65 lines
1.2 KiB
JavaScript
65 lines
1.2 KiB
JavaScript
function Fun() {
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return {
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defaultCompare: defaultCompare,
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defined: defined,
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insert: insert,
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map: map,
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mapFilter: mapFilter,
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of: of,
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proj: proj
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};
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function insert(obj, t, compare, min, max) {
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min = min == undefined ? 0 : min;
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max = max == undefined ? t.length : max;
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compare = compare == undefined ? defaultCompare : compare;
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if(max - min < 1) {
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return min;
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}
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var avg = Math.floor((max + min) / 2);
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if (compare(obj, t[avg]) < 0) {
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return insert(obj, t, compare, min, avg);
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} else {
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return insert(obj, t, compare, avg+1, max);
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}
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}
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function defaultCompare(a, b) {
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if(a < b) {
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return -1;
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} else if(a > b) {
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return 1;
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} else {
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return 0;
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}
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}
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function map(mapper, f) {
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return function() {
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var args = Array.prototype.map.call(arguments, mapper);
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return f.apply(null, args);
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}
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}
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function of(o) {
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return function(key) {return o[key];};
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}
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function proj(key) {
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return function(o) {return o[key];};
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}
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function mapFilter(mapper, predicate) {
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return function(array) {
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return array.reduce(function(accumulator, elem) {
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var v = mapper(elem);
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return predicate(v) ? accumulator.concat(v) : accumulator;
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}, []);
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};
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}
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function defined(x) {
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return x != undefined;
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}
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}
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