--- /dev/null
+/* boost random/detail/seed.hpp header file
+ *
+ * Copyright Steven Watanabe 2009
+ * 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: seed_impl.hpp 72951 2011-07-07 04:57:37Z steven_watanabe $
+ */
+
+#ifndef BOOST_RANDOM_DETAIL_SEED_IMPL_HPP
+#define BOOST_RANDOM_DETAIL_SEED_IMPL_HPP
+
+#include <stdexcept>
+#include <boost/cstdint.hpp>
+#include <boost/config/no_tr1/cmath.hpp>
+#include <boost/integer/integer_mask.hpp>
+#include <boost/integer/static_log2.hpp>
+#include <boost/type_traits/is_signed.hpp>
+#include <boost/type_traits/is_integral.hpp>
+#include <boost/type_traits/make_unsigned.hpp>
+#include <boost/mpl/bool.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/mpl/int.hpp>
+#include <boost/random/detail/const_mod.hpp>
+#include <boost/random/detail/integer_log2.hpp>
+#include <boost/random/detail/signed_unsigned_tools.hpp>
+#include <boost/random/detail/generator_bits.hpp>
+
+#include <boost/random/detail/disable_warnings.hpp>
+
+namespace boost {
+namespace random {
+namespace detail {
+
+// finds the seed type of an engine, given its
+// result_type. If the result_type is integral
+// the seed type is the same. If the result_type
+// is floating point, the seed type is uint32_t
+template<class T>
+struct seed_type
+{
+ typedef typename boost::mpl::if_<boost::is_integral<T>,
+ T,
+ boost::uint32_t
+ >::type type;
+};
+
+template<int N>
+struct const_pow_impl
+{
+ template<class T>
+ static T call(T arg, int n, T result)
+ {
+ return const_pow_impl<N / 2>::call(arg * arg, n / 2,
+ n%2 == 0? result : result * arg);
+ }
+};
+
+template<>
+struct const_pow_impl<0>
+{
+ template<class T>
+ static T call(T, int, T result)
+ {
+ return result;
+ }
+};
+
+// requires N is an upper bound on n
+template<int N, class T>
+inline T const_pow(T arg, int n) { return const_pow_impl<N>::call(arg, n, T(1)); }
+
+template<class T>
+inline T pow2(int n)
+{
+ typedef unsigned int_type;
+ const int max_bits = std::numeric_limits<int_type>::digits;
+ T multiplier = T(int_type(1) << (max_bits - 1)) * 2;
+ return (int_type(1) << (n % max_bits)) *
+ const_pow<std::numeric_limits<T>::digits / max_bits>(multiplier, n / max_bits);
+}
+
+template<class Engine, class Iter>
+void generate_from_real(Engine& eng, Iter begin, Iter end)
+{
+ using std::fmod;
+ typedef typename Engine::result_type RealType;
+ const int Bits = detail::generator_bits<Engine>::value();
+ int remaining_bits = 0;
+ boost::uint_least32_t saved_bits = 0;
+ RealType multiplier = pow2<RealType>( Bits);
+ RealType mult32 = RealType(4294967296.0); // 2^32
+ while(true) {
+ RealType val = eng() * multiplier;
+ int available_bits = Bits;
+ // Make sure the compiler can optimize this out
+ // if it isn't possible.
+ if(Bits < 32 && available_bits < 32 - remaining_bits) {
+ saved_bits |= boost::uint_least32_t(val) << remaining_bits;
+ remaining_bits += Bits;
+ } else {
+ // If Bits < 32, then remaining_bits != 0, since
+ // if remaining_bits == 0, available_bits < 32 - 0,
+ // and we won't get here to begin with.
