/* boost random/discard_block.hpp header file
*
* Copyright Jens Maurer 2002
+ * Copyright Steven Watanabe 2010
* Distributed under the Boost Software License, Version 1.0. (See
* accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* See http://www.boost.org for most recent version including documentation.
*
- * $Id: discard_block.hpp 60755 2010-03-22 00:45:06Z steven_watanabe $
+ * $Id: discard_block.hpp 72951 2011-07-07 04:57:37Z steven_watanabe $
*
* Revision history
* 2001-03-02 created
#include <iostream>
#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
#include <boost/limits.hpp>
#include <boost/static_assert.hpp>
#include <boost/random/detail/config.hpp>
+#include <boost/random/detail/seed.hpp>
namespace boost {
namespace random {
/**
- * The class template \discard_block is a model of
+ * The class template \discard_block_engine is a model of
* \pseudo_random_number_generator. It modifies
* another generator by discarding parts of its output.
- * Out of every block of @c r results, the first @c p
+ * Out of every block of @c p results, the first @c r
* will be returned and the rest discarded.
*
* Requires: 0 < p <= r
*/
-template<class UniformRandomNumberGenerator, unsigned int p, unsigned int r>
-class discard_block
+template<class UniformRandomNumberGenerator, std::size_t p, std::size_t r>
+class discard_block_engine
{
+ typedef typename detail::seed_type<
+ typename UniformRandomNumberGenerator::result_type>::type seed_type;
public:
- typedef UniformRandomNumberGenerator base_type;
- typedef typename base_type::result_type result_type;
+ typedef UniformRandomNumberGenerator base_type;
+ typedef typename base_type::result_type result_type;
- BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
- BOOST_STATIC_CONSTANT(unsigned int, total_block = p);
- BOOST_STATIC_CONSTANT(unsigned int, returned_block = r);
+ BOOST_STATIC_CONSTANT(std::size_t, block_size = p);
+ BOOST_STATIC_CONSTANT(std::size_t, used_block = r);
-#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
- BOOST_STATIC_ASSERT(total_block >= returned_block);
+ BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
+ BOOST_STATIC_CONSTANT(std::size_t, total_block = p);
+ BOOST_STATIC_CONSTANT(std::size_t, returned_block = r);
+
+ BOOST_STATIC_ASSERT(total_block >= returned_block);
+
+ /** Uses the default seed for the base generator. */
+ discard_block_engine() : _rng(), _n(0) { }
+ /** Constructs a new \discard_block_engine with a copy of rng. */
+ explicit discard_block_engine(const base_type & rng) : _rng(rng), _n(0) { }
+
+#ifndef BOOST_NO_RVALUE_REFERENCES
+ /** Constructs a new \discard_block_engine with rng. */
+ explicit discard_block_engine(base_type && rng) : _rng(rng), _n(0) { }
#endif
- discard_block() : _rng(), _n(0) { }
- explicit discard_block(const base_type & rng) : _rng(rng), _n(0) { }
- template<class T> explicit discard_block(T s) : _rng(s), _n(0) {}
- template<class It> discard_block(It& first, It last)
- : _rng(first, last), _n(0) { }
- void seed() { _rng.seed(); _n = 0; }
- template<class T> void seed(T s) { _rng.seed(s); _n = 0; }
- template<class It> void seed(It& first, It last)
- { _n = 0; _rng.seed(first, last); }
-
- const base_type& base() const { return _rng; }
-
- result_type operator()()
- {
- if(_n >= returned_block) {
- // discard values of random number generator
- for( ; _n < total_block; ++_n)
- _rng();
- _n = 0;
+ /**
+ * Creates a new \discard_block_engine and seeds the underlying
+ * generator with @c value
+ */
+ BOOST_RANDOM_DETAIL_ARITHMETIC_CONSTRUCTOR(discard_block_engine,
+ seed_type, value)
+ { _rng.seed(value); _n = 0; }
+
+ /**
+ * Creates a new \discard_block_engine and seeds the underlying
+ * generator with @c seq
+ */
+ BOOST_RANDOM_DETAIL_SEED_SEQ_CONSTRUCTOR(discard_block_engine, SeedSeq, seq)
+ { _rng.seed(seq); _n = 0; }
+
+ /**
+ * Creates a new \discard_block_engine and seeds the underlying
+ * generator with first and last.
+ */
+ template<class It> discard_block_engine(It& first, It last)
+ : _rng(first, last), _n(0) { }
+
+ /** default seeds the underlying generator. */
+ void seed() { _rng.seed(); _n = 0; }
+ /** Seeds the underlying generator with s. */
+ BOOST_RANDOM_DETAIL_ARITHMETIC_SEED(discard_block_engine, seed_type, s)
+ { _rng.seed(s); _n = 0; }
+ /** Seeds the underlying generator with seq. */
+ BOOST_RANDOM_DETAIL_SEED_SEQ_SEED(discard_block_engine, SeedSeq, seq)
+ { _rng.seed(seq); _n = 0; }
+ /** Seeds the underlying generator with first and last. */
+ template<class It> void seed(It& first, It last)
+ { _rng.seed(first, last); _n = 0; }
+
+ /** Returns the underlying engine. */
+ const base_type& base() const { return _rng; }
+
+ /** Returns the next value of the generator. */
+ result_type operator()()
+ {
+ if(_n >= returned_block) {
+ // discard values of random number generator
+ // Don't use discard, since we still need to
+ // be somewhat compatible with TR1.
