Move to C++17 dropping C++11 support

README.md

@@ -92,7 +92,7 @@ If the project has been installed through `make install`, you can also use `find
 
 The library is available in [vcpkg](https://github.com/Microsoft/vcpkg/tree/master/ports/robin-map) and [conan](https://conan.io/center/tsl-robin-map). It's also present in [Debian](https://packages.debian.org/buster/robin-map-dev), [Ubuntu](https://packages.ubuntu.com/disco/robin-map-dev) and [Fedora](https://apps.fedoraproject.org/packages/robin-map-devel) package repositories.
 
-The code should work with any C++11 standard-compliant compiler and has been tested with GCC 4.8.4, Clang 3.5.0 and Visual Studio 2015.
+The code should work with any C++17 standard-compliant compiler.
 
 To run the tests you will need the Boost Test library and CMake.
 

doxygen.conf

@@ -1081,7 +1081,7 @@ CLANG_ASSISTED_PARSING = YES
 # specified with INPUT and INCLUDE_PATH.
 # This tag requires that the tag CLANG_ASSISTED_PARSING is set to YES.
 
-CLANG_OPTIONS          = -std=c++11
+CLANG_OPTIONS          = -std=c++17
 
 #---------------------------------------------------------------------------
 # Configuration options related to the alphabetical class index

include/tsl/robin_hash.h

@@ -66,12 +66,6 @@ template <std::size_t GrowthFactor>
 struct is_power_of_two_policy<tsl::rh::power_of_two_growth_policy<GrowthFactor>>
     : std::true_type {};
 
-// Only available in C++17, we need to be compatible with C++11
-template <class T>
-const T& clamp(const T& v, const T& lo, const T& hi) {
-  return std::min(hi, std::max(lo, v));
-}
-
 template <typename T, typename U>
 static T numeric_cast(U value,
                       const char* error_message = "numeric_cast() failed.") {
@@ -254,22 +248,14 @@ class bucket_entry : public bucket_entry_hash<StoreHash> {
 
   value_type& value() noexcept {
     tsl_rh_assert(!empty());
-#if defined(__cplusplus) && __cplusplus >= 201703L
     return *std::launder(
         reinterpret_cast<value_type*>(std::addressof(m_value)));
-#else
-    return *reinterpret_cast<value_type*>(std::addressof(m_value));
-#endif
   }
 
   const value_type& value() const noexcept {
     tsl_rh_assert(!empty());
-#if defined(__cplusplus) && __cplusplus >= 201703L
     return *std::launder(
         reinterpret_cast<const value_type*>(std::addressof(m_value)));
-#else
-    return *reinterpret_cast<const value_type*>(std::addressof(m_value));
-#endif
   }
 
   distance_type dist_from_ideal_bucket() const noexcept {
@@ -541,7 +527,6 @@ class robin_hash : private Hash, private KeyEqual, private GrowthPolicy {
   };
 
  public:
-#if defined(__cplusplus) && __cplusplus >= 201402L
   robin_hash(size_type bucket_count, const Hash& hash, const KeyEqual& equal,
              const Allocator& alloc,
              float min_load_factor = DEFAULT_MIN_LOAD_FACTOR,
@@ -569,47 +554,6 @@ class robin_hash : private Hash, private KeyEqual, private GrowthPolicy {
     this->min_load_factor(min_load_factor);
     this->max_load_factor(max_load_factor);
   }
-#else
-  /**
-   * C++11 doesn't support the creation of a std::vector with a custom allocator
-   * and 'count' default-inserted elements. The needed contructor `explicit
-   * vector(size_type count, const Allocator& alloc = Allocator());` is only
-   * available in C++14 and later. We thus must resize after using the
-   * `vector(const Allocator& alloc)` constructor.
-   *
-   * We can't use `vector(size_type count, const T& value, const Allocator&
-   * alloc)` as it requires the value T to be copyable.
-   */
-  robin_hash(size_type bucket_count, const Hash& hash, const KeyEqual& equal,
-             const Allocator& alloc,
-             float min_load_factor = DEFAULT_MIN_LOAD_FACTOR,
-             float max_load_factor = DEFAULT_MAX_LOAD_FACTOR)
-      : Hash(hash),
-        KeyEqual(equal),
-        GrowthPolicy(bucket_count),
-        m_buckets_data(alloc),
-        m_buckets(static_empty_bucket_ptr()),
-        m_bucket_count(bucket_count),
-        m_nb_elements(0),
-        m_grow_on_next_insert(false),
-        m_try_shrink_on_next_insert(false) {
-    if (bucket_count > max_bucket_count()) {
-      TSL_RH_THROW_OR_TERMINATE(std::length_error,
-                                "The map exceeds its maximum bucket count.");
-    }
-
-    if (m_bucket_count > 0) {
-      m_buckets_data.resize(m_bucket_count);
-      m_buckets = m_buckets_data.data();
-
-      tsl_rh_assert(!m_buckets_data.empty());
-      m_buckets_data.back().set_as_last_bucket();
-    }
-
-    this->min_load_factor(min_load_factor);
-    this->max_load_factor(max_load_factor);
-  }
-#endif
 
   robin_hash(const robin_hash& other)
       : Hash(other),
@@ -1073,13 +1017,13 @@ class robin_hash : private Hash, private KeyEqual, private GrowthPolicy {
   float max_load_factor() const { return m_max_load_factor; }
 
   void min_load_factor(float ml) {
-    m_min_load_factor = clamp(ml, float(MINIMUM_MIN_LOAD_FACTOR),
-                              float(MAXIMUM_MIN_LOAD_FACTOR));
+    m_min_load_factor = std::clamp(ml, float(MINIMUM_MIN_LOAD_FACTOR),
+                                   float(MAXIMUM_MIN_LOAD_FACTOR));
   }
 
   void max_load_factor(float ml) {
-    m_max_load_factor = clamp(ml, float(MINIMUM_MAX_LOAD_FACTOR),
-                              float(MAXIMUM_MAX_LOAD_FACTOR));
+    m_max_load_factor = std::clamp(ml, float(MINIMUM_MAX_LOAD_FACTOR),
+                                   float(MAXIMUM_MAX_LOAD_FACTOR));
     m_load_threshold = size_type(float(bucket_count()) * m_max_load_factor);
     tsl_rh_assert(bucket_count() == 0 || m_load_threshold < bucket_count());
   }

tests/CMakeLists.txt

@@ -8,7 +8,7 @@ add_executable(tsl_robin_map_tests "main.cpp"
                                    "robin_map_tests.cpp" 
                                    "robin_set_tests.cpp")
 
-target_compile_features(tsl_robin_map_tests PRIVATE cxx_std_11)
+target_compile_features(tsl_robin_map_tests PRIVATE cxx_std_17)
 
 if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU")
     target_compile_options(tsl_robin_map_tests PRIVATE -Werror -Wall -Wextra -Wold-style-cast -DTSL_DEBUG -UNDEBUG)
@@ -18,7 +18,7 @@ endif()
 
 # Boost::unit_test_framework
 set(Boost_USE_STATIC_LIBS ON)
-find_package(Boost 1.54.0 REQUIRED COMPONENTS unit_test_framework)
+find_package(Boost REQUIRED COMPONENTS unit_test_framework)
 target_link_libraries(tsl_robin_map_tests PRIVATE Boost::unit_test_framework)   
 
 # tsl::robin_map