From fbc198e75d38f8d8fe2f964cd4be8055c8c5b6d6 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Sun, 20 Oct 2019 21:28:38 +0300
Subject: [PATCH] Add __int128 support to endian_reverse

---
 .../boost/endian/detail/endian_reverse.hpp    | 14 +++-
 .../boost/endian/detail/integral_by_size.hpp  | 10 +++
 test/endian_reverse_test.cpp                  | 67 +++++++++++++++++++
 3 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/include/boost/endian/detail/endian_reverse.hpp b/include/boost/endian/detail/endian_reverse.hpp
index 5761b2c..4fd71bb 100644
--- a/include/boost/endian/detail/endian_reverse.hpp
+++ b/include/boost/endian/detail/endian_reverse.hpp
@@ -62,7 +62,7 @@ inline uint16_t BOOST_ENDIAN_CONSTEXPR endian_reverse_impl( uint16_t x ) BOOST_N
 #endif
 }
 
-inline uint32_t BOOST_ENDIAN_CONSTEXPR endian_reverse_impl(uint32_t x) BOOST_NOEXCEPT
+inline uint32_t BOOST_ENDIAN_CONSTEXPR endian_reverse_impl( uint32_t x ) BOOST_NOEXCEPT
 {
 #ifdef BOOST_ENDIAN_NO_INTRINSICS
 
@@ -76,7 +76,7 @@ inline uint32_t BOOST_ENDIAN_CONSTEXPR endian_reverse_impl(uint32_t x) BOOST_NOE
 #endif
 }
 
-inline uint64_t BOOST_ENDIAN_CONSTEXPR endian_reverse_impl(uint64_t x) BOOST_NOEXCEPT
+inline uint64_t BOOST_ENDIAN_CONSTEXPR endian_reverse_impl( uint64_t x ) BOOST_NOEXCEPT
 {
 #ifdef BOOST_ENDIAN_NO_INTRINSICS
 
@@ -91,6 +91,16 @@ inline uint64_t BOOST_ENDIAN_CONSTEXPR endian_reverse_impl(uint64_t x) BOOST_NOE
 # endif
 }
 
+#if defined(BOOST_HAS_INT128)
+
+inline uint128_type BOOST_ENDIAN_CONSTEXPR endian_reverse_impl( uint128_type x ) BOOST_NOEXCEPT
+{
+    return endian_reverse_impl( static_cast<uint64_t>( x >> 64 ) ) |
+        static_cast<uint128_type>( endian_reverse_impl( static_cast<uint64_t>( x ) ) ) << 64;
+}
+
+#endif
+
 } // namespace detail
 
 // Requires:
diff --git a/include/boost/endian/detail/integral_by_size.hpp b/include/boost/endian/detail/integral_by_size.hpp
index b0fd885..d53ee17 100644
--- a/include/boost/endian/detail/integral_by_size.hpp
+++ b/include/boost/endian/detail/integral_by_size.hpp
@@ -7,6 +7,7 @@
 // http://www.boost.org/LICENSE_1_0.txt
 
 #include <boost/cstdint.hpp>
+#include <boost/config.hpp>
 #include <cstddef>
 
 namespace boost
@@ -40,6 +41,15 @@ template<> struct integral_by_size<8>
     typedef uint64_t type;
 };
 
+#if defined(BOOST_HAS_INT128)
+
+template<> struct integral_by_size<16>
+{
+    typedef uint128_type type;
+};
+
+#endif
+
 } // namespace detail
 } // namespace endian
 } // namespace boost
diff --git a/test/endian_reverse_test.cpp b/test/endian_reverse_test.cpp
index 9dbba16..fa0f907 100644
--- a/test/endian_reverse_test.cpp
+++ b/test/endian_reverse_test.cpp
@@ -72,6 +72,24 @@ template<class T> T const test_value<T, 8>::w1;
 template<class T> T const test_value<T, 8>::v2;
 template<class T> T const test_value<T, 8>::w2;
 
+#if defined(BOOST_HAS_INT128)
+
+template<class T> struct test_value<T, 16>
+{
+    static const T v1 = static_cast<T>( 0x1F2E3D4C5B6A7988ull ) << 64 | static_cast<T>( 0xF1E2D3C4B5A69780ull );
+    static const T w1 = static_cast<T>( 0x8097A6B5C4D3E2F1ull ) << 64 | static_cast<T>( 0x88796A5B4C3D2E1Full );
+
+    static const T v2 = static_cast<T>( 0xF1E2D3C4B5A69788ull ) << 64 | static_cast<T>( 0x1F2E3D4C5B6A7980ull );
+    static const T w2 = static_cast<T>( 0x80796A5B4C3D2E1Full ) << 64 | static_cast<T>( 0x8897A6B5C4D3E2F1ull );
+};
+
+template<class T> T const test_value<T, 16>::v1;
+template<class T> T const test_value<T, 16>::w1;
+template<class T> T const test_value<T, 16>::v2;
+template<class T> T const test_value<T, 16>::w2;
+
+#endif // #if defined(BOOST_HAS_INT128)
+
 template<class T> void test()
 {
     using boost::endian::endian_reverse;
@@ -114,6 +132,48 @@ template<class T> void test()
     }
 }
 
+template<class T> void test_np()
+{
+    using boost::endian::endian_reverse;
+    using boost::endian::endian_reverse_inplace;
+
+    {
+        T t1 = test_value<T>::v1;
+
+        T t2 = endian_reverse( t1 );
+        BOOST_TEST( t2 == test_value<T>::w1 );
+
+        T t3 = endian_reverse( t2 );
+        BOOST_TEST( t3 == t1 );
+
+        T t4 = t1;
+
+        endian_reverse_inplace( t4 );
+        BOOST_TEST( t4 == test_value<T>::w1 );
+
+        endian_reverse_inplace( t4 );
+        BOOST_TEST( t4 == t1 );
+    }
+
+    {
+        T t1 = test_value<T>::v2;
+
+        T t2 = endian_reverse( t1 );
+        BOOST_TEST( t2 == test_value<T>::w2 );
+
+        T t3 = endian_reverse( t2 );
+        BOOST_TEST( t3 == t1 );
+
+        T t4 = t1;
+
+        endian_reverse_inplace( t4 );
+        BOOST_TEST( t4 == test_value<T>::w2 );
+
+        endian_reverse_inplace( t4 );
+        BOOST_TEST( t4 == t1 );
+    }
+}
+
 int main()
 {
     test<boost::int8_t>();
@@ -152,5 +212,12 @@ int main()
     test<char32_t>();
 #endif
 
+#if defined(BOOST_HAS_INT128)
+
+    test_np<boost::int128_type>();
+    test_np<boost::uint128_type>();
+
+#endif
+
     return boost::report_errors();
 }