src/circular-buffer.ts

   1 /**
   2  * Default buffer size.
   3  */
   4 export const defaultBufferSize = 2048
   5
   6 /**
   7  * Circular buffer
   8  *
   9  * @typeParam T - Type of buffer data.
  10  * @internal
  11  */
  12 export class CircularBuffer<T> {
  13   private readonly readIdx: number
  14   private writeIdx: number
  15   private items: Array<T | undefined>
  16   private readonly maxArrayIdx: number
  17
  18   /**
  19    * @param size - Buffer size. @defaultValue defaultBufferSize
  20    * @returns CircularBuffer.
  21    */
  22   constructor (size: number = defaultBufferSize) {
  23     this.checkSize(size)
  24     this.readIdx = 0
  25     this.writeIdx = 0
  26     this.maxArrayIdx = size - 1
  27     this.items = new Array<T | undefined>(size)
  28   }
  29
  30   /**
  31    * Puts data into buffer.
  32    *
  33    * @param data - Data to put into buffer.
  34    */
  35   public put (data: T): void {
  36     this.items[this.writeIdx] = data
  37     this.writeIdx = this.writeIdx === this.maxArrayIdx ? 0 : this.writeIdx + 1
  38   }
  39
  40   /**
  41    * Returns buffer as array.
  42    *
  43    * @returns Array of buffer data.
  44    */
  45   public toArray (): T[] {
  46     return this.items.filter(item => item != null) as T[]
  47   }
  48
  49   private checkSize (size: number): void {
  50     if (!Number.isSafeInteger(size)) {
  51       throw new TypeError(
  52         `Invalid circular buffer size: ${size} is not an integer`
  53       )
  54     }
  55     if (size < 0) {
  56       throw new RangeError(`Invalid circular buffer size: ${size} < 0`)
  57     }
  58   }
  59 }