Add test/get_integral_result_4.cpp

test/Jamfile

@@ -35,6 +35,7 @@ run has_constant_size.cpp ;
 run get_integral_result.cpp ;
 run get_integral_result_2.cpp ;
 run get_integral_result_3.cpp ;
+run get_integral_result_4.cpp ;
 
 # digest
 

test/get_integral_result_4.cpp

@@ -0,0 +1,86 @@
+// Copyright 2017, 2018, 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/hash2/get_integral_result.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <set>
+#include <limits>
+#include <cstdint>
+
+template<class T> void test_identity()
+{
+    using boost::hash2::get_integral_result;
+
+    using R = T;
+
+    for( unsigned i = 0; i <= std::numeric_limits<T>::max(); ++i )
+    {
+        R r = static_cast<R>( i );
+        T t = get_integral_result<T>( r );
+
+        BOOST_TEST_EQ( t, r );
+    }
+}
+
+template<class T, class R> void test_permutation( R offset = 0, R scale = 1 )
+{
+    using boost::hash2::get_integral_result;
+
+    std::set<T> dist;
+
+    for( unsigned i = 0; i <= std::numeric_limits<T>::max(); ++i )
+    {
+        R r = static_cast<R>( i * scale + offset );
+        T t = get_integral_result<T>( r );
+
+        dist.insert( t );
+    }
+
+    BOOST_TEST_EQ( dist.size(), std::numeric_limits<T>::max() + 1u );
+}
+
+template<class T, class R> void test_roundtrip()
+{
+    using boost::hash2::get_integral_result;
+
+    std::set<T> dist;
+
+    for( unsigned i = 0; i <= std::numeric_limits<T>::max(); ++i )
+    {
+        T t1 = static_cast<T>( i );
+        R r = get_integral_result<R>( t1 );
+        T t2 = get_integral_result<T>( r );
+
+        dist.insert( t2 );
+    }
+
+    BOOST_TEST_EQ( dist.size(), std::numeric_limits<T>::max() + 1u );
+}
+
+int main()
+{
+    test_identity<std::uint8_t>();
+
+    test_permutation<std::uint8_t, std::uint8_t>();
+    test_permutation<std::uint8_t, std::uint16_t>();
+    test_permutation<std::uint8_t, std::uint32_t>();
+    test_permutation<std::uint8_t, std::uint64_t>();
+
+    test_roundtrip<std::uint8_t, std::uint8_t>();
+    test_roundtrip<std::uint8_t, std::uint16_t>();
+    test_roundtrip<std::uint8_t, std::uint32_t>();
+    test_roundtrip<std::uint8_t, std::uint64_t>();
+
+    test_identity<std::uint16_t>();
+
+    test_permutation<std::uint16_t, std::uint16_t>();
+    test_permutation<std::uint16_t, std::uint32_t>();
+    test_permutation<std::uint16_t, std::uint64_t>();
+
+    test_roundtrip<std::uint16_t, std::uint16_t>();
+    test_roundtrip<std::uint16_t, std::uint32_t>();
+    test_roundtrip<std::uint16_t, std::uint64_t>();
+
+    return boost::report_errors();
+}