* copy.
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*/
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MappingList.prototype.toArray = function MappingList_toArray() {
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if (!this._sorted) {
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this._array.sort(util.compareByGeneratedPositionsInflated);
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this._sorted = true;
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}
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return this._array;
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};
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exports.MappingList = MappingList;
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