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 #if PLATFORM(BREWMP)
44 #include <AEEAppGen.h>
45 #include <AEESource.h>
46 #include <AEEStdLib.h>
47 #endif
48
49 namespace WTF {
50
weakRandomNumber()51 double weakRandomNumber()
52 {
53 #if COMPILER(MSVC) && defined(_CRT_RAND_S)
54 // rand_s is incredibly slow on windows so we fall back on rand for Math.random
55 return (rand() + (rand() / (RAND_MAX + 1.0))) / (RAND_MAX + 1.0);
56 #elif PLATFORM(BREWMP)
57 uint32_t bits;
58 GETRAND(reinterpret_cast<byte*>(&bits), sizeof(uint32_t));
59 return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0);
60 #else
61 return randomNumber();
62 #endif
63 }
64
randomNumber()65 double randomNumber()
66 {
67 #if !ENABLE(JSC_MULTIPLE_THREADS)
68 static bool s_initialized = false;
69 if (!s_initialized) {
70 initializeRandomNumberGenerator();
71 s_initialized = true;
72 }
73 #endif
74
75 #if COMPILER(MSVC) && defined(_CRT_RAND_S)
76 uint32_t bits;
77 rand_s(&bits);
78 return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0);
79 #elif OS(DARWIN)
80 uint32_t bits = arc4random();
81 return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0);
82 #elif OS(UNIX)
83 uint32_t part1 = random() & (RAND_MAX - 1);
84 uint32_t part2 = random() & (RAND_MAX - 1);
85 // random only provides 31 bits
86 uint64_t fullRandom = part1;
87 fullRandom <<= 31;
88 fullRandom |= part2;
89
90 // Mask off the low 53bits
91 fullRandom &= (1LL << 53) - 1;
92 return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53);
93 #elif OS(WINCE)
94 return genrand_res53();
95 #elif OS(WINDOWS)
96 uint32_t part1 = rand() & (RAND_MAX - 1);
97 uint32_t part2 = rand() & (RAND_MAX - 1);
98 uint32_t part3 = rand() & (RAND_MAX - 1);
99 uint32_t part4 = rand() & (RAND_MAX - 1);
100 // rand only provides 15 bits on Win32
101 uint64_t fullRandom = part1;
102 fullRandom <<= 15;
103 fullRandom |= part2;
104 fullRandom <<= 15;
105 fullRandom |= part3;
106 fullRandom <<= 15;
107 fullRandom |= part4;
108
109 // Mask off the low 53bits
110 fullRandom &= (1LL << 53) - 1;
111 return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53);
112 #elif PLATFORM(BREWMP)
113 uint32_t bits;
114 ISource* randomSource;
115
116 IShell* shell = reinterpret_cast<AEEApplet*>(GETAPPINSTANCE())->m_pIShell;
117 ISHELL_CreateInstance(shell, AEECLSID_RANDOM, reinterpret_cast<void**>(&randomSource));
118 ISOURCE_Read(randomSource, reinterpret_cast<char*>(&bits), 4);
119 ISOURCE_Release(randomSource);
120
121 return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0);
122 #else
123 uint32_t part1 = rand() & (RAND_MAX - 1);
124 uint32_t part2 = rand() & (RAND_MAX - 1);
125 // rand only provides 31 bits, and the low order bits of that aren't very random
126 // so we take the high 26 bits of part 1, and the high 27 bits of part2.
127 part1 >>= 5; // drop the low 5 bits
128 part2 >>= 4; // drop the low 4 bits
129 uint64_t fullRandom = part1;
130 fullRandom <<= 27;
131 fullRandom |= part2;
132
133 // Mask off the low 53bits
134 fullRandom &= (1LL << 53) - 1;
135 return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53);
136 #endif
137 }
138
139 }
140