+ // _rng.discard(total_block - _n);
+ for(std::size_t i = 0; i < total_block - _n; ++i) {
+ _rng();
+ }
+ _n = 0;
+ }
+ ++_n;
+ return _rng();
}
- ++_n;
- return _rng();
- }
- 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 true; } // dummy
+ void discard(boost::uintmax_t z)
+ {
+ for(boost::uintmax_t j = 0; j < z; ++j) {
+ (*this)();
+ }
+ }
-#ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
+ template<class It>
+ void generate(It first, It last)
+ { detail::generate(*this, first, last); }
+
+ /**
+ * Returns the smallest value that the generator can produce.
+ * This is the same as the minimum of the underlying generator.
+ */
+ static result_type min BOOST_PREVENT_MACRO_SUBSTITUTION ()
+ { return (base_type::min)(); }
+ /**
+ * Returns the largest value that the generator can produce.
+ * This is the same as the maximum of the underlying generator.
+ */
+ static result_type max BOOST_PREVENT_MACRO_SUBSTITUTION ()
+ { return (base_type::max)(); }
#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 discard_block& s)
- {
- os << s._rng << " " << s._n << " ";
- return os;
- }
-
- template<class CharT, class Traits>
- friend std::basic_istream<CharT,Traits>&
- operator>>(std::basic_istream<CharT,Traits>& is, discard_block& s)
- {
- is >> s._rng >> std::ws >> s._n >> std::ws;
- return is;
- }
-#endif
+ /** Writes a \discard_block_engine to a @c std::ostream. */
+ template<class CharT, class Traits>
+ friend std::basic_ostream<CharT,Traits>&
+ operator<<(std::basic_ostream<CharT,Traits>& os,
+ const discard_block_engine& s)
+ {
+ os << s._rng << ' ' << s._n;
+ return os;
+ }
- friend bool operator==(const discard_block& x, const discard_block& y)
- { return x._rng == y._rng && x._n == y._n; }
- friend bool operator!=(const discard_block& x, const discard_block& y)
- { return !(x == y); }
-#else
- // Use a member function; Streamable concept not supported.
- bool operator==(const discard_block& rhs) const
- { return _rng == rhs._rng && _n == rhs._n; }
- bool operator!=(const discard_block& rhs) const
- { return !(*this == rhs); }
+ /** Reads a \discard_block_engine from a @c std::istream. */
+ template<class CharT, class Traits>
+ friend std::basic_istream<CharT,Traits>&
+ operator>>(std::basic_istream<CharT,Traits>& is, discard_block_engine& s)
+ {
+ is >> s._rng >> std::ws >> s._n;
+ return is;
+ }
#endif
+ /** Returns true if the two generators will produce identical sequences. */
+ friend bool operator==(const discard_block_engine& x,
+ const discard_block_engine& y)
+ { return x._rng == y._rng && x._n == y._n; }
+ /** Returns true if the two generators will produce different sequences. */
+ friend bool operator!=(const discard_block_engine& x,
+ const discard_block_engine& y)
+ { return !(x == y); }
+
private:
- base_type _rng;
- unsigned int _n;
+ base_type _rng;
+ std::size_t _n;
};
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
// A definition is required even for integral static constants
-template<class UniformRandomNumberGenerator, unsigned int p, unsigned int r>
-const bool discard_block<UniformRandomNumberGenerator, p, r>::has_fixed_range;
-template<class UniformRandomNumberGenerator, unsigned int p, unsigned int r>
-const unsigned int discard_block<UniformRandomNumberGenerator, p, r>::total_block;
-template<class UniformRandomNumberGenerator, unsigned int p, unsigned int r>
-const unsigned int discard_block<UniformRandomNumberGenerator, p, r>::returned_block;
+template<class URNG, std::size_t p, std::size_t r>
+const bool discard_block_engine<URNG, p, r>::has_fixed_range;
+template<class URNG, std::size_t p, std::size_t r>
+const std::size_t discard_block_engine<URNG, p, r>::total_block;
+template<class URNG, std::size_t p, std::size_t r>
+const std::size_t discard_block_engine<URNG, p, r>::returned_block;
+template<class URNG, std::size_t p, std::size_t r>
+const std::size_t discard_block_engine<URNG, p, r>::block_size;
+template<class URNG, std::size_t p, std::size_t r>
+const std::size_t discard_block_engine<URNG, p, r>::used_block;
#endif
+/// \cond \show_deprecated
+
+template<class URNG, int p, int r>
+class discard_block : public discard_block_engine<URNG, p, r>
+{
+ typedef discard_block_engine<URNG, p, r> base_t;
+public:
+ typedef typename base_t::result_type result_type;
+ discard_block() {}
+ template<class T>
+ discard_block(T& arg) : base_t(arg) {}
+ template<class T>
+ discard_block(const T& arg) : base_t(arg) {}
+ template<class It>
+ discard_block(It& first, It last) : base_t(first, last) {}
+ result_type min BOOST_PREVENT_MACRO_SUBSTITUTION ()
+ { return (this->base().min)(); }
+ result_type max BOOST_PREVENT_MACRO_SUBSTITUTION ()
+ { return (this->base().max)(); }
+};
+
+/// \endcond
+
+namespace detail {
+
+ template<class Engine>
+ struct generator_bits;
+
+ template<class URNG, std::size_t p, std::size_t r>
+ struct generator_bits<discard_block_engine<URNG, p, r> > {
+ static std::size_t value() { return generator_bits<URNG>::value(); }
+ };
+
+ template<class URNG, int p, int r>
+ struct generator_bits<discard_block<URNG, p, r> > {
+ static std::size_t value() { return generator_bits<URNG>::value(); }
+ };
+
+}
+
} // namespace random
} // namespace boost
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