Updated boost to v1.55.0

[rsem.git] / boost / random / seed_seq.hpp

diff --git a/boost/random/seed_seq.hpp b/boost/random/seed_seq.hpp
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+/* boost random/seed_seq.hpp header file
+ *
+ * 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: seed_seq.hpp 85813 2013-09-21 20:17:00Z jewillco $
+ *
+ */
+
+#ifndef BOOST_RANDOM_SEED_SEQ_HPP
+#define BOOST_RANDOM_SEED_SEQ_HPP
+
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/range/begin.hpp>
+#include <boost/range/end.hpp>
+#include <cstddef>
+#include <vector>
+#include <algorithm>
+#include <iterator>
+
+#ifndef BOOST_NO_CXX11_HDR_INITIALIZER_LIST
+#include <initializer_list>
+#endif
+
+namespace boost {
+namespace random {
+
+/**
+ * The class @c seed_seq stores a sequence of 32-bit words
+ * for seeding a \pseudo_random_number_generator.  These
+ * words will be combined to fill the entire state of the
+ * generator.
+ */
+class seed_seq {
+public:
+    typedef boost::uint_least32_t result_type;
+
+    /** Initializes a seed_seq to hold an empty sequence. */
+    seed_seq() {}
+#ifndef BOOST_NO_CXX11_HDR_INITIALIZER_LIST
+    /** Initializes the sequence from an initializer_list. */
+    template<class T>
+    seed_seq(const std::initializer_list<T>& il) : v(il.begin(), il.end()) {}
+#endif
+    /** Initializes the sequence from an iterator range. */
+    template<class Iter>
+    seed_seq(Iter first, Iter last) : v(first, last) {}
+    /** Initializes the sequence from Boost.Range range. */
+    template<class Range>
+    explicit seed_seq(const Range& range)
+      : v(boost::begin(range), boost::end(range)) {}
+
+    /**
+     * Fills a range with 32-bit values based on the stored sequence.
+     *
+     * Requires: Iter must be a Random Access Iterator whose value type
+     * is an unsigned integral type at least 32 bits wide.
+     */
+    template<class Iter>
+    void generate(Iter first, Iter last) const
+    {
+        typedef typename std::iterator_traits<Iter>::value_type value_type;
+        std::fill(first, last, static_cast<value_type>(0x8b8b8b8bu));
+        std::size_t s = v.size();
+        std::size_t n = last - first;
+        std::size_t t =
+            (n >= 623) ? 11 :
+            (n >=  68) ?  7 :
+            (n >=  39) ?  5 :
+            (n >=   7) ?  3 :
+            (n - 1)/2;
+        std::size_t p = (n - t) / 2;
+        std::size_t q = p + t;
+        std::size_t m = (std::max)(s+1, n);
+        value_type mask = 0xffffffffu;
+        for(std::size_t k = 0; k < m; ++k) {
+            value_type r1 =
+                *(first + k%n) ^ *(first + (k+p)%n) ^ *(first + (k+n-1)%n);
+            r1 = r1 ^ (r1 >> 27);
+            r1 = (r1 * 1664525u) & mask;
+            value_type r2 = r1 +
+                ((k == 0) ? s :
+                 (k <= s) ? k % n + v[k - 1] :
+                 (k % n));
+            *(first + (k+p)%n) = (*(first + (k+p)%n) + r1) & mask;
+            *(first + (k+q)%n) = (*(first + (k+q)%n) + r2) & mask;
+            *(first + k%n) = r2;
+        }
+        for(std::size_t k = m; k < m + n; ++k) {
+            value_type r3 =
+                (*(first + k%n) + *(first + (k+p)%n) + *(first + (k+n-1)%n))
+                & mask;
+            r3 = r3 ^ (r3 >> 27);
+            r3 = (r3 * 1566083941u) & mask;
+            value_type r4 = r3 - k%m;
+            *(first + (k+p)%n) ^= r3;
+            *(first + (k+q)%n) ^= r4;
+            *(first + k%n) = r4;
+        }
+    }
+    /** Returns the size of the sequence. */
+    std::size_t size() const { return v.size(); }
+    /** Writes the stored sequence to iter. */
+    template<class Iter>
+    void param(Iter out) { std::copy(v.begin(), v.end(), out); }
+private:
+    std::vector<result_type> v;
+};
+
+}
+}
+
+#endif