1 /*

     2  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions

     6  * are met:

     7  * 1. Redistributions of source code must retain the above copyright

     8  *    notice, this list of conditions and the following disclaimer.

     9  * 2. Redistributions in binary form must reproduce the above copyright

    10  *    notice, this list of conditions and the following disclaimer in the

    11  *    documentation and/or other materials provided with the distribution.

    12  *

    13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

    14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

    17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

    21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

    24  */

    25 

    26 #ifndef WTF_RandomNumberSeed_h

    27 #define WTF_RandomNumberSeed_h

    28 

    29 #include <stdlib.h>

    30 #include <time.h>

    31 

    32 #if HAVE(SYS_TIME_H)

    33 #include <sys/time.h>

    34 #endif

    35 

    36 #if OS(UNIX)

    37 #include <sys/types.h>

    38 #include <unistd.h>

    39 #endif

    40 

    41 #if OS(WINCE)

    42 extern "C" {

    43 void init_by_array(unsigned long init_key[],int key_length);

    44 }

    45 #endif

    46 

    47 // Internal JavaScriptCore usage only

    48 namespace WTF {

    49 

    50 inline void initializeRandomNumberGenerator()

    51 {

    52 #if OS(DARWIN)

    53     // On Darwin we use arc4random which initialises itself.

    54 #elif OS(WINCE)

    55     // initialize rand()

    56     srand(static_cast<unsigned>(time(0)));

    57 

    58     // use rand() to initialize the real RNG

    59     unsigned long initializationBuffer[4];

    60     initializationBuffer[0] = (rand() << 16) | rand();

    61     initializationBuffer[1] = (rand() << 16) | rand();

    62     initializationBuffer[2] = (rand() << 16) | rand();

    63     initializationBuffer[3] = (rand() << 16) | rand();

    64     init_by_array(initializationBuffer, 4);

    65 #elif COMPILER(MSVC) && defined(_CRT_RAND_S)

    66     // On Windows we use rand_s which initialises itself

    67 #elif OS(UNIX)

    68     // srandomdev is not guaranteed to exist on linux so we use this poor seed, this should be improved

    69     timeval time;

    70     gettimeofday(&time, 0);

    71     srandom(static_cast<unsigned>(time.tv_usec * getpid()));

    72 #else

    73     srand(static_cast<unsigned>(time(0)));

    74 #endif

    75 }

    76 

    77 inline void initializeWeakRandomNumberGenerator()

    78 {

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

    80     // We need to initialise windows rand() explicitly for Math.random

    81     unsigned seed = 0;

    82     rand_s(&seed);

    83     srand(seed);

    84 #endif

    85 }

    86 }

    87 

    88 #endif