#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. */
}