com.google.javascript.jscomp.js.es6.math.imul.js Maven / Gradle / Ivy
/*
* Copyright 2016 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'require util/polyfill';
$jscomp.polyfill('Math.imul', function(orig) {
if (orig) return orig;
/**
* Performs C-like 32-bit signed integer multiplication.
*
* Polyfills the static function Math.imul().
*
* @param {number} a Any number, or value that can be coerced to a number.
* @param {number} b Any number, or value that can be coerced to a number.
* @return {number} The 32-bit integer product of a and b.
*/
var polyfill = function(a, b) {
// This algorithm is taken from v8.
// Note: If multiplication overflows 32 bits, then we risk losing
// precision. We must therefore break the inputs into 16-bit
// words and multiply separately.
a = Number(a);
b = Number(b);
var ah = (a >>> 16) & 0xFFFF; // Treat individual words as unsigned
var al = a & 0xFFFF;
var bh = (b >>> 16) & 0xFFFF;
var bl = b & 0xFFFF;
var lh = ((ah * bl + al * bh) << 16) >>> 0; // >>> 0 casts to uint
return (al * bl + lh) | 0; // | 0 casts back to signed
};
return polyfill;
}, 'es6', 'es3');