| // 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. |
| |
| /// Note: the VM concatenates all patch files into a single patch file. This |
| /// file is the first patch in "dart:math" which contains all the imports used |
| /// by patches of that library. We plan to change this when we have a shared |
| /// front end and simply use parts. |
| |
| import "dart:_internal" show patch; |
| |
| import "dart:typed_data" show Uint32List; |
| |
| /// There are no parts of this patch library. |
| |
| @patch |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| T min<T extends num>(T a, T b) { |
| if (a > b) return b; |
| if (a < b) return a; |
| if (b is double) { |
| // Special case for NaN and -0.0. If one argument is NaN return NaN. |
| // [min] must also distinguish between -0.0 and 0.0. |
| if (a is double) { |
| if (a == 0.0) { |
| // a is either 0.0 or -0.0. b is either 0.0, -0.0 or NaN. |
| // The following returns -0.0 if either a or b is -0.0, and it |
| // returns NaN if b is NaN. |
| num n = (a + b) * a * b; |
| return n as T; |
| } |
| } |
| // Check for NaN and b == -0.0. |
| if (a == 0 && b.isNegative || b.isNaN) return b; |
| return a; |
| } |
| return a; |
| } |
| |
| @patch |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| T max<T extends num>(T a, T b) { |
| if (a > b) return a; |
| if (a < b) return b; |
| if (b is double) { |
| // Special case for NaN and -0.0. If one argument is NaN return NaN. |
| // [max] must also distinguish between -0.0 and 0.0. |
| if (a is double) { |
| if (a == 0.0) { |
| // a is either 0.0 or -0.0. b is either 0.0, -0.0, or NaN. |
| // The following returns 0.0 if either a or b is 0.0, and it |
| // returns NaN if b is NaN. |
| num n = a + b; |
| return n as T; |
| } |
| } |
| // Check for NaN. |
| if (b.isNaN) return b; |
| return a; |
| } |
| // max(-0.0, 0) must return 0. |
| if (b == 0 && a.isNegative) return b; |
| return a; |
| } |
| |
| // If [x] is an [int] and [exponent] is a non-negative [int], the result is |
| // an [int], otherwise the result is a [double]. |
| @patch |
| @pragma("vm:prefer-inline") |
| num pow(num x, num exponent) { |
| if ((x is int) && (exponent is int) && (exponent >= 0)) { |
| return _intPow(x, exponent); |
| } |
| return _doublePow(x.toDouble(), exponent.toDouble()); |
| } |
| |
| @pragma("vm:recognized", "other") |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| double _doublePow(double base, double exponent) { |
| if (exponent == 0.0) { |
| return 1.0; // ECMA-262 15.8.2.13 |
| } |
| // Speed up simple cases. |
| if (exponent == 1.0) return base; |
| if (exponent == 2.0) return base * base; |
| if (exponent == 3.0) return base * base * base; |
| |
| if (base == 1.0) return 1.0; |
| |
| if (base.isNaN || exponent.isNaN) { |
| return double.nan; |
| } |
| if ((base != -double.infinity) && (exponent == 0.5)) { |
| if (base == 0.0) { |
| return 0.0; |
| } |
| return sqrt(base); |
| } |
| return _pow(base.toDouble(), exponent.toDouble()); |
| } |
| |
| @pragma("vm:external-name", "Math_doublePow") |
| external double _pow(double base, double exponent); |
| |
| @pragma("vm:recognized", "other") |
| int _intPow(int base, int exponent) { |
| // Exponentiation by squaring. |
| int result = 1; |
| while (exponent != 0) { |
| if ((exponent & 1) == 1) { |
| result *= base; |
| } |
| exponent >>= 1; |
| // Skip unnecessary operation (can overflow to Mint). |
| if (exponent != 0) { |
| base *= base; |
| } |
| } |
| return result; |
| } |
| |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double atan2(num a, num b) => _atan2(a.toDouble(), b.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double sin(num radians) => _sin(radians.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double cos(num radians) => _cos(radians.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double tan(num radians) => _tan(radians.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double acos(num x) => _acos(x.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double asin(num x) => _asin(x.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double atan(num x) => _atan(x.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double sqrt(num x) => _sqrt(x.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double exp(num x) => _exp(x.toDouble()); |
| @patch |
| @pragma("vm:exact-result-type", "dart:core#_Double") |
| @pragma("vm:prefer-inline") |
| double log(num x) => _log(x.toDouble()); |
