1 | /* |
2 | * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved. |
3 | * (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/) |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
8 | * 1. Redistributions of source code must retain the above copyright |
9 | * notice, this list of conditions and the following disclaimer. |
10 | * 2. Redistributions in binary form must reproduce the above copyright |
11 | * notice, this list of conditions and the following disclaimer in the |
12 | * documentation and/or other materials provided with the distribution. |
13 | * |
14 | * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY |
15 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
17 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR |
18 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
19 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
20 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
21 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
22 | * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
24 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
25 | */ |
26 | |
27 | #include "config.h" |
28 | #include "RandomNumber.h" |
29 | |
30 | #include "RandomNumberSeed.h" |
31 | |
32 | #include <limits> |
33 | #include <limits.h> |
34 | #include <stdint.h> |
35 | #include <stdlib.h> |
36 | |
37 | #if OS(WINCE) |
38 | extern "C" { |
39 | #include "wince/mt19937ar.c" |
40 | } |
41 | #endif |
42 | |
43 | namespace WTF { |
44 | |
45 | double weakRandomNumber() |
46 | { |
47 | #if COMPILER(MSVC) && defined(_CRT_RAND_S) |
48 | // rand_s is incredibly slow on windows so we fall back on rand for Math.random |
49 | return (rand() + (rand() / (RAND_MAX + 1.0))) / (RAND_MAX + 1.0); |
50 | #else |
51 | return randomNumber(); |
52 | #endif |
53 | } |
54 | |
55 | double randomNumber() |
56 | { |
57 | #if !ENABLE(JSC_MULTIPLE_THREADS) |
58 | static bool s_initialized = false; |
59 | if (!s_initialized) { |
60 | initializeRandomNumberGenerator(); |
61 | s_initialized = true; |
62 | } |
63 | #endif |
64 | |
65 | #if COMPILER(MSVC) && defined(_CRT_RAND_S) |
66 | uint32_t bits; |
67 | rand_s(&bits); |
68 | return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0); |
69 | #elif OS(DARWIN) |
70 | uint32_t bits = arc4random(); |
71 | return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0); |
72 | #elif OS(UNIX) |
73 | uint32_t part1 = random() & (RAND_MAX - 1); |
74 | uint32_t part2 = random() & (RAND_MAX - 1); |
75 | // random only provides 31 bits |
76 | uint64_t fullRandom = part1; |
77 | fullRandom <<= 31; |
78 | fullRandom |= part2; |
79 | |
80 | // Mask off the low 53bits |
81 | fullRandom &= (1LL << 53) - 1; |
82 | return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53); |
83 | #elif OS(WINCE) |
84 | return genrand_res53(); |
85 | #elif OS(WINDOWS) |
86 | uint32_t part1 = rand() & (RAND_MAX - 1); |
87 | uint32_t part2 = rand() & (RAND_MAX - 1); |
88 | uint32_t part3 = rand() & (RAND_MAX - 1); |
89 | uint32_t part4 = rand() & (RAND_MAX - 1); |
90 | // rand only provides 15 bits on Win32 |
91 | uint64_t fullRandom = part1; |
92 | fullRandom <<= 15; |
93 | fullRandom |= part2; |
94 | fullRandom <<= 15; |
95 | fullRandom |= part3; |
96 | fullRandom <<= 15; |
97 | fullRandom |= part4; |
98 | |
99 | // Mask off the low 53bits |
100 | fullRandom &= (1LL << 53) - 1; |
101 | return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53); |
102 | #else |
103 | uint32_t part1 = rand() & (RAND_MAX - 1); |
104 | uint32_t part2 = rand() & (RAND_MAX - 1); |
105 | // rand only provides 31 bits, and the low order bits of that aren't very random |
106 | // so we take the high 26 bits of part 1, and the high 27 bits of part2. |
107 | part1 >>= 5; // drop the low 5 bits |
108 | part2 >>= 4; // drop the low 4 bits |
109 | uint64_t fullRandom = part1; |
110 | fullRandom <<= 27; |
111 | fullRandom |= part2; |
112 | |
113 | // Mask off the low 53bits |
114 | fullRandom &= (1LL << 53) - 1; |
115 | return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53); |
116 | #endif |
117 | } |
118 | |
119 | } |
120 | |