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      1 <!DOCTYPE html>
      2 <!--
      3 Copyright (c) 2014 The Chromium Authors. All rights reserved.
      4 Use of this source code is governed by a BSD-style license that can be
      5 found in the LICENSE file.
      6 -->
      7 
      8 <link rel="import" href="/base/base.html">
      9 
     10 <script>
     11 'use strict';
     12 
     13 /**
     14  * @fileoverview Quick range computations.
     15  */
     16 tr.exportTo('tr.b', function() {
     17 
     18   function Range() {
     19     this.isEmpty_ = true;
     20     this.min_ = undefined;
     21     this.max_ = undefined;
     22   };
     23 
     24   Range.prototype = {
     25     __proto__: Object.prototype,
     26 
     27     reset: function() {
     28       this.isEmpty_ = true;
     29       this.min_ = undefined;
     30       this.max_ = undefined;
     31     },
     32 
     33     get isEmpty() {
     34       return this.isEmpty_;
     35     },
     36 
     37     addRange: function(range) {
     38       if (range.isEmpty)
     39         return;
     40       this.addValue(range.min);
     41       this.addValue(range.max);
     42     },
     43 
     44     addValue: function(value) {
     45       if (this.isEmpty_) {
     46         this.max_ = value;
     47         this.min_ = value;
     48         this.isEmpty_ = false;
     49         return;
     50       }
     51       this.max_ = Math.max(this.max_, value);
     52       this.min_ = Math.min(this.min_, value);
     53     },
     54 
     55     set min(min) {
     56       this.isEmpty_ = false;
     57       this.min_ = min;
     58     },
     59 
     60     get min() {
     61       if (this.isEmpty_)
     62         return undefined;
     63       return this.min_;
     64     },
     65 
     66     get max() {
     67       if (this.isEmpty_)
     68         return undefined;
     69       return this.max_;
     70     },
     71 
     72     set max(max) {
     73       this.isEmpty_ = false;
     74       this.max_ = max;
     75     },
     76 
     77     get range() {
     78       if (this.isEmpty_)
     79         return undefined;
     80       return this.max_ - this.min_;
     81     },
     82 
     83     get center() {
     84       return (this.min_ + this.max_) * 0.5;
     85     },
     86 
     87     equals: function(that) {
     88       if (this.isEmpty && that.isEmpty)
     89         return true;
     90       if (this.isEmpty != that.isEmpty)
     91         return false;
     92       return this.min === that.min &&
     93           this.max === that.max;
     94     },
     95 
     96     containsRange: function(range) {
     97       if (this.isEmpty || range.isEmpty)
     98         return false;
     99       return this.min <= range.min && this.max >= range.max;
    100     },
    101 
    102     containsExplicitRange: function(min, max) {
    103       if (this.isEmpty)
    104         return false;
    105       return this.min <= min && this.max >= max;
    106     },
    107 
    108     intersectsRange: function(range) {
    109       if (this.isEmpty || range.isEmpty)
    110         return false;
    111       return !(range.max < this.min ||
    112                range.min > this.max);
    113     },
    114 
    115     intersectsExplicitRange: function(min, max) {
    116       if (this.isEmpty)
    117         return false;
    118       return !(max < this.min ||
    119                min > this.max);
    120     }
    121   };
    122 
    123   Range.fromExplicitRange = function(min, max) {
    124     var range = new Range();
    125     range.min = min;
    126     range.max = max;
    127     return range;
    128   };
    129 
    130   Range.compareByMinTimes = function(a, b) {
    131     if (!a.isEmpty && !b.isEmpty)
    132       return a.min_ - b.min_;
    133 
    134     if (a.isEmpty && !b.isEmpty)
    135       return -1;
    136 
    137     if (!a.isEmpty && b.isEmpty)
    138       return 1;
    139 
    140     return 0;
    141   };
    142 
    143   return {
    144     Range: Range
    145   };
    146 });
    147 </script>
    148