source: trip-planner-front/node_modules/hdr-histogram-js/src/JsHistogramIterator.ts

Last change on this file was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

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1/*
2 * This is a TypeScript port of the original Java version, which was written by
3 * Gil Tene as described in
4 * https://github.com/HdrHistogram/HdrHistogram
5 * and released to the public domain, as explained at
6 * http://creativecommons.org/publicdomain/zero/1.0/
7 */
8import JsHistogram from "./JsHistogram";
9import HistogramIterationValue from "./HistogramIterationValue";
10
11/**
12 * Used for iterating through histogram values.
13 */
14abstract class JsHistogramIterator /* implements Iterator<HistogramIterationValue> */ {
15 histogram: JsHistogram;
16 savedHistogramTotalRawCount: number;
17 currentIndex: number;
18 currentValueAtIndex: number;
19 nextValueAtIndex: number;
20 prevValueIteratedTo: number;
21 totalCountToPrevIndex: number;
22 totalCountToCurrentIndex: number;
23 totalValueToCurrentIndex: number;
24 arrayTotalCount: number;
25 countAtThisValue: number;
26
27 private freshSubBucket: boolean;
28
29 currentIterationValue: HistogramIterationValue = new HistogramIterationValue();
30
31 resetIterator(histogram: JsHistogram) {
32 this.histogram = histogram;
33 this.savedHistogramTotalRawCount = histogram.totalCount;
34 this.arrayTotalCount = histogram.totalCount;
35 this.currentIndex = 0;
36 this.currentValueAtIndex = 0;
37 this.nextValueAtIndex = Math.pow(2, histogram.unitMagnitude);
38 this.prevValueIteratedTo = 0;
39 this.totalCountToPrevIndex = 0;
40 this.totalCountToCurrentIndex = 0;
41 this.totalValueToCurrentIndex = 0;
42 this.countAtThisValue = 0;
43 this.freshSubBucket = true;
44 this.currentIterationValue.reset();
45 }
46
47 /**
48 * Returns true if the iteration has more elements. (In other words, returns true if next would return an
49 * element rather than throwing an exception.)
50 *
51 * @return true if the iterator has more elements.
52 */
53 public hasNext(): boolean {
54 if (this.histogram.totalCount !== this.savedHistogramTotalRawCount) {
55 throw "Concurrent Modification Exception";
56 }
57 return this.totalCountToCurrentIndex < this.arrayTotalCount;
58 }
59
60 /**
61 * Returns the next element in the iteration.
62 *
63 * @return the {@link HistogramIterationValue} associated with the next element in the iteration.
64 */
65 public next(): HistogramIterationValue {
66 // Move through the sub buckets and buckets until we hit the next reporting level:
67 while (!this.exhaustedSubBuckets()) {
68 this.countAtThisValue = this.histogram.getCountAtIndex(this.currentIndex);
69 if (this.freshSubBucket) {
70 // Don't add unless we've incremented since last bucket...
71 this.totalCountToCurrentIndex += this.countAtThisValue;
72 this.totalValueToCurrentIndex +=
73 this.countAtThisValue *
74 this.histogram.highestEquivalentValue(this.currentValueAtIndex);
75 this.freshSubBucket = false;
76 }
77 if (this.reachedIterationLevel()) {
78 const valueIteratedTo = this.getValueIteratedTo();
79
80 Object.assign(this.currentIterationValue, {
81 valueIteratedTo,
82 valueIteratedFrom: this.prevValueIteratedTo,
83 countAtValueIteratedTo: this.countAtThisValue,
84 countAddedInThisIterationStep:
85 this.totalCountToCurrentIndex - this.totalCountToPrevIndex,
86 totalCountToThisValue: this.totalCountToCurrentIndex,
87 totalValueToThisValue: this.totalValueToCurrentIndex,
88 percentile:
89 (100 * this.totalCountToCurrentIndex) / this.arrayTotalCount,
90 percentileLevelIteratedTo: this.getPercentileIteratedTo(),
91 });
92
93 this.prevValueIteratedTo = valueIteratedTo;
94 this.totalCountToPrevIndex = this.totalCountToCurrentIndex;
95 this.incrementIterationLevel();
96 if (this.histogram.totalCount !== this.savedHistogramTotalRawCount) {
97 throw new Error("Concurrent Modification Exception");
98 }
99 return this.currentIterationValue;
100 }
101 this.incrementSubBucket();
102 }
103 throw new Error("Index Out Of Bounds Exception");
104 }
105
106 abstract incrementIterationLevel(): void;
107
108 /**
109 * @return true if the current position's data should be emitted by the iterator
110 */
111 abstract reachedIterationLevel(): boolean;
112
113 getPercentileIteratedTo(): number {
114 return (100 * this.totalCountToCurrentIndex) / this.arrayTotalCount;
115 }
116
117 getPercentileIteratedFrom(): number {
118 return (100 * this.totalCountToPrevIndex) / this.arrayTotalCount;
119 }
120
121 getValueIteratedTo(): number {
122 return this.histogram.highestEquivalentValue(this.currentValueAtIndex);
123 }
124
125 private exhaustedSubBuckets(): boolean {
126 return this.currentIndex >= this.histogram.countsArrayLength;
127 }
128
129 incrementSubBucket() {
130 this.freshSubBucket = true;
131 this.currentIndex++;
132 this.currentValueAtIndex = this.histogram.valueFromIndex(this.currentIndex);
133 this.nextValueAtIndex = this.histogram.valueFromIndex(
134 this.currentIndex + 1
135 );
136 }
137}
138
139export default JsHistogramIterator;
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