nes-emu/apu/synthesis/LengthCounter.js

A NES emulator

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;
/** A note length counter. It can be clocked to decrease its value and notify when it finishes. */
class LengthCounter {
  constructor() {
    this.counter = 0;
  }

  /** Decreases the counter unless `isHalted`. Unless `isEnabled`, it resets the counter to 0. */
  clock(isEnabled, isHalted) {
    if (!isEnabled) this.counter = 0;else if (this.counter > 0 && !isHalted) this.counter--;
  }

  /** Returns a snapshot of the current state. */
  getSaveState() {
    return {
      counter: this.counter
    };
  }

  /** Restores state from a snapshot. */
  setSaveState(saveState) {
    this.counter = saveState.counter;
  }

  /** Returns whether it finished counting or not. */
  get didFinish() {
    return this.counter === 0;
  }
}
exports.default = LengthCounter;