| 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 readIdx: number |
| 14 | private writeIdx: number |
| 15 | private items: Array<T | undefined> |
| 16 | private readonly maxArrayIdx: number |
| 17 | public size: number |
| 18 | |
| 19 | /** |
| 20 | * @param size - Buffer size. @defaultValue defaultBufferSize |
| 21 | * @returns CircularBuffer. |
| 22 | */ |
| 23 | constructor (size: number = defaultBufferSize) { |
| 24 | this.checkSize(size) |
| 25 | this.readIdx = 0 |
| 26 | this.writeIdx = 0 |
| 27 | this.maxArrayIdx = size - 1 |
| 28 | this.size = 0 |
| 29 | this.items = new Array<T | undefined>(size) |
| 30 | } |
| 31 | |
| 32 | /** |
| 33 | * Checks whether the buffer is empty. |
| 34 | * |
| 35 | * @returns Whether the buffer is empty. |
| 36 | */ |
| 37 | public empty (): boolean { |
| 38 | return this.size === 0 |
| 39 | } |
| 40 | |
| 41 | /** |
| 42 | * Checks whether the buffer is full. |
| 43 | * |
| 44 | * @returns Whether the buffer is full. |
| 45 | */ |
| 46 | public full (): boolean { |
| 47 | return this.size === this.items.length |
| 48 | } |
| 49 | |
| 50 | /** |
| 51 | * Puts data into buffer. |
| 52 | * |
| 53 | * @param data - Data to put into buffer. |
| 54 | */ |
| 55 | public put (data: T): void { |
| 56 | this.items[this.writeIdx] = data |
| 57 | this.writeIdx = this.writeIdx === this.maxArrayIdx ? 0 : this.writeIdx + 1 |
| 58 | if (this.size < this.items.length) { |
| 59 | ++this.size |
| 60 | } |
| 61 | } |
| 62 | |
| 63 | /** |
| 64 | * Gets data from buffer. |
| 65 | * |
| 66 | * @returns Data from buffer. |
| 67 | */ |
| 68 | public get (): T | undefined { |
| 69 | const data = this.items[this.readIdx] |
| 70 | if (data == null) { |
| 71 | return |
| 72 | } |
| 73 | this.items[this.readIdx] = undefined |
| 74 | this.readIdx = this.readIdx === this.maxArrayIdx ? 0 : this.readIdx + 1 |
| 75 | --this.size |
| 76 | return data |
| 77 | } |
| 78 | |
| 79 | /** |
| 80 | * Returns buffer as array. |
| 81 | * |
| 82 | * @returns Array of buffer data. |
| 83 | */ |
| 84 | public toArray (): T[] { |
| 85 | return this.items.filter(item => item != null) as T[] |
| 86 | } |
| 87 | |
| 88 | private checkSize (size: number): void { |
| 89 | if (!Number.isSafeInteger(size)) { |
| 90 | throw new TypeError( |
| 91 | `Invalid circular buffer size: ${size} is not an integer` |
| 92 | ) |
| 93 | } |
| 94 | if (size < 0) { |
| 95 | throw new RangeError(`Invalid circular buffer size: ${size} < 0`) |
| 96 | } |
| 97 | } |
| 98 | } |