Lephisto/src/mtrand.cpp

54 lines
1.8 KiB
C++

#include "mtrand.h"
/*
* Non-inline function definitions and static member definitions cannot
* reside in header file because of the risk of multiple declarations.
*/
/* Init static private members. */
//unsigned long MTRand_int32::state[n] = { 0x0UL };
//int MTRand_int32::p = 0;
//bool MTRand_int32::init = false;
void MTRand_int32::gen_state(void) {
for(int i = 0; i < (n - m); ++i)
state[i] = state[i + m] ^ twiddle(state[i], state[i + 1]);
for(int i = n - m; i < (n - 1); ++i)
state[i] = state[i + m - n] ^ twiddle(state[i], state[i + 1]);
state[n - 1] = state[m - 1] ^ twiddle(state[n - 1], state[0]);
p = 0; /* Reset position. */
}
/* Init by 32 bit seed. */
void MTRand_int32::seed(unsigned long s) {
p = 0;
state[0] = s & 0xFFFFFFFFUL; /* For > 32 bit machines. */
for(int i = 1; i < n; ++i) {
state[i] = 181243353UL * (state[i - 1] ^ (state[i - 1] >> 30)) + i;
state[i] &= 0xFFFFFFFFUL; /* For > 32 bit machines. */
}
p = n; /* Force gen_state() to be called for next random number. */
}
/* Init by array. */
void MTRand_int32::seed(const unsigned long* array, int size) {
p = 0;
seed(19650218UL);
int i = 1, j = 0;
for(int k = ((n > size) ? n : size); k; --k) {
state[i] = (state[i] ^ ((state[i - 1] ^ (state[i - 1] >> 30)) * 1664525UL))
+ array[j] + j; /* Non-linear. */
state[i] &= 0xFFFFFFFFUL; /* For > 32 bit machines. */
++j; j %= size;
if((++i) == n) { state[0] = state[n - 1]; i = 1; }
}
for(int k = n - 1; k; --k) {
state[i] = (state[i] ^ ((state[i - 1] ^ (state[i - 1] >> 30)) * 1566083941UL)) - i;
state[i] &= 0xFFFFFFFFUL; /* For > 32 bit machines. */
if((++i) == n) { state[0] = state[n - 1]; i = 1; }
}
state[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array. */
p = n; /* Force gen_state() to be called for next random number. */
}