From b201ff97a8bb9f2b6bd6bb95f3a42c0a47a12f03 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Sat, 16 Oct 2021 16:43:11 +0300
Subject: [PATCH] Use Config macros for detecting C++17 headers

---
 include/boost/container_hash/hash.hpp | 82 +++++++--------------------
 test/hash_info.cpp                    | 45 ++++++++-------
 test/hash_optional_test.cpp           |  4 +-
 test/hash_string_test.cpp             |  2 +-
 test/hash_variant_test.cpp            |  4 +-
 5 files changed, 50 insertions(+), 87 deletions(-)

diff --git a/include/boost/container_hash/hash.hpp b/include/boost/container_hash/hash.hpp
index 98887ae..5fa8e2e 100644
--- a/include/boost/container_hash/hash.hpp
+++ b/include/boost/container_hash/hash.hpp
@@ -36,6 +36,18 @@
 #include <system_error>
 #endif
 
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
+#include <string_view>
+#endif
+
+#if !defined(BOOST_NO_CXX17_HDR_OPTIONAL)
+#include <optional>
+#endif
+
+#if !defined(BOOST_NO_CXX17_HDR_VARIANT)
+#include <variant>
+#endif
+
 #if defined(BOOST_MSVC)
 #pragma warning(push)
 
@@ -53,58 +65,6 @@
 #   define BOOST_FUNCTIONAL_HASH_ROTL32(x, r) (x << r) | (x >> (32 - r))
 #endif
 
-// Detect whether standard library has C++17 headers
-
-#if !defined(BOOST_HASH_CXX17)
-#   if defined(BOOST_MSVC)
-#       if defined(_HAS_CXX17) && _HAS_CXX17
-#           define BOOST_HASH_CXX17 1
-#       endif
-#   elif defined(__cplusplus) && __cplusplus >= 201703
-#       define BOOST_HASH_CXX17 1
-#   endif
-#endif
-
-#if !defined(BOOST_HASH_CXX17)
-#   define BOOST_HASH_CXX17 0
-#endif
-
-#if BOOST_HASH_CXX17 && defined(__has_include)
-#   if !defined(BOOST_HASH_HAS_STRING_VIEW) && __has_include(<string_view>)
-#       define BOOST_HASH_HAS_STRING_VIEW 1
-#   endif
-#   if !defined(BOOST_HASH_HAS_OPTIONAL) && __has_include(<optional>)
-#       define BOOST_HASH_HAS_OPTIONAL 1
-#   endif
-#   if !defined(BOOST_HASH_HAS_VARIANT) && __has_include(<variant>)
-#       define BOOST_HASH_HAS_VARIANT 1
-#   endif
-#endif
-
-#if !defined(BOOST_HASH_HAS_STRING_VIEW)
-#   define BOOST_HASH_HAS_STRING_VIEW 0
-#endif
-
-#if !defined(BOOST_HASH_HAS_OPTIONAL)
-#   define BOOST_HASH_HAS_OPTIONAL 0
-#endif
-
-#if !defined(BOOST_HASH_HAS_VARIANT)
-#   define BOOST_HASH_HAS_VARIANT 0
-#endif
-
-#if BOOST_HASH_HAS_STRING_VIEW
-#   include <string_view>
-#endif
-
-#if BOOST_HASH_HAS_OPTIONAL
-#   include <optional>
-#endif
-
-#if BOOST_HASH_HAS_VARIANT
-#   include <variant>
-#endif
-
 namespace boost
 {
     namespace hash_detail
@@ -217,7 +177,7 @@ namespace boost
     std::size_t hash_value(
         std::basic_string<Ch, std::char_traits<Ch>, A> const&);
 
-#if BOOST_HASH_HAS_STRING_VIEW
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
     template <class Ch>
     std::size_t hash_value(
         std::basic_string_view<Ch, std::char_traits<Ch> > const&);
@@ -226,12 +186,12 @@ namespace boost
     template <typename T>
     typename boost::hash_detail::float_numbers<T>::type hash_value(T);
 
