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Side by Side Diff: sdk/lib/_internal/compiler/js_lib/math_patch.dart

Issue 1212513002: sdk files reorganization to make dart2js a proper package (Closed) Base URL: git@github.com:dart-lang/sdk.git@master
Patch Set: renamed Created 5 years, 5 months ago
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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
3 // BSD-style license that can be found in the LICENSE file.
4
5 // Patch file for dart:math library.
6 import 'dart:_foreign_helper' show JS;
7 import 'dart:_js_helper' show patch, checkNum;
8
9 @patch
10 double sqrt(num x)
11 => JS('double', r'Math.sqrt(#)', checkNum(x));
12
13 @patch
14 double sin(num x)
15 => JS('double', r'Math.sin(#)', checkNum(x));
16
17 @patch
18 double cos(num x)
19 => JS('double', r'Math.cos(#)', checkNum(x));
20
21 @patch
22 double tan(num x)
23 => JS('double', r'Math.tan(#)', checkNum(x));
24
25 @patch
26 double acos(num x)
27 => JS('double', r'Math.acos(#)', checkNum(x));
28
29 @patch
30 double asin(num x)
31 => JS('double', r'Math.asin(#)', checkNum(x));
32
33 @patch
34 double atan(num x)
35 => JS('double', r'Math.atan(#)', checkNum(x));
36
37 @patch
38 double atan2(num a, num b)
39 => JS('double', r'Math.atan2(#, #)', checkNum(a), checkNum(b));
40
41 @patch
42 double exp(num x)
43 => JS('double', r'Math.exp(#)', checkNum(x));
44
45 @patch
46 double log(num x)
47 => JS('double', r'Math.log(#)', checkNum(x));
48
49 @patch
50 num pow(num x, num exponent) {
51 checkNum(x);
52 checkNum(exponent);
53 return JS('num', r'Math.pow(#, #)', x, exponent);
54 }
55
56 const int _POW2_32 = 0x100000000;
57
58 @patch
59 class Random {
60 @patch
61 factory Random([int seed]) =>
62 (seed == null) ? const _JSRandom() : new _Random(seed);
63 }
64
65 class _JSRandom implements Random {
66 // The Dart2JS implementation of Random doesn't use a seed.
67 const _JSRandom();
68
69 int nextInt(int max) {
70 if (max <= 0 || max > _POW2_32) {
71 throw new RangeError("max must be in range 0 < max ≤ 2^32, was $max");
72 }
73 return JS("int", "(Math.random() * #) >>> 0", max);
74 }
75
76 /**
77 * Generates a positive random floating point value uniformly distributed on
78 * the range from 0.0, inclusive, to 1.0, exclusive.
79 */
80 double nextDouble() => JS("double", "Math.random()");
81
82 /**
83 * Generates a random boolean value.
84 */
85 bool nextBool() => JS("bool", "Math.random() < 0.5");
86 }
87
88
89 class _Random implements Random {
90 // Constants used by the algorithm or masking.
91 static const double _POW2_53_D = 1.0 * (0x20000000000000);
92 static const double _POW2_27_D = 1.0 * (1 << 27);
93 static const int _MASK32 = 0xFFFFFFFF;
94
95 // State comprised of two unsigned 32 bit integers.
96 int _lo = 0;
97 int _hi = 0;
98
99 // Implements:
100 // uint64_t hash = 0;
101 // do {
102 // hash = hash * 1037 ^ mix64((uint64_t)seed);
103 // seed >>= 64;
104 // } while (seed != 0 && seed != -1); // Limits for pos/neg seed.
105 // if (hash == 0) {
106 // hash = 0x5A17;
107 // }
108 // _lo = hash & _MASK_32;
109 // _hi = hash >> 32;
110 // and then does four _nextState calls to shuffle bits around.
111 _Random(int seed) {
112 int empty_seed = 0;
113 if (seed < 0) {
114 empty_seed = -1;
115 }
116 do {
117 int low = seed & _MASK32;
118 seed = (seed - low) ~/ _POW2_32;
119 int high = seed & _MASK32;
120 seed = (seed - high) ~/ _POW2_32;
121
122 // Thomas Wang's 64-bit mix function.
123 // http://www.concentric.net/~Ttwang/tech/inthash.htm
124 // via. http://web.archive.org/web/20071223173210/http://www.concentric.ne t/~Ttwang/tech/inthash.htm
125
126 // key = ~key + (key << 21);
127 int tmplow = low << 21;
128 int tmphigh = (high << 21) | (low >> 11);
129 tmplow = (~low & _MASK32) + tmplow;
130 low = tmplow & _MASK32;
131 high = (~high + tmphigh + ((tmplow - low) ~/ 0x100000000)) & _MASK32;
132 // key = key ^ (key >> 24).
