| // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| // A VM patch of the dart:math library. |
| patch num pow(num x, num exponent) => MathNatives.pow(x, exponent); |
| patch double atan2(num a, num b) => MathNatives.atan2(a, b); |
| patch double sin(num x) => MathNatives.sin(x); |
| patch double cos(num x) => MathNatives.cos(x); |
| patch double tan(num x) => MathNatives.tan(x); |
| patch double acos(num x) => MathNatives.acos(x); |
| patch double asin(num x) => MathNatives.asin(x); |
| patch double atan(num x) => MathNatives.atan(x); |
| patch double sqrt(num x) => MathNatives.sqrt(x); |
| patch double exp(num x) => MathNatives.exp(x); |
| patch double log(num x) => MathNatives.log(x); |
| |
| |
| // TODO(iposva): Handle patch methods within a patch class correctly. |
| patch class Random { |
| |
| /*patch*/ factory Random([int seed]) { |
| if (seed == null) { |
| seed = _Random._nextSeed(); |
| } |
| do { |
| seed = (seed + 0x5A17) & _Random._MASK_64; |
| } while (seed == 0); |
| return new _Random._internal(seed); |
| } |
| } |
| |
| |
| class _Random implements Random { |
| // Internal state of the random number generator. |
| var _state; |
| |
| _Random._internal(this._state); |
| |
| // The algorithm used here is Multiply with Carry (MWC) with a Base b = 2^32. |
| // http://en.wikipedia.org/wiki/Multiply-with-carry |
| // The constant A is selected from "Numerical Recipes 3rd Edition" p.348 B1. |
| int _nextInt32() { |
| _state = ((_A * (_state & _MASK_32)) + (_state >> 32)) & _MASK_64; |
| return _state & _MASK_32; |
| } |
| |
| int nextInt(int max) { |
| if (max <= 0 || max > _POW2_32) { |
| throw new ArgumentError("max must be positive and < 2^32:" |
| " $max"); |
| } |
| if ((max & -max) == max) { |
| // Fast case for powers of two. |
| return _nextInt32() & (max - 1); |
| } |
| |
| var rnd32; |
| var result; |
| do { |
| rnd32 = _nextInt32(); |
| result = rnd32 % max; |
| } while ((rnd32 - result + max) >= _POW2_32); |
| return result; |
| } |
| |
| double nextDouble() { |
| return ((nextInt(1 << 26) << 27) + nextInt(1 << 27)) / _POW2_53_D; |
| } |
| |
| bool nextBool() { |
| return nextInt(2) == 0; |
| } |
| |
| // Constants used by the algorithm or masking. |
| static const _MASK_32 = (1 << 32) - 1; |
| static const _MASK_64 = (1 << 64) - 1; |
| static const _POW2_32 = 1 << 32; |
| static const _POW2_53_D = 1.0 * (1 << 53); |
| |
| static const _A = 0xffffda61; |
| |
| // Use a singleton Random object to get a new seed if no seed was passed. |
| static var _prng = null; |
| |
| static int _nextSeed() { |
| if (_prng == null) { |
| // TODO(iposva): Use system to get a random seed. |
| _prng = new Random(new Date.now().millisecondsSinceEpoch); |
| } |
| // Trigger the PRNG once to change the internal state. |
| _prng._nextInt32(); |
| return _prng._state; |
| } |
| } |