-#if BOOST_HASH_HAS_OPTIONAL
+#if !defined(BOOST_NO_CXX17_HDR_OPTIONAL)
     template <typename T>
     std::size_t hash_value(std::optional<T> const&);
 #endif
 
-#if BOOST_HASH_HAS_VARIANT
+#if !defined(BOOST_NO_CXX17_HDR_VARIANT)
     std::size_t hash_value(std::monostate);
     template <typename... Types>
     std::size_t hash_value(std::variant<Types...> const&);
@@ -471,7 +431,7 @@ namespace boost
         return hash_range(v.begin(), v.end());
     }
 
-#if BOOST_HASH_HAS_STRING_VIEW
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
     template <class Ch>
     inline std::size_t hash_value(
         std::basic_string_view<Ch, std::char_traits<Ch> > const& v)
@@ -486,7 +446,7 @@ namespace boost
         return boost::hash_detail::float_hash_value(v);
     }
 
-#if BOOST_HASH_HAS_OPTIONAL
+#if !defined(BOOST_NO_CXX17_HDR_OPTIONAL)
     template <typename T>
     inline std::size_t hash_value(std::optional<T> const& v) {
         if (!v) {
@@ -499,7 +459,7 @@ namespace boost
     }
 #endif
 
-#if BOOST_HASH_HAS_VARIANT
+#if !defined(BOOST_NO_CXX17_HDR_VARIANT)
     inline std::size_t hash_value(std::monostate) {
         return 0x87654321;
     }
@@ -618,7 +578,7 @@ namespace boost
     BOOST_HASH_SPECIALIZE_REF(std::basic_string<char32_t>)
 #endif
 
-#if BOOST_HASH_HAS_STRING_VIEW
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
     BOOST_HASH_SPECIALIZE_REF(std::string_view)
 #   if !defined(BOOST_NO_STD_WSTRING) && !defined(BOOST_NO_INTRINSIC_WCHAR_T)
     BOOST_HASH_SPECIALIZE_REF(std::wstring_view)
@@ -641,12 +601,12 @@ namespace boost
     BOOST_HASH_SPECIALIZE(boost::uint128_type)
 #endif
 
-#if BOOST_HASH_HAS_OPTIONAL
+#if !defined(BOOST_NO_CXX17_HDR_OPTIONAL)
     template <typename T>
     BOOST_HASH_SPECIALIZE_TEMPLATE_REF(std::optional<T>)
 #endif
 
-#if !defined(BOOST_HASH_HAS_VARIANT)
+#if !defined(BOOST_NO_CXX17_HDR_VARIANT)
     template <typename... T>
     BOOST_HASH_SPECIALIZE_TEMPLATE_REF(std::variant<T...>)
     BOOST_HASH_SPECIALIZE(std::monostate)
diff --git a/test/hash_info.cpp b/test/hash_info.cpp
index b683746..2a6c2c1 100644
--- a/test/hash_info.cpp
+++ b/test/hash_info.cpp
@@ -37,10 +37,9 @@ void write_compiler_info() {
         {1700, "Visual C++ 11.0, VS2012"},
         {1800, "Visual C++ 12.0, VS2013"},
         {1900, "Visual C++ 14.00, VS2015"},
-        {1910, "Visual C++ 14.10, VS2017 15.1/2"},
-        {1911, "Visual C++ 14.11, VS2017 15.3/4"},
-        {1912, "Visual C++ 14.12, VS2017 15.5"},
-        {1913, "Visual C++ 14.13, VS2017 15.6"}
+        {1910, "Visual C++ 14.1x, VS2017"},
+        {1920, "Visual C++ 14.2x, VS2019"},
+        {1930, "Visual C++ 14.3x, VS2022"},
     };
 
     msvc_version msvc = { BOOST_MSVC, "" };
@@ -65,38 +64,42 @@ void write_compiler_info() {
 int main() {
     write_compiler_info();
 
