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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 import "dart:typed_data"; | 5 import "dart:typed_data"; |
6 | 6 |
7 // A VM patch of the dart:math library. | 7 // A VM patch of the dart:math library. |
8 | 8 |
9 // If [x] is an [int] and [exponent] is a non-negative [int], the result is | 9 // If [x] is an [int] and [exponent] is a non-negative [int], the result is |
10 // an [int], otherwise the result is a [double]. | 10 // an [int], otherwise the result is a [double]. |
11 @patch | 11 @patch num pow(num x, num exponent) { |
12 num pow(num x, num exponent) { | |
13 if ((x is int) && (exponent is int) && (exponent >= 0)) { | 12 if ((x is int) && (exponent is int) && (exponent >= 0)) { |
14 return _intPow(x, exponent); | 13 return _intPow(x, exponent); |
15 } | 14 } |
16 return _doublePow(x.toDouble(), exponent.toDouble()); | 15 return _doublePow(x.toDouble(), exponent.toDouble()); |
17 } | 16 } |
18 | 17 |
19 double _doublePow(double base, double exponent) { | 18 double _doublePow(double base, double exponent) { |
20 if (exponent == 0.0) { | 19 if (exponent == 0.0) { |
21 return 1.0; // ECMA-262 15.8.2.13 | 20 return 1.0; // ECMA-262 15.8.2.13 |
22 } | 21 } |
23 // Speed up simple cases. | 22 // Speed up simple cases. |
24 if (exponent == 1.0) return base; | 23 if (exponent == 1.0) return base; |
25 if (exponent == 2.0) return base * base; | 24 if (exponent == 2.0) return base * base; |
26 if (exponent == 3.0) return base * base * base; | 25 if (exponent == 3.0) return base * base * base; |
27 | 26 |
28 if (base == 1.0) return 1.0; | 27 if (base == 1.0) return 1.0; |
29 | 28 |
30 if (base.isNaN || exponent.isNaN) { | 29 if (base.isNaN || exponent.isNaN) { |
31 return double.NAN; | 30 return double.NAN; |
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50 } | 49 } |
51 exponent >>= 1; | 50 exponent >>= 1; |
52 // Skip unnecessary operation (can overflow to Mint or Bigint). | 51 // Skip unnecessary operation (can overflow to Mint or Bigint). |
53 if (exponent != 0) { | 52 if (exponent != 0) { |
54 base *= base; | 53 base *= base; |
55 } | 54 } |
56 } | 55 } |
57 return result; | 56 return result; |
58 } | 57 } |
59 | 58 |
60 @patch | 59 @patch double atan2(num a, num b) => _atan2(a.toDouble(), b.toDouble()); |
61 double atan2(num a, num b) => _atan2(a.toDouble(), b.toDouble()); | 60 @patch double sin(num x) => _sin(x.toDouble()); |
62 @patch | 61 @patch double cos(num x) => _cos(x.toDouble()); |
63 double sin(num x) => _sin(x.toDouble()); | 62 @patch double tan(num x) => _tan(x.toDouble()); |
64 @patch | 63 @patch double acos(num x) => _acos(x.toDouble()); |
65 double cos(num x) => _cos(x.toDouble()); | 64 @patch double asin(num x) => _asin(x.toDouble()); |
66 @patch | 65 @patch double atan(num x) => _atan(x.toDouble()); |
67 double tan(num x) => _tan(x.toDouble()); | 66 @patch double sqrt(num x) => _sqrt(x.toDouble()); |
68 @patch | 67 @patch double exp(num x) => _exp(x.toDouble()); |
69 double acos(num x) => _acos(x.toDouble()); | 68 @patch double log(num x) => _log(x.toDouble()); |
70 @patch | |
71 double asin(num x) => _asin(x.toDouble()); | |
72 @patch | |
73 double atan(num x) => _atan(x.toDouble()); | |
74 @patch | |
75 double sqrt(num x) => _sqrt(x.toDouble()); | |
76 @patch | |
77 double exp(num x) => _exp(x.toDouble()); | |
78 @patch | |
79 double log(num x) => _log(x.toDouble()); | |
80 | 69 |
81 double _atan2(double a, double b) native "Math_atan2"; | 70 double _atan2(double a, double b) native "Math_atan2"; |
82 double _sin(double x) native "Math_sin"; | 71 double _sin(double x) native "Math_sin"; |
83 double _cos(double x) native "Math_cos"; | 72 double _cos(double x) native "Math_cos"; |
