Source: lib/polyfill/mathround.js

  1. /**
  2.  * @license
  3.  * Copyright 2016 Google Inc.
  4.  *
  5.  * Licensed under the Apache License, Version 2.0 (the "License");
  6.  * you may not use this file except in compliance with the License.
  7.  * You may obtain a copy of the License at
  8.  *
  9.  *     http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. goog.provide('shaka.polyfill.MathRound');
  19. goog.require('shaka.log');
  20. goog.require('shaka.polyfill.register');
  22. /**
  23.  * @namespace shaka.polyfill.MathRound
  24.  *
  25.  * @summary A polyfill to patch math round bug on some browsers.
  26.  * @see https://goo.gl/1XDi1W
  27.  */
  30. /**
  31.  @const {number}
  32.  @private
  33.  */
  34. shaka.polyfill.MathRound.MAX_ACCURATE_INPUT_ = 0x10000000000000;
  37. /**
  38.  * Install the polyfill if needed.
  39.  */
  40. shaka.polyfill.MathRound.install = function() {
  41.   shaka.log.debug('mathRound.install');
  43.   let testNumber = shaka.polyfill.MathRound.MAX_ACCURATE_INPUT_ + 1;
  44.   if (Math.round(testNumber) != testNumber) {
  45.     shaka.log.debug('polyfill Math.round');
  46.     let originalMathRound = Math.round;
  47.     Math.round = function(number) {
  48.       let result = number;
  49.       // Due to the precision of JavaScript numbers, the number must be integer.
  50.       if (number <= shaka.polyfill.MathRound.MAX_ACCURATE_INPUT_) {
  51.         result = originalMathRound(number);
  52.       }
  53.       return result;
  54.     };
  55.   }
  56. };
  58. shaka.polyfill.register(shaka.polyfill.MathRound.install);