133 tmphigh = high >> 24;
134 tmplow = (low >> 24) | (high << 8);
135 low ^= tmplow;
136 high ^= tmphigh;
137 // key = key * 265
138 tmplow = low * 265;
139 low = tmplow & _MASK32;
140 high = (high * 265 + (tmplow - low) ~/ 0x100000000) & _MASK32;
141 // key = key ^ (key >> 14);
142 tmphigh = high >> 14;
143 tmplow = (low >> 14) | (high << 18);
144 low ^= tmplow;
145 high ^= tmphigh;
146 // key = key * 21
147 tmplow = low * 21;
148 low = tmplow & _MASK32;
149 high = (high * 21 + (tmplow - low) ~/ 0x100000000) & _MASK32;
150 // key = key ^ (key >> 28).
151 tmphigh = high >> 28;
152 tmplow = (low >> 28) | (high << 4);
153 low ^= tmplow;
154 high ^= tmphigh;
155 // key = key + (key << 31);
156 tmplow = low << 31;
157 tmphigh = (high << 31) | (low >> 1);
158 tmplow += low;
159 low = tmplow & _MASK32;
160 high = (high + tmphigh + (tmplow - low) ~/ 0x100000000) & _MASK32;
161 // Mix end.
162
163 // seed = seed * 1037 ^ key;
164 tmplow = _lo * 1037;
165 _lo = tmplow & _MASK32;
166 _hi = (_hi * 1037 + (tmplow - _lo) ~/ 0x100000000) & _MASK32;
167 _lo ^= low;
168 _hi ^= high;
169 } while (seed != empty_seed);
170
171 if (_hi == 0 && _lo == 0) {
172 _lo = 0x5A17;
173 }
174 _nextState();
175 _nextState();
176 _nextState();
177 _nextState();
178 }
179
180 // The algorithm used here is Multiply with Carry (MWC) with a Base b = 2^32.
181 // http://en.wikipedia.org/wiki/Multiply-with-carry
182 // The constant A (0xFFFFDA61) is selected from "Numerical Recipes 3rd
183 // Edition" p.348 B1.
184
185 // Implements:
186 // var state = (A * _lo + _hi) & _MASK_64;
187 // _lo = state & _MASK_32;
188 // _hi = state >> 32;
189 void _nextState() {
190 // Simulate (0xFFFFDA61 * lo + hi) without overflowing 53 bits.
191 int tmpHi = 0xFFFF0000 * _lo; // At most 48 bits of significant result.
192 int tmpHiLo = tmpHi & _MASK32; // Get the lower 32 bits.
193 int tmpHiHi = tmpHi - tmpHiLo; // And just the upper 32 bits.
194 int tmpLo = 0xDA61 * _lo;
195 int tmpLoLo = tmpLo & _MASK32;
196 int tmpLoHi = tmpLo - tmpLoLo;
197
198 int newLo = tmpLoLo + tmpHiLo + _hi;
199 _lo = newLo & _MASK32;
200 int newLoHi = newLo - _lo;
201 _hi = ((tmpLoHi + tmpHiHi + newLoHi) ~/ _POW2_32) & _MASK32;
202 assert(_lo < _POW2_32);
203 assert(_hi < _POW2_32);
204 }
205
206 int nextInt(int max) {
207 if (max <= 0 || max > _POW2_32) {
208 throw new RangeError("max must be in range 0 < max ≤ 2^32, was $max");
209 }
210 if ((max & (max - 1)) == 0) {
211 // Fast case for powers of two.
212 _nextState();
213 return _lo & (max - 1);
214 }
215
216 int rnd32;
217 int result;
218 do {
219 _nextState();
220 rnd32 = _lo;
221 result = rnd32.remainder(max); // % max;
222 } while ((rnd32 - result + max) >= _POW2_32);
223 return result;
224 }
225
226 double nextDouble() {
227 _nextState();
228 int bits26 = _lo & ((1 << 26) - 1);
229 _nextState();
230 int bits27 = _lo & ((1 << 27) - 1);
231 return (bits26 * _POW2_27_D + bits27) / _POW2_53_D;
232 }
233
234 bool nextBool() {
235 _nextState();
236 return (_lo & 1) == 0;
237 }
238 }
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