| |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _atan2(double a, double b); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _sin(double x); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _cos(double x); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _tan(double x); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _acos(double x); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _asin(double x); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _atan(double x); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _sqrt(double x); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _exp(double x); |
| @pragma("vm:recognized", "other") |
| @pragma("vm:prefer-inline") |
| external double _log(double x); |
| |
| // TODO(iposva): Handle patch methods within a patch class correctly. |
| @patch |
| class Random { |
| static final Random _secureRandom = _SecureRandom(); |
| |
| @patch |
| factory Random([int? seed]) { |
| var state = _Random._setupSeed((seed == null) ? _Random._nextSeed() : seed); |
| // Crank a couple of times to distribute the seed bits a bit further. |
| return new _Random._withState(state) |
| .._nextState() |
| .._nextState() |
| .._nextState() |
| .._nextState(); |
| } |
| |
| @patch |
| factory Random.secure() => _secureRandom; |
| } |
| |
| class _Random implements Random { |
| int _state; |
| |
| _Random._withState(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. |
| void _nextState() { |
| const A = 0xffffda61; |
| final state_lo = _state & 0xFFFFFFFF; |
| final state_hi = _state >>> 32; |
| _state = (A * state_lo) + state_hi; |
| } |
| |
| int nextInt(int max) { |
| const limit = 0x3FFFFFFF; |
| if ((max <= 0) || ((max > limit) && (max > _POW2_32))) { |
| throw new RangeError.range( |
| max, 1, _POW2_32, "max", "Must be positive and <= 2^32"); |
| } |
| if ((max & -max) == max) { |
| // Fast case for powers of two. |
| _nextState(); |
| return _state & 0xFFFFFFFF & (max - 1); |
| } |
| |
| var rnd32; |
| var result; |
| do { |
| _nextState(); |
| rnd32 = _state & 0xFFFFFFFF; |
| result = rnd32 % max; |
| } while ((rnd32 - result + max) > _POW2_32); |
| return result; |
| } |
| |
| double nextDouble() { |
| return ((nextInt(1 << 26) * _POW2_27_D) + nextInt(1 << 27)) / _POW2_53_D; |
| } |
| |
| bool nextBool() { |
| return nextInt(2) == 0; |
| } |
| |
| // Constants used by the algorithm. |
| static const _POW2_32 = 1 << 32; |
| static const _POW2_53_D = 1.0 * (1 << 53); |
| static const _POW2_27_D = 1.0 * (1 << 27); |
| |
| // Use a singleton Random object to get a new seed if no seed was passed. |
| static final _prng = new _Random._withState(_initialSeed()); |
| |
| // Thomas Wang 64-bit mix. |
| // http://www.concentric.net/~Ttwang/tech/inthash.htm |
| // via. http://web.archive.org/web/20071223173210/http://www.concentric.net/~Ttwang/tech/inthash.htm |
| static int _setupSeed(int n) { |
| n = (~n) + (n << 21); // n = (n << 21) - n - 1; |
| n = n ^ (n >>> 24); |
| n = n * 265; // n = (n + (n << 3)) + (n << 8); |
| n = n ^ (n >>> 14); |
| n = n * 21; // n = (n + (n << 2)) + (n << 4); |
| n = n ^ (n >>> 28); |
| n = n + (n << 31); |
| if (n == 0) { |
| n = 0x5a17; |
| } |
| return n; |
| } |
| |
| // Get a seed from the VM's random number provider. |
| @pragma("vm:external-name", "Random_initialSeed") |
| external static int _initialSeed(); |
| |
| static int _nextSeed() { |
| // Trigger the PRNG once to change the internal state. |
| _prng._nextState(); |
| return _prng._state & 0xFFFFFFFF; |
| } |
| } |
| |
| class _SecureRandom implements Random { |
| _SecureRandom() { |
| // Throw early in constructor if entropy source is not hooked up. |
| _getBytes(1); |
| } |
| |
| // Return count bytes of entropy as a positive integer; count <= 8. |
| @pragma("vm:external-name", "SecureRandom_getBytes") |
| external static int _getBytes(int count); |
| |
| int nextInt(int max) { |
| RangeError.checkValueInInterval( |
| max, 1, _POW2_32, "max", "Must be positive and <= 2^32"); |
| final byteCount = ((max - 1).bitLength + 7) >> 3; |
| if (byteCount == 0) { |
| return 0; // Not random if max == 1. |
| } |
| var rnd; |
| var result; |
| do { |
| rnd = _getBytes(byteCount); |
| result = rnd % max; |
| } while ((rnd - result + max) > (1 << (byteCount << 3))); |
| return result; |
| } |
| |
| double nextDouble() { |
| return (_getBytes(7) >> 3) / _POW2_53_D; |
| } |
| |
| bool nextBool() { |
| return _getBytes(1).isEven; |
| } |
| |
| // Constants used by the algorithm. |
| static const _POW2_32 = 1 << 32; |
| static const _POW2_53_D = 1.0 * (1 << 53); |
| } |