src/utils/CircularArray.ts

   1 export const DEFAULT_CIRCULAR_ARRAY_SIZE = 2000;
   2
   3 export class CircularArray<T> extends Array<T> {
   4   public size: number;
   5
   6   constructor(size: number = DEFAULT_CIRCULAR_ARRAY_SIZE, ...items: T[]) {
   7     super();
   8     this.checkSize(size);
   9     this.size = size;
  10     if (arguments.length > 1) {
  11       this.push(...items);
  12     }
  13   }
  14
  15   public push(...items: T[]): number {
  16     const length = super.push(...items);
  17     if (length > this.size) {
  18       super.splice(0, length - this.size);
  19     }
  20     return this.length;
  21   }
  22
  23   public unshift(...items: T[]): number {
  24     const length = super.unshift(...items);
  25     if (length > this.size) {
  26       super.splice(this.size, items.length);
  27     }
  28     return this.length;
  29   }
  30
  31   public concat(...items: (T | ConcatArray<T>)[]): CircularArray<T> {
  32     const concatenatedCircularArray = super.concat(
  33       items as T[]
  34     ) as CircularArray<T>;
  35     concatenatedCircularArray.size = this.size;
  36     if (concatenatedCircularArray.length > concatenatedCircularArray.size) {
  37       concatenatedCircularArray.splice(
  38         0,
  39         concatenatedCircularArray.length - concatenatedCircularArray.size
  40       );
  41     }
  42     return concatenatedCircularArray;
  43   }
  44
  45   public splice(start: number, deleteCount?: number, ...items: T[]): T[] {
  46     let itemsRemoved: T[];
  47     if (arguments.length >= 3 && typeof deleteCount !== 'undefined') {
  48       itemsRemoved = super.splice(start, deleteCount);
  49       // FIXME: that makes the items insert not in place
  50       this.push(...items);
  51     } else if (arguments.length === 2) {
  52       itemsRemoved = super.splice(start, deleteCount);
  53     } else {
  54       itemsRemoved = super.splice(start);
  55     }
  56     return itemsRemoved;
  57   }
  58
  59   public resize(size: number): void {
  60     this.checkSize(size);
  61     if (size === 0) {
  62       this.length = 0;
  63     } else if (size < this.size) {
  64       for (let i = size; i < this.size; i++) {
  65         super.pop();
  66       }
  67     }
  68     this.size = size;
  69   }
  70
  71   public empty(): boolean {
  72     return this.length === 0;
  73   }
  74
  75   public full(): boolean {
  76     return this.length === this.size;
  77   }
  78
  79   private checkSize(size: number) {
  80     if (size < 0) {
  81       throw new RangeError('Invalid circular array size');
  82     }
  83   }
  84 }