84 double _tan(double x) native "Math_tan"; | 73 double _tan(double x) native "Math_tan"; |
85 double _acos(double x) native "Math_acos"; | 74 double _acos(double x) native "Math_acos"; |
86 double _asin(double x) native "Math_asin"; | 75 double _asin(double x) native "Math_asin"; |
87 double _atan(double x) native "Math_atan"; | 76 double _atan(double x) native "Math_atan"; |
88 double _sqrt(double x) native "Math_sqrt"; | 77 double _sqrt(double x) native "Math_sqrt"; |
89 double _exp(double x) native "Math_exp"; | 78 double _exp(double x) native "Math_exp"; |
90 double _log(double x) native "Math_log"; | 79 double _log(double x) native "Math_log"; |
91 | 80 |
| 81 |
92 // TODO(iposva): Handle patch methods within a patch class correctly. | 82 // TODO(iposva): Handle patch methods within a patch class correctly. |
93 @patch | 83 @patch class Random { |
94 class Random { | 84 |
95 @patch | 85 @patch factory Random([int seed]) { |
96 factory Random([int seed]) { | |
97 var state = _Random._setupSeed((seed == null) ? _Random._nextSeed() : seed); | 86 var state = _Random._setupSeed((seed == null) ? _Random._nextSeed() : seed); |
98 // Crank a couple of times to distribute the seed bits a bit further. | 87 // Crank a couple of times to distribute the seed bits a bit further. |
99 return new _Random._withState(state) | 88 return new _Random._withState(state).._nextState() |
100 .._nextState() | 89 .._nextState() |
101 .._nextState() | 90 .._nextState() |
102 .._nextState() | 91 .._nextState(); |
103 .._nextState(); | |
104 } | 92 } |
105 | 93 |
106 @patch | 94 @patch factory Random.secure() { |
107 factory Random.secure() { | |
108 return new _SecureRandom(); | 95 return new _SecureRandom(); |
109 } | 96 } |
110 } | 97 } |
111 | 98 |
| 99 |
112 class _Random implements Random { | 100 class _Random implements Random { |
113 // Internal state of the random number generator. | 101 // Internal state of the random number generator. |
114 final Uint32List _state; | 102 final Uint32List _state; |
115 static const _kSTATE_LO = 0; | 103 static const _kSTATE_LO = 0; |
116 static const _kSTATE_HI = 1; // Unused in Dart code. | 104 static const _kSTATE_HI = 1; // Unused in Dart code. |
117 | 105 |
118 _Random._withState(this._state); | 106 _Random._withState(this._state); |
119 | 107 |
120 // The algorithm used here is Multiply with Carry (MWC) with a Base b = 2^32. | 108 // The algorithm used here is Multiply with Carry (MWC) with a Base b = 2^32. |
121 // http://en.wikipedia.org/wiki/Multiply-with-carry | 109 // http://en.wikipedia.org/wiki/Multiply-with-carry |
122 // The constant A is selected from "Numerical Recipes 3rd Edition" p.348 B1. | 110 // The constant A is selected from "Numerical Recipes 3rd Edition" p.348 B1. |
123 | 111 |
124 // Implements: | 112 // Implements: |
125 // var state = | 113 // var state = |
126 // ((_A * (_state[_kSTATE_LO])) + _state[_kSTATE_HI]) & ((1 << 64) - 1); | 114 // ((_A * (_state[_kSTATE_LO])) + _state[_kSTATE_HI]) & ((1 << 64) - 1); |
127 // _state[_kSTATE_LO] = state & ((1 << 32) - 1); | 115 // _state[_kSTATE_LO] = state & ((1 << 32) - 1); |
128 // _state[_kSTATE_HI] = state >> 32; | 116 // _state[_kSTATE_HI] = state >> 32; |
129 // This is a native to prevent 64-bit operations in Dart, which | 117 // This is a native to prevent 64-bit operations in Dart, which |
130 // fail with --throw_on_javascript_int_overflow. | 118 // fail with --throw_on_javascript_int_overflow. |
131 // TODO(regis): Implement in Dart and remove Random_nextState in math.cc. | 119 // TODO(regis): Implement in Dart and remove Random_nextState in math.cc. |
132 void _nextState() native "Random_nextState"; | 120 void _nextState() native "Random_nextState"; |
133 | 121 |
134 int nextInt(int max) { | 122 int nextInt(int max) { |
