tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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array-set.js (2394B)

      1 /* -*- Mode: js; js-indent-level: 2; -*- */
      2 /*
      3 * Copyright 2011 Mozilla Foundation and contributors
      4 * Licensed under the New BSD license. See LICENSE or:
      5 * http://opensource.org/licenses/BSD-3-Clause
      6 */
      7 
      8 /**
      9 * A data structure which is a combination of an array and a set. Adding a new
     10 * member is O(1), testing for membership is O(1), and finding the index of an
     11 * element is O(1). Removing elements from the set is not supported. Only
     12 * strings are supported for membership.
     13 */
     14 class ArraySet {
     15  constructor() {
     16    this._array = [];
     17    this._set = new Map();
     18  }
     19 
     20  /**
     21   * Static method for creating ArraySet instances from an existing array.
     22   */
     23  static fromArray(aArray, aAllowDuplicates) {
     24    const set = new ArraySet();
     25    for (let i = 0, len = aArray.length; i < len; i++) {
     26      set.add(aArray[i], aAllowDuplicates);
     27    }
     28    return set;
     29  }
     30 
     31  /**
     32   * Return how many unique items are in this ArraySet. If duplicates have been
     33   * added, than those do not count towards the size.
     34   *
     35   * @returns Number
     36   */
     37  size() {
     38    return this._set.size;
     39  }
     40 
     41  /**
     42   * Add the given string to this set.
     43   *
     44   * @param String aStr
     45   */
     46  add(aStr, aAllowDuplicates) {
     47    const isDuplicate = this.has(aStr);
     48    const idx = this._array.length;
     49    if (!isDuplicate || aAllowDuplicates) {
     50      this._array.push(aStr);
     51    }
     52    if (!isDuplicate) {
     53      this._set.set(aStr, idx);
     54    }
     55  }
     56 
     57  /**
     58   * Is the given string a member of this set?
     59   *
     60   * @param String aStr
     61   */
     62  has(aStr) {
     63    return this._set.has(aStr);
     64  }
     65 
     66  /**
     67   * What is the index of the given string in the array?
     68   *
     69   * @param String aStr
     70   */
     71  indexOf(aStr) {
     72    const idx = this._set.get(aStr);
     73    if (idx >= 0) {
     74      return idx;
     75    }
     76    throw new Error('"' + aStr + '" is not in the set.');
     77  }
     78 
     79  /**
     80   * What is the element at the given index?
     81   *
     82   * @param Number aIdx
     83   */
     84  at(aIdx) {
     85    if (aIdx >= 0 && aIdx < this._array.length) {
     86      return this._array[aIdx];
     87    }
     88    throw new Error("No element indexed by " + aIdx);
     89  }
     90 
     91  /**
     92   * Returns the array representation of this set (which has the proper indices
     93   * indicated by indexOf). Note that this is a copy of the internal array used
     94   * for storing the members so that no one can mess with internal state.
     95   */
     96  toArray() {
     97    return this._array.slice();
     98  }
     99 }
    100 exports.ArraySet = ArraySet;