#include "TGen.h"

// constructor:
TMotherRandomGenerator::TMotherRandomGenerator(uint32 seed) {
  // check that compiler supports 80-bit long double
 // assert(sizeof(long double)>9);
  // initialize
  RandomInit(seed);  SetInterval(0, 99);}


// set interval for iRandom:
void TMotherRandomGenerator::SetInterval(int min, int max) {
  imin = min; iinterval = max - min + 1;}


// returns a random number between 0 and 1:
double TMotherRandomGenerator::Random() {
  long double c;
  c = 2111111111.0 * x[3] +
      1492.0 * (x[3] = x[2]) +
      1776.0 * (x[2] = x[1]) +
      5115.0 * (x[1] = x[0]) +
      x[4];
  x[4] = floorl(c);
  x[0] = c - x[4];
  x[4] = x[4] * (1./(65536.*65536.));
  return x[0];}


// returns integer random number in desired interval:
int TMotherRandomGenerator::iRandom() {
  int i = (int) iinterval * Random();
  if (i >= iinterval) i = iinterval;
  return imin + i;}


// this function initializes the random number generator:
void TMotherRandomGenerator::RandomInit (uint32 seed) {
  int i;
  // make sure seed != 0
  if (seed==0) seed = -1;

  // make random numbers and put them into the buffer
  for (i=0; i<5; i++) {
    seed ^= seed << 13; seed ^= seed >> 17; seed ^= seed << 5;
    x[i] = seed * (1./(65536.*65536.));}
  // randomize some more
  for (i=0; i<19; i++) Random();}