chrome-devtools-frontend
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Chrome DevTools UI
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text/typescript
// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import * as Platform from '../platform/platform.js';
export class Segment<T> {
begin: number;
end: number;
data: T;
constructor(begin: number, end: number, data: T) {
if (begin > end) {
throw new Error('Invalid segment');
}
this.begin = begin;
this.end = end;
this.data = data;
}
intersects(that: Segment<T>): boolean {
return this.begin < that.end && that.begin < this.end;
}
}
export class SegmentedRange<T> {
#segmentsInternal: Segment<T>[];
readonly #mergeCallback: ((arg0: Segment<T>, arg1: Segment<T>) => Segment<T>| null)|undefined;
constructor(mergeCallback?: ((arg0: Segment<T>, arg1: Segment<T>) => Segment<T>| null)) {
this.#segmentsInternal = [];
this.#mergeCallback = mergeCallback;
}
append(newSegment: Segment<T>): void {
// 1. Find the proper insertion point for new segment
let startIndex =
Platform.ArrayUtilities.lowerBound(this.#segmentsInternal, newSegment, (a, b) => a.begin - b.begin);
let endIndex = startIndex;
let merged: (Segment<T>|null)|null = null;
if (startIndex > 0) {
// 2. Try mering the preceding segment
const precedingSegment = this.#segmentsInternal[startIndex - 1];
merged = this.tryMerge(precedingSegment, newSegment);
if (merged) {
--startIndex;
newSegment = merged;
} else if (this.#segmentsInternal[startIndex - 1].end >= newSegment.begin) {
// 2a. If merge failed and segments overlap, adjust preceding segment.
// If an old segment entirely contains new one, split it in two.
if (newSegment.end < precedingSegment.end) {
this.#segmentsInternal.splice(
startIndex, 0, new Segment<T>(newSegment.end, precedingSegment.end, precedingSegment.data));
}
precedingSegment.end = newSegment.begin;
}
}
// 3. Consume all segments that are entirely covered by the new one.
while (endIndex < this.#segmentsInternal.length && this.#segmentsInternal[endIndex].end <= newSegment.end) {
++endIndex;
}
// 4. Merge or adjust the succeeding segment if it overlaps.
if (endIndex < this.#segmentsInternal.length) {
merged = this.tryMerge(newSegment, this.#segmentsInternal[endIndex]);
if (merged) {
endIndex++;
newSegment = merged;
} else if (newSegment.intersects(this.#segmentsInternal[endIndex])) {
this.#segmentsInternal[endIndex].begin = newSegment.end;
}
}
this.#segmentsInternal.splice(startIndex, endIndex - startIndex, newSegment);
}
appendRange(that: SegmentedRange<T>): void {
that.segments().forEach(segment => this.append(segment));
}
segments(): Segment<T>[] {
return this.#segmentsInternal;
}
private tryMerge(first: Segment<T>, second: Segment<T>): Segment<T>|null {
const merged = this.#mergeCallback && this.#mergeCallback(first, second);
if (!merged) {
return null;
}
merged.begin = first.begin;
merged.end = Math.max(first.end, second.end);
return merged;
}
}