cocos-enhance-kit/engine/cocos2d/renderer/memop/fixed-array.js

import sort from './timsort';

export default class FixedArray {
  constructor(size) {
    this._count = 0;
    this._data = new Array(size);
  }

  _resize(size) {
    if (size > this._data.length) {
      for (let i = this._data.length; i < size; ++i) {
        this._data[i] = undefined;
      }
    }
  }

  get length() {
    return this._count;
  }

  get data() {
    return this._data;
  }

  reset() {
    for (let i = 0; i < this._count; ++i) {
      this._data[i] = undefined;
    }

    this._count = 0;
  }

  push(val) {
    if (this._count >= this._data.length) {
      this._resize(this._data.length * 2);
    }

    this._data[this._count] = val;
    ++this._count;
  }

  pop() {
    --this._count;

    if (this._count < 0) {
      this._count = 0;
    }

    let ret = this._data[this._count];
    this._data[this._count] = undefined;

    return ret;
  }

  fastRemove(idx) {
    if (idx >= this._count || idx < 0) {
      return;
    }

    let last = this._count - 1;
    this._data[idx] = this._data[last];
    this._data[last] = undefined;
    this._count -= 1;
  }

  indexOf(val) {
    return this._data.indexOf(val);
  }

  sort(cmp) {
    return sort(this._data, 0, this._count, cmp);
  }
}