47 lines
1.2 KiB
JavaScript
47 lines
1.2 KiB
JavaScript
/*jshint bitwise: false*/
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getJasmineRequireObj().Order = function() {
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function Order(options) {
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this.random = 'random' in options ? options.random : true;
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var seed = this.seed = options.seed || generateSeed();
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this.sort = this.random ? randomOrder : naturalOrder;
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function naturalOrder(items) {
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return items;
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}
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function randomOrder(items) {
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var copy = items.slice();
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copy.sort(function(a, b) {
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return jenkinsHash(seed + a.id) - jenkinsHash(seed + b.id);
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});
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return copy;
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}
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function generateSeed() {
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return String(Math.random()).slice(-5);
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}
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// Bob Jenkins One-at-a-Time Hash algorithm is a non-cryptographic hash function
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// used to get a different output when the key changes slighly.
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// We use your return to sort the children randomly in a consistent way when
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// used in conjunction with a seed
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function jenkinsHash(key) {
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var hash, i;
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for(hash = i = 0; i < key.length; ++i) {
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hash += key.charCodeAt(i);
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hash += (hash << 10);
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hash ^= (hash >> 6);
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}
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hash += (hash << 3);
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hash ^= (hash >> 11);
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hash += (hash << 15);
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return hash;
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}
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}
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return Order;
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};
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