61 lines
1.4 KiB
JavaScript
61 lines
1.4 KiB
JavaScript
/*global $, Whisper, Backbone, textsecure, extension*/
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/*
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* vim: ts=4:sw=4:expandtab
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*/
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// A bidirectional hash that allows constant-time lookup for
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// key -> value and value -> key
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(function () {
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'use strict';
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window.Whisper = window.Whisper || {};
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function Bimap (map1, map2) {
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if (typeof map1 !== 'string' || typeof map2 !== 'string') {
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throw 'Expected two map name strings as arguments';
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}
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this.bijection = {};
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this.bijection[map1] = map2;
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this.bijection[map2] = map1;
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// makes accessing the maps clearer
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this[map1] = {};
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this[map2] = {};
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this[map1 + 'From'] = function (key) { return this[map2][key]; };
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this[map2 + 'From'] = function (key) { return this[map1][key]; };
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}
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Bimap.prototype.add = function (obj) {
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if (typeof obj !== 'object') {
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throw 'Expected an object as an argument';
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}
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var keys = Object.keys(obj);
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var map1 = keys[0];
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var map2 = keys[1];
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if (this.bijection[map1] !== map2) {
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throw 'Expected the argument\'s keys to correspond to the Bimap\'s two map names';
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}
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this[map1][obj[map1]] = obj[map2];
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this[map2][obj[map2]] = obj[map1];
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};
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Bimap.prototype.remove = function remove (map, key) {
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var bijection = this.bijection[map];
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var correspondingKey = this[map][key];
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// delete from the bijection
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delete this[bijection][correspondingKey];
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// delete from the specified map
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delete this[map][key];
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return correspondingKey;
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};
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// export
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Whisper.Bimap = Bimap;
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})();
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