+ if(Bits < 32 || remaining_bits != 0) {
+ boost::uint_least32_t divisor =
+ (boost::uint_least32_t(1) << (32 - remaining_bits));
+ boost::uint_least32_t extra_bits = boost::uint_least32_t(fmod(val, mult32)) & (divisor - 1);
+ val = val / divisor;
+ *begin++ = saved_bits | (extra_bits << remaining_bits);
+ if(begin == end) return;
+ available_bits -= 32 - remaining_bits;
+ remaining_bits = 0;
+ }
+ // If Bits < 32 we should never enter this loop
+ if(Bits >= 32) {
+ for(; available_bits >= 32; available_bits -= 32) {
+ boost::uint_least32_t word = boost::uint_least32_t(fmod(val, mult32));
+ val /= mult32;
+ *begin++ = word;
+ if(begin == end) return;
+ }
+ }
+ remaining_bits = available_bits;
+ saved_bits = static_cast<boost::uint_least32_t>(val);
+ }
+ }
+}
+
+template<class Engine, class Iter>
+void generate_from_int(Engine& eng, Iter begin, Iter end)
+{
+ typedef typename Engine::result_type IntType;
+ typedef typename boost::make_unsigned<IntType>::type unsigned_type;
+ int remaining_bits = 0;
+ boost::uint_least32_t saved_bits = 0;
+ unsigned_type range = boost::random::detail::subtract<IntType>()((eng.max)(), (eng.min)());
+
+ int bits =
+ (range == (std::numeric_limits<unsigned_type>::max)()) ?
+ std::numeric_limits<unsigned_type>::digits :
+ detail::integer_log2(range + 1);
+
+ {
+ int discarded_bits = detail::integer_log2(bits);
+ unsigned_type excess = (range + 1) >> (bits - discarded_bits);
+ if(excess != 0) {
+ int extra_bits = detail::integer_log2((excess - 1) ^ excess);
+ bits = bits - discarded_bits + extra_bits;
+ }
+ }
+
+ unsigned_type mask = (static_cast<unsigned_type>(2) << (bits - 1)) - 1;
+ unsigned_type limit = ((range + 1) & ~mask) - 1;
+
+ while(true) {
+ unsigned_type val;
+ do {
+ val = boost::random::detail::subtract<IntType>()(eng(), (eng.min)());
+ } while(limit != range && val > limit);
+ val &= mask;
+ int available_bits = bits;
+ if(available_bits == 32) {
+ *begin++ = static_cast<boost::uint_least32_t>(val) & 0xFFFFFFFFu;
+ if(begin == end) return;
+ } else if(available_bits % 32 == 0) {
+ for(int i = 0; i < available_bits / 32; ++i) {
+ boost::uint_least32_t word = boost::uint_least32_t(val) & 0xFFFFFFFFu;
+ int supress_warning = (bits >= 32);
+ BOOST_ASSERT(supress_warning == 1);
+ val >>= (32 * supress_warning);
+ *begin++ = word;
+ if(begin == end) return;
+ }
+ } else if(bits < 32 && available_bits < 32 - remaining_bits) {
+ saved_bits |= boost::uint_least32_t(val) << remaining_bits;
+ remaining_bits += bits;
+ } else {
+ if(bits < 32 || remaining_bits != 0) {
+ boost::uint_least32_t extra_bits = boost::uint_least32_t(val) & ((boost::uint_least32_t(1) << (32 - remaining_bits)) - 1);
+ val >>= 32 - remaining_bits;
+ *begin++ = saved_bits | (extra_bits << remaining_bits);
+ if(begin == end) return;
+ available_bits -= 32 - remaining_bits;
+ remaining_bits = 0;
+ }
+ if(bits >= 32) {
+ for(; available_bits >= 32; available_bits -= 32) {
+ boost::uint_least32_t word = boost::uint_least32_t(val) & 0xFFFFFFFFu;
+ int supress_warning = (bits >= 32);
+ BOOST_ASSERT(supress_warning == 1);
+ val >>= (32 * supress_warning);
+ *begin++ = word;
