boost/random/xor_combine.hpp
/* boost random/xor_combine.hpp header file
*
* Copyright Jens Maurer 2002
* Permission to use, copy, modify, sell, and distribute this software
* is hereby granted without fee provided that the above copyright notice
* appears in all copies and that both that copyright notice and this
* permission notice appear in supporting documentation,
*
* Jens Maurer makes no representations about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*
* See http://www.boost.org for most recent version including documentation.
*
* $Id: xor_combine.hpp,v 1.6 2003/04/02 23:21:59 jmaurer Exp $
*
*/
#ifndef BOOST_RANDOM_XOR_COMBINE_HPP
#define BOOST_RANDOM_XOR_COMBINE_HPP
#include <iostream>
#include <cassert>
#include <boost/config.hpp>
#include <boost/limits.hpp>
#include <boost/static_assert.hpp>
#include <boost/cstdint.hpp> // uint32_t
namespace boost {
namespace random {
template<class URNG1, int s1, class URNG2, int s2,
#ifndef BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS
typename URNG1::result_type
#else
uint32_t
#endif
val = 0>
class xor_combine
{
public:
typedef URNG1 base1_type;
typedef URNG2 base2_type;
typedef typename base1_type::result_type result_type;
BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
BOOST_STATIC_CONSTANT(int, shift1 = s1);
BOOST_STATIC_CONSTANT(int, shfit2 = s2);
xor_combine() : _rng1(), _rng2()
{ }
xor_combine(const base1_type & rng1, const base2_type & rng2)
: _rng1(rng1), _rng2(rng2) { }
template<class It> xor_combine(It& first, It last)
: _rng1(first, last), _rng2( /* advanced by other call */ first, last) { }
void seed() { _rng1.seed(); _rng2.seed(); }
template<class It> void seed(It& first, It last)
{
_rng1.seed(first, last);
_rng2.seed(first, last);
}
const base1_type& base1() { return _rng1; }
const base2_type& base2() { return _rng2; }
result_type operator()()
{
// MSVC fails BOOST_STATIC_ASSERT with std::numeric_limits at class scope
#if !defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) && !(defined(BOOST_MSVC) && BOOST_MSVC <= 1300)
BOOST_STATIC_ASSERT(std::numeric_limits<typename base1_type::result_type>::is_integer);
BOOST_STATIC_ASSERT(std::numeric_limits<typename base2_type::result_type>::is_integer);
BOOST_STATIC_ASSERT(std::numeric_limits<typename base1_type::result_type>::digits >= std::numeric_limits<typename base2_type::result_type>::digits);
#endif
return (_rng1() << s1) ^ (_rng2() << s2);
}
result_type min() const { return std::min(_rng1.min(), _rng2.min()); }
result_type max() const { return std::max(_rng1.min(), _rng2.max()); }
static bool validation(result_type x) { return val == x; }
#ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
template<class CharT, class Traits>
friend std::basic_ostream<CharT,Traits>&
operator<<(std::basic_ostream<CharT,Traits>& os, const xor_combine& s)
{
os << s._rng1 << " " << s._rng2 << " ";
return os;
}
template<class CharT, class Traits>
friend std::basic_istream<CharT,Traits>&
operator>>(std::basic_istream<CharT,Traits>& is, xor_combine& s)
{
is >> s._rng1 >> std::ws >> s._rng2 >> std::ws;
return is;
}
#endif
friend bool operator==(const xor_combine& x, const xor_combine& y)
{ return x._rng1 == y._rng1 && x._rng2 == y._rng2; }
friend bool operator!=(const xor_combine& x, const xor_combine& y)
{ return !(x == y); }
#else
// Use a member function; Streamable concept not supported.
bool operator==(const xor_combine& rhs) const
{ return _rng1 == rhs._rng1 && _rng2 == rhs._rng2; }
bool operator!=(const xor_combine& rhs) const
{ return !(*this == rhs); }
#endif
private:
base1_type _rng1;
base2_type _rng2;
};
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
// A definition is required even for integral static constants
template<class URNG1, int s1, class URNG2, int s2,
#ifndef BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS
typename URNG1::result_type
#else
uint32_t
#endif
val>
const bool xor_combine<URNG1, s1, URNG2, s2, val>::has_fixed_range;
#endif
} // namespace random
} // namespace boost
#endif // BOOST_RANDOM_XOR_COMBINE_HPP