Add boost/core/detail/minstd_rand.hpp

include/boost/core/detail/minstd_rand.hpp

@@ -0,0 +1,58 @@
+#ifndef BOOST_CORE_DETAIL_MINSTD_RAND_HPP_INCLUDED
+#define BOOST_CORE_DETAIL_MINSTD_RAND_HPP_INCLUDED
+
+// Copyright 2017 Peter Dimov
+//
+// 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
+//
+// An implementation of minstd_rand that does not require
+// the Random library
+
+#include <boost/cstdint.hpp>
+
+namespace boost
+{
+namespace detail
+{
+
+class minstd_rand
+{
+private:
+
+    boost::uint_least32_t x_;
+
+    enum { a = 48271, m = 2147483647 };
+
+public:
+
+    minstd_rand(): x_( 1 )
+    {
+    }
+
+    explicit minstd_rand( boost::uint_least32_t x ): x_( x % m )
+    {
+        if( x_ == 0 )
+        {
+            x_ = 1;
+        }
+    }
+
+    boost::uint_least32_t operator()()
+    {
+        boost::uint_least64_t y = x_;
+
+        y = ( a * y ) % m;
+
+        x_ = static_cast<boost::uint_least32_t>( y );
+
+        return x_;
+    }
+};
+
+} // namespace detail
+} // namespace boost
+
+#endif // #ifndef BOOST_CORE_DETAIL_MINSTD_RAND_HPP_INCLUDED

test/Jamfile.v2

@@ -440,5 +440,8 @@ run yield_prim_pthread_cancel_test.cpp : ;
 run pointer_in_range_test.cpp ;
 compile pointer_in_range_constexpr_test.cpp ;
 
+run minstd_rand_test.cpp
+  : : : $(pedantic-errors) ;
+
 use-project /boost/core/swap : ./swap ;
 build-project ./swap ;

test/minstd_rand_test.cpp

@@ -0,0 +1,38 @@
+// Test for boost/core/detail/minstd_rand.hpp
+//
+// Copyright 2022, 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/core/detail/minstd_rand.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/cstdint.hpp>
+
+int main()
+{
+    {
+        boost::detail::minstd_rand rng;
+
+        boost::uint_least32_t r1 = rng(), x1 = 48271;
+        BOOST_TEST_EQ( r1, x1 );
+
+        for( int i = 0; i < 1000; ++i ) rng();
+
+        boost::uint_least32_t r2 = rng(), x2 = 2076422031;
+        BOOST_TEST_EQ( r2, x2 );
+    }
+
+    {
+        boost::detail::minstd_rand rng( 12345 );
+
+        boost::uint_least32_t r1 = rng(), x1 = 595905495;
+        BOOST_TEST_EQ( r1, x1 );
+
+        for( int i = 0; i < 1000; ++i ) rng();
+
+        boost::uint_least32_t r2 = rng(), x2 = 1065162103;
+        BOOST_TEST_EQ( r2, x2 );
+    }
+
+    return boost::report_errors();
+}