+ if(begin == end) return;
+ }
+ }
+ remaining_bits = available_bits;
+ saved_bits = static_cast<boost::uint_least32_t>(val);
+ }
+ }
+}
+
+template<class Engine, class Iter>
+void generate_impl(Engine& eng, Iter first, Iter last, boost::mpl::true_)
+{
+ return detail::generate_from_int(eng, first, last);
+}
+
+template<class Engine, class Iter>
+void generate_impl(Engine& eng, Iter first, Iter last, boost::mpl::false_)
+{
+ return detail::generate_from_real(eng, first, last);
+}
+
+template<class Engine, class Iter>
+void generate(Engine& eng, Iter first, Iter last)
+{
+ return detail::generate_impl(eng, first, last, boost::is_integral<typename Engine::result_type>());
+}
+
+
+
+template<class IntType, IntType m, class SeedSeq>
+IntType seed_one_int(SeedSeq& seq)
+{
+ static const int log = ::boost::mpl::if_c<(m == 0),
+ ::boost::mpl::int_<(::std::numeric_limits<IntType>::digits)>,
+ ::boost::static_log2<m> >::type::value;
+ static const int k =
+ (log + ((~(static_cast<IntType>(2) << (log - 1)) & m)? 32 : 31)) / 32;
+ ::boost::uint_least32_t array[log / 32 + 4];
+ seq.generate(&array[0], &array[0] + k + 3);
+ IntType s = 0;
+ for(int j = 0; j < k; ++j) {
+ IntType digit = const_mod<IntType, m>::apply(IntType(array[j+3]));
+ IntType mult = IntType(1) << 32*j;
+ s = const_mod<IntType, m>::mult_add(mult, digit, s);
+ }
+ return s;
+}
+
+template<class IntType, IntType m, class Iter>
+IntType get_one_int(Iter& first, Iter last)
+{
+ static const int log = ::boost::mpl::if_c<(m == 0),
+ ::boost::mpl::int_<(::std::numeric_limits<IntType>::digits)>,
+ ::boost::static_log2<m> >::type::value;
+ static const int k =
+ (log + ((~(static_cast<IntType>(2) << (log - 1)) & m)? 32 : 31)) / 32;
+ IntType s = 0;
+ for(int j = 0; j < k; ++j) {
+ if(first == last) {
+ throw ::std::invalid_argument("Not enough elements in call to seed.");
+ }
+ IntType digit = const_mod<IntType, m>::apply(IntType(*first++));
+ IntType mult = IntType(1) << 32*j;
+ s = const_mod<IntType, m>::mult_add(mult, digit, s);
+ }
+ return s;
+}
+
+// TODO: work in-place whenever possible
+template<int w, std::size_t n, class SeedSeq, class UIntType>
+void seed_array_int_impl(SeedSeq& seq, UIntType (&x)[n])
+{
+ boost::uint_least32_t storage[((w+31)/32) * n];
+ seq.generate(&storage[0], &storage[0] + ((w+31)/32) * n);
+ for(std::size_t j = 0; j < n; j++) {
+ UIntType val = 0;
+ for(std::size_t k = 0; k < (w+31)/32; ++k) {
+ val += static_cast<UIntType>(storage[(w+31)/32*j + k]) << 32*k;
+ }
+ x[j] = val & ::boost::low_bits_mask_t<w>::sig_bits;
+ }
+}
+
+template<int w, std::size_t n, class SeedSeq, class IntType>
+inline void seed_array_int_impl(SeedSeq& seq, IntType (&x)[n], boost::mpl::true_)
+{
+ typedef typename boost::make_unsigned<IntType>::type unsigned_array[n];
+ seed_array_int_impl<w>(seq, reinterpret_cast<unsigned_array&>(x));
+}
+
+template<int w, std::size_t n, class SeedSeq, class IntType>
+inline void seed_array_int_impl(SeedSeq& seq, IntType (&x)[n], boost::mpl::false_)
+{
+ seed_array_int_impl<w>(seq, x);
+}
+
+template<int w, std::size_t n, class SeedSeq, class IntType>
