- typedef UniformRandomNumberGenerator base_type;
- typedef typename base_type::result_type result_type;
-
- BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
- BOOST_STATIC_CONSTANT(int, buffer_size = k);
-
- /**
- * Constructs a @c shuffle_output generator by invoking the
- * default constructor of the base generator.
- *
- * Complexity: Exactly k+1 invocations of the base generator.
- */
- shuffle_output() : _rng() { init(); }
-#if defined(BOOST_MSVC) && _MSC_VER < 1300
- // MSVC does not implicitly generate the copy constructor here
- shuffle_output(const shuffle_output & x)
- : _rng(x._rng), y(x.y) { std::copy(x.v, x.v+k, v); }
-#endif
- /**
- * Constructs a shuffle_output generator by invoking the one-argument
- * constructor of the base generator with the parameter seed.
- *
- * Complexity: Exactly k+1 invocations of the base generator.
- */
- template<class T>
- explicit shuffle_output(T s) : _rng(s) { init(); }
- /**
- * Constructs a shuffle_output generator by using a copy
- * of the provided generator.
- *
- * Precondition: The template argument UniformRandomNumberGenerator
- * shall denote a CopyConstructible type.
- *
- * Complexity: Exactly k+1 invocations of the base generator.
- */
- explicit shuffle_output(const base_type & rng) : _rng(rng) { init(); }
- template<class It> shuffle_output(It& first, It last)
- : _rng(first, last) { init(); }
- void seed() { _rng.seed(); init(); }
- /**
- * Invokes the one-argument seed method of the base generator
- * with the parameter seed and re-initializes the internal buffer array.
- *
- * Complexity: Exactly k+1 invocations of the base generator.
- */
- template<class T>
- void seed(T s) { _rng.seed(s); init(); }
- template<class It> void seed(It& first, It last)
- {
- _rng.seed(first, last);
- init();
- }
-
- const base_type& base() const { return _rng; }
-
- result_type operator()() {
- // calculating the range every time may seem wasteful. However, this
- // makes the information locally available for the optimizer.
- result_type range = (max)()-(min)()+1;
- int j = k*(y-(min)())/range;
- // assert(0 <= j && j < k);
- y = v[j];
- v[j] = _rng();
- return y;
- }
-
- result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (_rng.min)(); }
- result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return (_rng.max)(); }
- static bool validation(result_type x) { return val == x; }
-
-#ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
-
-#ifndef BOOST_RANDOM_NO_STREAM_OPERATORS
- template<class CharT, class Traits>
- friend std::basic_ostream<CharT,Traits>&
- operator<<(std::basic_ostream<CharT,Traits>& os, const shuffle_output& s)
- {
- os << s._rng << " " << s.y << " ";
- for(int i = 0; i < s.buffer_size; ++i)
- os << s.v[i] << " ";
- return os;
- }
-
- template<class CharT, class Traits>
- friend std::basic_istream<CharT,Traits>&
- operator>>(std::basic_istream<CharT,Traits>& is, shuffle_output& s)
- {
- is >> s._rng >> std::ws >> s.y >> std::ws;
- for(int i = 0; i < s.buffer_size; ++i)
- is >> s.v[i] >> std::ws;
- return is;
- }
-#endif
-
- friend bool operator==(const shuffle_output& x, const shuffle_output& y)
- { return x._rng == y._rng && x.y == y.y && std::equal(x.v, x.v+k, y.v); }
- friend bool operator!=(const shuffle_output& x, const shuffle_output& y)
- { return !(x == y); }
-#else
- // Use a member function; Streamable concept not supported.
- bool operator==(const shuffle_output& rhs) const
- { return _rng == rhs._rng && y == rhs.y && std::equal(v, v+k, rhs.v); }
- bool operator!=(const shuffle_output& rhs) const
- { return !(*this == rhs); }
-#endif
-private:
- void init()
- {
-#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
- BOOST_STATIC_ASSERT(std::numeric_limits<result_type>::is_integer);
-#endif
- result_type range = (max)()-(min)();
- assert(range > 0); // otherwise there would be little choice
- if(static_cast<unsigned long>(k * range) <
- static_cast<unsigned long>(range)) // not a sufficient condition
- // likely overflow with bucket number computation
- assert(!"overflow will occur");
-
- // we cannot use std::generate, because it uses pass-by-value for _rng
- for(result_type * p = v; p != v+k; ++p)
- *p = _rng();
- y = _rng();
- }
-
- base_type _rng;
- result_type v[k];
- result_type y;