135 const limit = 0x3FFFFFFF; | 123 const limit = 0x3FFFFFFF; |
136 if ((max <= 0) || ((max > limit) && (max > _POW2_32))) { | 124 if ((max <= 0) || ((max > limit) && (max > _POW2_32))) { |
137 throw new RangeError.range( | 125 throw new RangeError.range(max, 1, _POW2_32, "max", |
138 max, 1, _POW2_32, "max", "Must be positive and <= 2^32"); | 126 "Must be positive and <= 2^32"); |
139 } | 127 } |
140 if ((max & -max) == max) { | 128 if ((max & -max) == max) { |
141 // Fast case for powers of two. | 129 // Fast case for powers of two. |
142 _nextState(); | 130 _nextState(); |
143 return _state[_kSTATE_LO] & (max - 1); | 131 return _state[_kSTATE_LO] & (max - 1); |
144 } | 132 } |
145 | 133 |
146 var rnd32; | 134 var rnd32; |
147 var result; | 135 var result; |
148 do { | 136 do { |
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178 // Get a seed from the VM's random number provider. | 166 // Get a seed from the VM's random number provider. |
179 static Uint32List _initialSeed() native "Random_initialSeed"; | 167 static Uint32List _initialSeed() native "Random_initialSeed"; |
180 | 168 |
181 static int _nextSeed() { | 169 static int _nextSeed() { |
182 // Trigger the PRNG once to change the internal state. | 170 // Trigger the PRNG once to change the internal state. |
183 _prng._nextState(); | 171 _prng._nextState(); |
184 return _prng._state[_kSTATE_LO]; | 172 return _prng._state[_kSTATE_LO]; |
185 } | 173 } |
186 } | 174 } |
187 | 175 |
| 176 |
188 class _SecureRandom implements Random { | 177 class _SecureRandom implements Random { |
189 _SecureRandom() { | 178 _SecureRandom() { |
190 // Throw early in constructor if entropy source is not hooked up. | 179 // Throw early in constructor if entropy source is not hooked up. |
191 _getBytes(1); | 180 _getBytes(1); |
192 } | 181 } |
193 | 182 |
194 // Return count bytes of entropy as a positive integer; count <= 8. | 183 // Return count bytes of entropy as a positive integer; count <= 8. |
195 static int _getBytes(int count) native "SecureRandom_getBytes"; | 184 static int _getBytes(int count) native "SecureRandom_getBytes"; |
196 | 185 |
197 int nextInt(int max) { | 186 int nextInt(int max) { |
198 RangeError.checkValueInInterval( | 187 RangeError.checkValueInInterval( |
199 max, 1, _POW2_32, "max", "Must be positive and <= 2^32"); | 188 max, 1, _POW2_32, "max", "Must be positive and <= 2^32"); |
200 final byteCount = ((max - 1).bitLength + 7) >> 3; | 189 final byteCount = ((max - 1).bitLength + 7) >> 3; |
201 if (byteCount == 0) { | 190 if (byteCount == 0) { |
202 return 0; // Not random if max == 1. | 191 return 0; // Not random if max == 1. |
203 } | 192 } |
204 var rnd; | 193 var rnd; |
205 var result; | 194 var result; |
206 do { | 195 do { |
207 rnd = _getBytes(byteCount); | 196 rnd = _getBytes(byteCount); |
208 result = rnd % max; | 197 result = rnd % max; |
209 } while ((rnd - result + max) > (1 << (byteCount << 3))); | 198 } while ((rnd - result + max) > (1 << (byteCount << 3))); |
210 return result; | 199 return result; |
211 } | 200 } |
212 | 201 |
213 double nextDouble() { | 202 double nextDouble() { |
214 return (_getBytes(7) >> 3) / _POW2_53_D; | 203 return (_getBytes(7) >> 3) / _POW2_53_D; |
215 } | 204 } |
216 | 205 |
217 bool nextBool() { | 206 bool nextBool() { |
218 return _getBytes(1).isEven; | 207 return _getBytes(1).isEven; |
219 } | 208 } |
220 | 209 |
221 // Constants used by the algorithm. | 210 // Constants used by the algorithm. |
222 static const _POW2_32 = 1 << 32; | 211 static const _POW2_32 = 1 << 32; |
223 static const _POW2_53_D = 1.0 * (1 << 53); | 212 static const _POW2_53_D = 1.0 * (1 << 53); |
224 } | 213 } |
| 214 |
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