-#if defined(__cplusplus)
     std::cout << "__cplusplus: "
         << __cplusplus
         << std::endl;
+
+    std::cout << "BOOST_CXX_VERSION: "
+        << BOOST_CXX_VERSION
+        << std::endl;
+
+#if defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
+    std::cout << "No <string_view>" << std::endl;
+#else
+    std::cout << "Has <string_view>" << std::endl;
 #endif
 
-    std::cout << "BOOST_HASH_CXX17: "
-        << BOOST_HASH_CXX17
-        << std::endl;
+#if defined(BOOST_NO_CXX17_HDR_OPTIONAL)
+    std::cout << "No <optional>" << std::endl;
+#else
+    std::cout << "Has <optional>" << std::endl;
+#endif
 
-    std::cout << "BOOST_HASH_HAS_STRING_VIEW: "
-        << BOOST_HASH_HAS_STRING_VIEW
-        << std::endl;
-
-    std::cout << "BOOST_HASH_HAS_OPTIONAL: "
-        << BOOST_HASH_HAS_OPTIONAL
-        << std::endl;
-
-    std::cout << "BOOST_HASH_HAS_VARIANT: "
-        << BOOST_HASH_HAS_VARIANT
-        << std::endl;
+#if defined(BOOST_NO_CXX17_HDR_VARIANT)
+    std::cout << "No <variant>" << std::endl;
+#else
+    std::cout << "Has <variant>" << std::endl;
+#endif
 
 #if defined(BOOST_NO_CXX11_HDR_TYPEINDEX)
     std::cout << "No <typeindex>" << std::endl;
 #else
-    std::cout << "<typeindex>" << std::endl;
+    std::cout << "Has <typeindex>" << std::endl;
 #endif
 
 #if defined(BOOST_NO_CXX11_HDR_SYSTEM_ERROR)
     std::cout << "No <system_error>" << std::endl;
 #else
-    std::cout << "<system_error>" << std::endl;
+    std::cout << "Has <system_error>" << std::endl;
 #endif
 
 }
diff --git a/test/hash_optional_test.cpp b/test/hash_optional_test.cpp
index 4469395..5ad2a18 100644
--- a/test/hash_optional_test.cpp
+++ b/test/hash_optional_test.cpp
@@ -11,7 +11,7 @@
 #include <boost/config.hpp>
 #include <boost/core/lightweight_test.hpp>
 
-#if BOOST_HASH_HAS_OPTIONAL
+#if !defined(BOOST_NO_CXX17_HDR_OPTIONAL)
 
 #include <optional>
 #include <string>
@@ -60,7 +60,7 @@ void test_optional_string()
 
 int main()
 {
-#if BOOST_HASH_HAS_OPTIONAL
+#if !defined(BOOST_NO_CXX17_HDR_OPTIONAL)
     test_optional_int();
     test_optional_string();
 #else
diff --git a/test/hash_string_test.cpp b/test/hash_string_test.cpp
index 712c639..10f9847 100644
--- a/test/hash_string_test.cpp
+++ b/test/hash_string_test.cpp
@@ -176,7 +176,7 @@ int main()
 #endif
 
     generic_string_tests((std::string*) 0);
-#if BOOST_HASH_HAS_STRING_VIEW
+#if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
     generic_string_tests((std::string_view*) 0);
 #endif
 
diff --git a/test/hash_variant_test.cpp b/test/hash_variant_test.cpp
index 31520f4..2cf6426 100644
--- a/test/hash_variant_test.cpp
+++ b/test/hash_variant_test.cpp
@@ -11,7 +11,7 @@
 #include <boost/config.hpp>
 #include <boost/core/lightweight_test.hpp>
 
-#if BOOST_HASH_HAS_VARIANT
+#if !defined(BOOST_NO_CXX17_HDR_VARIANT)
 
 #include <variant>
 #include <string>
@@ -90,7 +90,7 @@ void test_variant_unique_types()
 
 int main()
 {
-#if BOOST_HASH_HAS_VARIANT
+#if !defined(BOOST_NO_CXX17_HDR_VARIANT)
     test_variant_int();
     test_variant_unique_types();
 #else