+inline void seed_array_int(SeedSeq& seq, IntType (&x)[n])
+{
+ seed_array_int_impl<w>(seq, x, boost::is_signed<IntType>());
+}
+
+template<int w, std::size_t n, class Iter, class UIntType>
+void fill_array_int_impl(Iter& first, Iter last, UIntType (&x)[n])
+{
+ for(std::size_t j = 0; j < n; j++) {
+ UIntType val = 0;
+ for(std::size_t k = 0; k < (w+31)/32; ++k) {
+ if(first == last) {
+ throw std::invalid_argument("Not enough elements in call to seed.");
+ }
+ val += static_cast<UIntType>(*first++) << 32*k;
+ }
+ x[j] = val & ::boost::low_bits_mask_t<w>::sig_bits;
+ }
+}
+
+template<int w, std::size_t n, class Iter, class IntType>
+inline void fill_array_int_impl(Iter& first, Iter last, IntType (&x)[n], boost::mpl::true_)
+{
+ typedef typename boost::make_unsigned<IntType>::type unsigned_array[n];
+ fill_array_int_impl<w>(first, last, reinterpret_cast<unsigned_array&>(x));
+}
+
+template<int w, std::size_t n, class Iter, class IntType>
+inline void fill_array_int_impl(Iter& first, Iter last, IntType (&x)[n], boost::mpl::false_)
+{
+ fill_array_int_impl<w>(first, last, x);
+}
+
+template<int w, std::size_t n, class Iter, class IntType>
+inline void fill_array_int(Iter& first, Iter last, IntType (&x)[n])
+{
+ fill_array_int_impl<w>(first, last, x, boost::is_signed<IntType>());
+}
+
+template<int w, std::size_t n, class RealType>
+void seed_array_real_impl(const boost::uint_least32_t* storage, RealType (&x)[n])
+{
+ boost::uint_least32_t mask = ~((~boost::uint_least32_t(0)) << (w%32));
+ RealType two32 = 4294967296.0;
+ const RealType divisor = RealType(1)/detail::pow2<RealType>(w);
+ unsigned int j;
+ for(j = 0; j < n; ++j) {
+ RealType val = RealType(0);
+ RealType mult = divisor;
+ for(int k = 0; k < w/32; ++k) {
+ val += *storage++ * mult;
+ mult *= two32;
+ }
+ if(mask != 0) {
+ val += (*storage++ & mask) * mult;
+ }
+ BOOST_ASSERT(val >= 0);
+ BOOST_ASSERT(val < 1);
+ x[j] = val;
+ }
+}
+
+template<int w, std::size_t n, class SeedSeq, class RealType>
+void seed_array_real(SeedSeq& seq, RealType (&x)[n])
+{
+ using std::pow;
+ boost::uint_least32_t storage[((w+31)/32) * n];
+ seq.generate(&storage[0], &storage[0] + ((w+31)/32) * n);
+ seed_array_real_impl<w>(storage, x);
+}
+
+template<int w, std::size_t n, class Iter, class RealType>
+void fill_array_real(Iter& first, Iter last, RealType (&x)[n])
+{
+ boost::uint_least32_t mask = ~((~boost::uint_least32_t(0)) << (w%32));
+ RealType two32 = 4294967296.0;
+ const RealType divisor = RealType(1)/detail::pow2<RealType>(w);
+ unsigned int j;
+ for(j = 0; j < n; ++j) {
+ RealType val = RealType(0);
+ RealType mult = divisor;
+ for(int k = 0; k < w/32; ++k, ++first) {
+ if(first == last) throw std::invalid_argument("Not enough elements in call to seed.");
+ val += *first * mult;
+ mult *= two32;
+ }
+ if(mask != 0) {
+ if(first == last) throw std::invalid_argument("Not enough elements in call to seed.");
+ val += (*first & mask) * mult;
+ ++first;
+ }
+ BOOST_ASSERT(val >= 0);
+ BOOST_ASSERT(val < 1);
+ x[j] = val;
+ }
+}
+
+}
+}
+}
+
+#include <boost/random/detail/enable_warnings.hpp>
+
+#endif
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