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- /* -*- Mode: js; js-indent-level: 2; -*- */
- /*
- * Copyright 2011 Mozilla Foundation and contributors
- * Licensed under the New BSD license. See LICENSE or:
- * http://opensource.org/licenses/BSD-3-Clause
- */
- if (typeof define !== 'function') {
- var define = require('amdefine')(module, require);
- }
- define(function (require, exports, module) {
- var util = require('./util');
- /**
- * A data structure which is a combination of an array and a set. Adding a new
- * member is O(1), testing for membership is O(1), and finding the index of an
- * element is O(1). Removing elements from the set is not supported. Only
- * strings are supported for membership.
- */
- function ArraySet() {
- this._array = [];
- this._set = {};
- }
- /**
- * Static method for creating ArraySet instances from an existing array.
- */
- ArraySet.fromArray = function ArraySet_fromArray(aArray, aAllowDuplicates) {
- var set = new ArraySet();
- for (var i = 0, len = aArray.length; i < len; i++) {
- set.add(aArray[i], aAllowDuplicates);
- }
- return set;
- };
- /**
- * Add the given string to this set.
- *
- * @param String aStr
- */
- ArraySet.prototype.add = function ArraySet_add(aStr, aAllowDuplicates) {
- var isDuplicate = this.has(aStr);
- var idx = this._array.length;
- if (!isDuplicate || aAllowDuplicates) {
- this._array.push(aStr);
- }
- if (!isDuplicate) {
- this._set[util.toSetString(aStr)] = idx;
- }
- };
- /**
- * Is the given string a member of this set?
- *
- * @param String aStr
- */
- ArraySet.prototype.has = function ArraySet_has(aStr) {
- return Object.prototype.hasOwnProperty.call(this._set,
- util.toSetString(aStr));
- };
- /**
- * What is the index of the given string in the array?
- *
- * @param String aStr
- */
- ArraySet.prototype.indexOf = function ArraySet_indexOf(aStr) {
- if (this.has(aStr)) {
- return this._set[util.toSetString(aStr)];
- }
- throw new Error('"' + aStr + '" is not in the set.');
- };
- /**
- * What is the element at the given index?
- *
- * @param Number aIdx
- */
- ArraySet.prototype.at = function ArraySet_at(aIdx) {
- if (aIdx >= 0 && aIdx < this._array.length) {
- return this._array[aIdx];
- }
- throw new Error('No element indexed by ' + aIdx);
- };
- /**
- * Returns the array representation of this set (which has the proper indices
- * indicated by indexOf). Note that this is a copy of the internal array used
- * for storing the members so that no one can mess with internal state.
- */
- ArraySet.prototype.toArray = function ArraySet_toArray() {
- return this._array.slice();
- };
- exports.ArraySet = ArraySet;
- });
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