1

/* $Id$ */

     2

     3

/** @file random_func.cpp */

     4

     5

#include "../stdafx.h"

     6

#include "random_func.hpp"

     7

#include "bitmath_func.hpp"

     8

     9

Randomizer _random, _interactive_random;

    10

    11

uint32 Randomizer::Next()

    12

{

    13

	const uint32 s = this->state[0];

    14

	const uint32 t = this->state[1];

    15

    16

	this->state[0] = s + ROR(t ^ 0x1234567F, 7) + 1;

    17

	return this->state[1] = ROR(s, 3) - 1;

    18

}

    19

    20

uint32 Randomizer::Next(uint16 max)

    21

{

    22

	return GB(this->Next(), 0, 16) * max >> 16;

    23

}

    24

    25

void Randomizer::SetSeed(uint32 seed)

    26

{

    27

	this->state[0] = seed;

    28

	this->state[1] = seed;

    29

}

    30

    31

#ifdef MERSENNE_TWISTER

    32

// Source code for Mersenne Twister.

    33

// A Random number generator with much higher quality random numbers.

    34

    35

#define N              (624)                 // length of _mt_state vector

    36

#define M              (397)                 // a period parameter

    37

#define K              (0x9908B0DFU)         // a magic constant

    38

#define hiBit(u)       ((u) & 0x80000000U)   // mask all but highest   bit of u

    39

#define loBit(u)       ((u) & 0x00000001U)   // mask all but lowest    bit of u

    40

#define loBits(u)      ((u) & 0x7FFFFFFFU)   // mask     the highest   bit of u

    41

#define mixBits(u, v)  (hiBit(u)|loBits(v))  // move hi bit of u to hi bit of v

    42

    43

static uint32 _mt_state[N+1];     // _mt_state vector + 1 extra to not violate ANSI C

    44

static uint32 *_mt_next;          // _mt_next random value is computed from here

    45

static int    _mt_left = -1;      // can *_mt_next++ this many times before reloading

    46

    47

void SetRandomSeed(register uint32 seed)

    48

{

    49

	register uint32 *s = _mt_state;

    50

	_mt_left = 0;

    51

    52

	seed |= 1U;

    53

	seed &= 0xFFFFFFFFU;

    54

    55

	*s = seed;

    56

    57

	for (register uint i = N; i != 0; i--) {

    58

		seed *= 69069U;

    59

		*s++;

    60

		*s = seed & 0xFFFFFFFFU;

    61

	}

    62

}

    63

    64

static uint32 ReloadRandom()

    65

{

    66

	if (_mt_left < -1) SetRandomSeed(4357U);

    67

    68

	_mt_left = N - 1;

    69

	_mt_next = _mt_state + 1;

    70

    71

	register uint32 *p0 = _mt_state;

    72

	register uint32 *p2 = _mt_state + 2;

    73

	register uint32 *pM = _mt_state + M;

    74

    75

	register uint32 s0 = _mt_state[0];

    76

	register uint32 s1 = _mt_state[1];

    77

    78

	register uint i = 0;

    79

    80

	for (i = (N - M + 1); i != 0; i--) {

    81

		s0 = s1;

    82

		s1 = *p2;

    83

		*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);

    84

		*p0++;

    85

		*p2++;

    86

		*pM++;

    87

	}

    88

    89

	pM = _mt_state;

    90

    91

	for (i = M; i != 0; i--) {

    92

		s0 = s1;

    93

		s1 = *p2;

    94

		*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);

    95

		*p0++;

    96

		*p2++;

    97

		*pM++;

    98

	}

    99

   100

	s1 = _mt_state[0];

   101

	*p0 = *pM ^ (mixBits(s0, s1) >> 1) ^ (loBit(s1) ? K : 0U);

   102

   103

	s1 ^= (s1 >> 11);

   104

	s1 ^= (s1 <<  7) & 0x9D2C5680U;

   105

	s1 ^= (s1 << 15) & 0xEFC60000U;

   106

	s1 ^= (s1 >> 18);

   107

	return s1;

   108

}

   109

   110

uint32 Random()

   111

{

   112

	_mt_left--;

   113

	if (_mt_left < 0) return ReloadRandom();

   114

   115

	uint32 y = *_mt_next;

   116

	*_mt_next++;

   117

   118

	y ^= (y >> 11);

   119

	y ^= (y <<  7) & 0x9D2C5680U;

   120

	y ^= (y << 15) & 0xEFC60000U;

   121

	y ^= (y >> 18);

   122

	return y;

   123

}

   124

   125

#else /* MERSENNE_TWISTER */

   126

void SetRandomSeed(uint32 seed)

   127

{

   128

	_random.SetSeed(seed);

   129

	_interactive_random.SetSeed(seed * 0x1234567);

   130

}

   131

   132

#ifdef RANDOM_DEBUG

   133

#include "../network/network_data.h"

   134

#include "../variables.h" /* _frame_counter */

   135

#include "../player_func.h"

   136

   137

uint32 DoRandom(int line, const char *file)

   138

{

   139

	if (_networking && (DEREF_CLIENT(0)->status != STATUS_INACTIVE || !_network_server)) {

   140

		printf("Random [%d/%d] %s:%d\n",_frame_counter, (byte)_current_player, file, line);

   141

	}

   142

   143

	return _random.Next();

   144

}

   145

#endif /* RANDOM_DEBUG */

   146

#endif /* MERSENNE_TWISTER */

   147

   148

#if defined(RANDOM_DEBUG) && !defined(MERSENNE_TWISTER)

   149

uint DoRandomRange(uint max, int line, const char *file)

   150

{

   151

	return GB(DoRandom(line, file), 0, 16) * max >> 16;

   152

}

   153

#endif /* RANDOM_DEBUG & !MERSENNE_TWISTER */