49 lines
994 B
TypeScript
49 lines
994 B
TypeScript
export class CircularBuffer<T> {
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private buf: T[]
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private head = 0
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private len = 0
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constructor(private capacity: number) {
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if (!Number.isInteger(capacity) || capacity <= 0) {
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throw new RangeError(`CircularBuffer capacity must be a positive integer, got ${capacity}`)
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}
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this.buf = new Array<T>(capacity)
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}
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push(item: T) {
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this.buf[this.head] = item
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this.head = (this.head + 1) % this.capacity
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if (this.len < this.capacity) {
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this.len++
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}
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}
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tail(n = this.len): T[] {
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const take = Math.min(Math.max(0, n), this.len)
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const start = this.len < this.capacity ? 0 : this.head
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const out: T[] = new Array<T>(take)
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for (let i = 0; i < take; i++) {
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out[i] = this.buf[(start + this.len - take + i) % this.capacity]!
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}
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return out
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}
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drain(): T[] {
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const out = this.tail()
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this.clear()
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return out
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}
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clear() {
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this.buf = new Array<T>(this.capacity)
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this.head = 0
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this.len = 0
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}
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}
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