@thi.ng/buffers/fifo.js

General purpose and generic read/write buffer implementations with different behaviors/orderings

import { assert } from "@thi.ng/errors/assert";
const fifo = (cap) => new FIFOBuffer(cap);
class FIFOBuffer {
  buf;
  rpos = 0;
  wpos = 0;
  len = 0;
  constructor(cap = 1) {
    assert(cap >= 1, `capacity must be >= 1`);
    this.buf = new Array(cap);
  }
  get length() {
    return this.len;
  }
  clear() {
    this.buf.fill(void 0);
  }
  copy() {
    const buf = new FIFOBuffer(1);
    buf.buf = this.buf.slice();
    buf.rpos = this.rpos;
    buf.wpos = this.wpos;
    buf.len = this.len;
    return buf;
  }
  readable() {
    return this.len > 0;
  }
  read() {
    const { buf, rpos } = this;
    const val = buf[rpos];
    buf[rpos] = void 0;
    this.rpos = (rpos + 1) % buf.length;
    this.len--;
    return val;
  }
  peek() {
    const { buf, rpos } = this;
    return buf[rpos];
  }
  writable() {
    return this.len < this.buf.length;
  }
  write(x) {
    const { buf, wpos } = this;
    buf[wpos] = x;
    this.wpos = (wpos + 1) % buf.length;
    this.len++;
    return true;
  }
}
export {
  FIFOBuffer,
  fifo
};