Random.cpp

/*	
 * File: Random.cpp
 * Project: DUtils library
 * Author: Dorian Galvez-Lopez
 * Date: April 2010
 * Description: manages pseudo-random numbers
 * License: see the LICENSE.txt file
 *
 */

#include "Random.h"
#include <cstdlib>
#include <chrono>

using namespace std;

namespace utils{

bool Random::m_already_seeded = false;


void Random::SeedRand() {
    auto now = std::chrono::high_resolution_clock::now();
    auto duration = now.time_since_epoch();
    unsigned seed = static_cast<unsigned>(std::chrono::duration_cast<std::chrono::microseconds>(duration).count());
    srand(seed);
}

void Random::SeedRandOnce()
{
  if(!m_already_seeded)
  {
    Random::SeedRand();
    m_already_seeded = true;
  }
}

void Random::SeedRand(int seed)
{
	srand(seed); 
}

void Random::SeedRandOnce(int seed)
{
  if(!m_already_seeded)
  {
    Random::SeedRand(seed);
    m_already_seeded = true;
  }
}

int Random::RandomInt(int min, int max){
	int d = max - min + 1;
	return int(((double)rand()/((double)RAND_MAX + 1.0)) * d) + min;
}

// ---------------------------------------------------------------------------
// ---------------------------------------------------------------------------

Random::UnrepeatedRandomizer::UnrepeatedRandomizer(int min, int max)
{
  if(min <= max)
  {
    m_min = min;
    m_max = max;
  }
  else
  {
    m_min = max;
    m_max = min;
  }

  createValues();
}

// ---------------------------------------------------------------------------

Random::UnrepeatedRandomizer::UnrepeatedRandomizer
  (const Random::UnrepeatedRandomizer& rnd)
{
  *this = rnd;
}

// ---------------------------------------------------------------------------

int Random::UnrepeatedRandomizer::get()
{
  if(empty()) createValues();
  
  Random::SeedRandOnce();
  
  int k = Random::RandomInt(0, m_values.size()-1);
  int ret = m_values[k];
  m_values[k] = m_values.back();
  m_values.pop_back();
  
  return ret;
}

// ---------------------------------------------------------------------------

void Random::UnrepeatedRandomizer::createValues()
{
  int n = m_max - m_min + 1;
  
  m_values.resize(n);
  for(int i = 0; i < n; ++i) m_values[i] = m_min + i;
}

// ---------------------------------------------------------------------------

void Random::UnrepeatedRandomizer::reset()
{
  if((int)m_values.size() != m_max - m_min + 1) createValues();
}

// ---------------------------------------------------------------------------

Random::UnrepeatedRandomizer& 
Random::UnrepeatedRandomizer::operator=
  (const Random::UnrepeatedRandomizer& rnd)
{
  if(this != &rnd)
  {
    this->m_min = rnd.m_min;
    this->m_max = rnd.m_max;
    this->m_values = rnd.m_values;
  }
  return *this;
}

// ---------------------------------------------------------------------------


}