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/*

Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,

All rights reserved.                          

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

modification, are permitted provided that the following conditions

are met:

1. Redistributions of source code must retain the above copyright

notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright

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

documentation and/or other materials provided with the distribution.

3. The names of its contributors may not be used to endorse or promote

products derived from this software without specific prior written

permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

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

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

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

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

LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Any feedback is very welcome.

http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html

email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)

*/

#include <windows.h> 

#include "MTRand.h"

#include "Debug.h"

#include <stdio.h>

using namespace Sexy;

/* Period parameters */  

#define MTRAND_M 397

#define MATRIX_A 0x9908b0dfUL   /* constant vector a */

#define UPPER_MASK 0x80000000UL /* most significant w-r bits */

#define LOWER_MASK 0x7fffffffUL /* least significant r bits */

/* Tempering parameters */  

#define TEMPERING_MASK_B 0x9d2c5680

#define TEMPERING_MASK_C 0xefc60000

#define TEMPERING_SHIFT_U(y)  (y >> 11)

#define TEMPERING_SHIFT_S(y)  (y << 7)

#define TEMPERING_SHIFT_T(y)  (y << 15)

#define TEMPERING_SHIFT_L(y)  (y >> 18)

MTRand::MTRand(const std::string& theSerialData)

{

        SRand(theSerialData);

        mti=MTRAND_N+1; /* mti==MTRAND_N+1 means mt[MTRAND_N] is not initialized */

}

MTRand::MTRand(unsigned long seed)    

{

        SRand(seed);

}

MTRand::MTRand()

{

        SRand(4357);

}

static int gRandAllowed = 0;

void MTRand::SetRandAllowed(bool allowed)

{

        if (allowed)

        {

                if (gRandAllowed>0)

                        gRandAllowed--;

                else

                        DBG_ASSERT(false); // mismatched calls

        }

        else

                gRandAllowed++;

}

void MTRand::SRand(const std::string& theSerialData)

{

        if (theSerialData.size() == MTRAND_N*4)

        {

                memcpy(mt, theSerialData.c_str(), MTRAND_N*4);

        }

        else

                SRand(4357);

}

void MTRand::SRand(unsigned long seed)

{

        if (seed == 0)

                seed = 4357;

        /* setting initial seeds to mt[MTRAND_N] using         */

    /* the generator Line 25 of Table 1 in          */

    /* [KNUTH 1981, The Art of Computer Programming */

    /*    Vol. 2 (2nd Ed.), pp102]                  */

        mt[0]= seed & 0xffffffffUL;

        for (mti=1; mti< MTRAND_N; mti++)

        {

                mt[mti] =

                        (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti);

                /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */

                /* In the previous versions, MSBs of the seed affect   */

                /* only MSBs of the array mt[].                        */

                /* 2002/01/09 modified by Makoto Matsumoto             */

                mt[mti] &= 0xffffffffUL;

                /* for >32 bit machines */

        }

}

unsigned long MTRand::Next()

{

        DBG_ASSERT(gRandAllowed==0);

        return NextNoAssert();

}

unsigned long MTRand::NextNoAssert()

{

    unsigned long y;

    static unsigned long mag01[2]={0x0, MATRIX_A};

    /* mag01[x] = x * MATRIX_A  for x=0,1 */

        if (mti >= MTRAND_N) { /* generate MTRAND_N words at one time */

                int kk;

                for (kk=0;kk<MTRAND_N-MTRAND_M;kk++) {

                        y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);

                        mt[kk] = mt[kk+MTRAND_M] ^ (y >> 1) ^ mag01[y & 0x1UL];

                }

                for (;kk<MTRAND_N-1;kk++) {

                        y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);

                        mt[kk] = mt[kk+(MTRAND_M-MTRAND_N)] ^ (y >> 1) ^ mag01[y & 0x1UL];

                }

                y = (mt[MTRAND_N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);

                mt[MTRAND_N-1] = mt[MTRAND_M-1] ^ (y >> 1) ^ mag01[y & 0x1UL];

                mti = 0;

        }

    y = mt[mti++];

    y ^= TEMPERING_SHIFT_U(y);

    y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B;

    y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C;

    y ^= TEMPERING_SHIFT_L(y);

        y &= 0x7FFFFFFF;               

        /*char aStr[256];

        sprintf(aStr, "Rand=%d\r\n", y);

        OutputDebugString(aStr);*/

    return y;

}

unsigned long MTRand::NextNoAssert(unsigned long range)

{

        return NextNoAssert() % range;

}

unsigned long MTRand::Next(unsigned long range)

{

        DBG_ASSERT(gRandAllowed==0);

        return NextNoAssert( range );

}

float MTRand::NextNoAssert(float range)

{

        return (float) ((double)NextNoAssert() / (double)0x7FFFFFFF * range);

}

float MTRand::Next(float range)

{

        DBG_ASSERT(gRandAllowed==0);

        return NextNoAssert(range);

}

std::string MTRand::Serialize()

{

        std::string aString;

        aString.resize(MTRAND_N*4);

        memcpy((char*) aString.c_str(), mt, MTRAND_N*4);

        return aString;

}