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 

    51 double randomNumber()

    52 {

    53 #if !ENABLE(JSC_MULTIPLE_THREADS)

    54     static bool s_initialized = false;

    55     if (!s_initialized) {

    56         initializeRandomNumberGenerator();

    57         s_initialized = true;

    58     }

    59 #endif

    60     

    61 #if COMPILER(MSVC) && defined(_CRT_RAND_S)

    62     uint32_t bits;

    63     rand_s(&bits);

    64     return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0);

    65 #elif OS(DARWIN)

    66     uint32_t bits = arc4random();

    67     return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0);

    68 #elif OS(UNIX)

    69     uint32_t part1 = random() & (RAND_MAX - 1);

    70     uint32_t part2 = random() & (RAND_MAX - 1);

    71     // random only provides 31 bits

    72     uint64_t fullRandom = part1;

    73     fullRandom <<= 31;

    74     fullRandom |= part2;

    75 

    76     // Mask off the low 53bits

    77     fullRandom &= (1LL << 53) - 1;

    78     return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53);

    79 #elif OS(WINCE)

    80     return genrand_res53();

    81 #elif OS(WINDOWS)

    82     uint32_t part1 = rand() & (RAND_MAX - 1);

    83     uint32_t part2 = rand() & (RAND_MAX - 1);

    84     uint32_t part3 = rand() & (RAND_MAX - 1);

    85     uint32_t part4 = rand() & (RAND_MAX - 1);

    86     // rand only provides 15 bits on Win32

    87     uint64_t fullRandom = part1;

    88     fullRandom <<= 15;

    89     fullRandom |= part2;

    90     fullRandom <<= 15;

    91     fullRandom |= part3;

    92     fullRandom <<= 15;

    93     fullRandom |= part4;

    94 

    95     // Mask off the low 53bits

    96     fullRandom &= (1LL << 53) - 1;

    97     return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53);

    98 #elif PLATFORM(BREWMP)

    99     uint32_t bits;

   100     ISource* randomSource;

   101 

   102     IShell* shell = reinterpret_cast<AEEApplet*>(GETAPPINSTANCE())->m_pIShell;

   103     ISHELL_CreateInstance(shell, AEECLSID_RANDOM, reinterpret_cast<void**>(&randomSource));

   104     ISOURCE_Read(randomSource, reinterpret_cast<char*>(&bits), 4);

   105     ISOURCE_Release(randomSource);

   106 

   107     return static_cast<double>(bits) / (static_cast<double>(std::numeric_limits<uint32_t>::max()) + 1.0);

   108 #else

   109     uint32_t part1 = rand() & (RAND_MAX - 1);

   110     uint32_t part2 = rand() & (RAND_MAX - 1);

   111     // rand only provides 31 bits, and the low order bits of that aren't very random

   112     // so we take the high 26 bits of part 1, and the high 27 bits of part2.

   113     part1 >>= 5; // drop the low 5 bits

   114     part2 >>= 4; // drop the low 4 bits

   115     uint64_t fullRandom = part1;

   116     fullRandom <<= 27;

   117     fullRandom |= part2;

   118 

   119     // Mask off the low 53bits

   120     fullRandom &= (1LL << 53) - 1;

   121     return static_cast<double>(fullRandom)/static_cast<double>(1LL << 53);

   122 #endif

   123 }

   124 

   125 }