[libc++] implement std::flat_multimap

Author: huixie90

libcxx/docs/Status/Cxx23Papers.csv

@@ -52,7 +52,7 @@
 "`P2443R1 <https://wg21.link/P2443R1>`__","``views::chunk_by``","2022-02 (Virtual)","|Complete|","18.0",""
 "","","","","",""
 "`P0009R18 <https://wg21.link/P0009R18>`__","mdspan: A Non-Owning Multidimensional Array Reference","2022-07 (Virtual)","|Complete|","18.0",""
-"`P0429R9 <https://wg21.link/P0429R9>`__","A Standard ``flat_map``","2022-07 (Virtual)","|In progress|","",""
+"`P0429R9 <https://wg21.link/P0429R9>`__","A Standard ``flat_map``","2022-07 (Virtual)","|Complete|","20.0",""
 "`P1169R4 <https://wg21.link/P1169R4>`__","``static operator()``","2022-07 (Virtual)","|Complete|","16.0",""
 "`P1222R4 <https://wg21.link/P1222R4>`__","A Standard ``flat_set``","2022-07 (Virtual)","","",""
 "`P1223R5 <https://wg21.link/P1223R5>`__","``ranges::find_last()``, ``ranges::find_last_if()``, and ``ranges::find_last_if_not()``","2022-07 (Virtual)","|Complete|","19.0",""

libcxx/include/CMakeLists.txt

@@ -359,7 +359,9 @@ set(files
   __filesystem/space_info.h
   __filesystem/u8path.h
   __flat_map/flat_map.h
+  __flat_map/flat_multimap.h
   __flat_map/sorted_unique.h
+  __flat_map/sorted_equivalent.h
   __format/buffer.h
   __format/concepts.h
   __format/container_adaptor.h

libcxx/include/__flat_map/flat_multimap.h

@@ -0,0 +1,31 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___FLAT_MAP_SORTED_EQUIVALENT_H
+#define _LIBCPP___FLAT_MAP_SORTED_EQUIVALENT_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 23
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct sorted_equivalent_t {
+  explicit sorted_equivalent_t() = default;
+};
+inline constexpr sorted_equivalent_t sorted_equivalent{};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 23
+
+#endif // _LIBCPP___FLAT_MAP_SORTED_EQUIVALENT_H

libcxx/include/__flat_map/sorted_equivalent.h

@@ -35,12 +35,33 @@ namespace std {
            class Predicate>
     typename flat_map<Key, T, Compare, KeyContainer, MappedContainer>::size_type
       erase_if(flat_map<Key, T, Compare, KeyContainer, MappedContainer>& c, Predicate pred);
+
+  // [flat.multimap], class template flat_multimap
+  template<class Key, class T, class Compare = less<Key>,
+           class KeyContainer = vector<Key>, class MappedContainer = vector<T>>
+    class flat_multimap;
+
+  struct sorted_equivalent_t { explicit sorted_equivalent_t() = default; };
+  inline constexpr sorted_equivalent_t sorted_equivalent{};
+
+  template<class Key, class T, class Compare, class KeyContainer, class MappedContainer,
+           class Allocator>
+    struct uses_allocator<flat_multimap<Key, T, Compare, KeyContainer, MappedContainer>,
+                          Allocator>;
+
+  // [flat.multimap.erasure], erasure for flat_multimap
+  template<class Key, class T, class Compare, class KeyContainer, class MappedContainer,
+           class Predicate>
+    typename flat_multimap<Key, T, Compare, KeyContainer, MappedContainer>::size_type
+      erase_if(flat_multimap<Key, T, Compare, KeyContainer, MappedContainer>& c, Predicate pred);
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
 #include <__flat_map/flat_map.h>
+#include <__flat_map/flat_multimap.h>
 #include <__flat_map/sorted_unique.h>
+#include <__flat_map/sorted_equivalent.h>
 #include <version>
 
 // standard required includes

libcxx/include/flat_map

@@ -1232,7 +1232,9 @@ module std [system] {
 
   module flat_map {
     module flat_map                       { header "__flat_map/flat_map.h" }
+    module flat_multimap                  { header "__flat_map/flat_multimap.h" }
     module sorted_unique                  { header "__flat_map/sorted_unique.h" }
+    module sorted_equivalent              { header "__flat_map/sorted_equivalent.h" }
 
     header "flat_map"
     export *

libcxx/include/module.modulemap

@@ -479,6 +479,7 @@ __cpp_lib_void_t                                        201411L <type_traits>
 # define __cpp_lib_format_ranges                        202207L
 // # define __cpp_lib_formatters                           202302L
 # define __cpp_lib_forward_like                         202207L
+# define __cpp_lib_flat_map                             202207L
 # define __cpp_lib_invoke_r                             202106L
 # define __cpp_lib_ios_noreplace                        202207L
 # if __has_builtin(__builtin_is_implicit_lifetime)

libcxx/include/version

@@ -20,14 +20,12 @@ export namespace std {
   // [flat.map.erasure], erasure for flat_map
   using std::erase_if;
 
-#endif // _LIBCPP_STD_VER >= 23
-#if 0
   // [flat.multimap], class template flat_multimap
   using std::flat_multimap;
 
   using std::sorted_equivalent;
   using std::sorted_equivalent_t;
 
   // [flat.multimap.erasure], erasure for flat_multimap
-#endif
+#endif // _LIBCPP_STD_VER >= 23
 } // namespace std

libcxx/modules/std/flat_map.inc

@@ -0,0 +1,50 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// <flat_map>
+
+// struct sorted_equivalent_t { explicit sorted_equivalent_t() = default; };
+// inline constexpr sorted_equivalent_t sorted_equivalent{};
+
+#include <cassert>
+#include <concepts>
+#include <flat_map>
+#include <type_traits>
+
+template <class T>
+void implicit_test(T) {}
+
+template <class T>
+concept HasImplicitDefaultCtor = requires { implicit_test<T>({}); };
+
+static_assert(std::is_default_constructible_v<std::sorted_equivalent_t>);
+static_assert(std::is_trivially_default_constructible_v<std::sorted_equivalent_t>);
+static_assert(!HasImplicitDefaultCtor<std::sorted_equivalent_t>);
+
+constexpr bool test() {
+  {
+    [[maybe_unused]] std::sorted_equivalent_t s;
+  }
+  {
+    [[maybe_unused]] std::same_as<const std::sorted_equivalent_t&> decltype(auto) s = (std::sorted_equivalent);
+  }
+  {
+    [[maybe_unused]] std::same_as<const std::sorted_equivalent_t> decltype(auto) copy = std::sorted_equivalent;
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/containers/container.adaptors/flat.map.syn/sorted_equivalent.pass.cpp

@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// <flat_map>
+
+// class flat_multimap
+
+// [[nodiscard]] bool empty() const noexcept;
+
+#include <flat_map>
+#include <cassert>
+#include <deque>
+#include <functional>
+#include <utility>
+#include <vector>
+
+#include "MinSequenceContainer.h"
+#include "test_macros.h"
+#include "min_allocator.h"
+
+template <class KeyContainer, class ValueContainer>
+void test() {
+  using M = std::flat_multimap<int, double, std::less<int>, KeyContainer, ValueContainer>;
+  M m;
+  ASSERT_SAME_TYPE(decltype(m.empty()), bool);
+  ASSERT_NOEXCEPT(m.empty());
+  assert(m.empty());
+  assert(std::as_const(m).empty());
+  m = {{1, 1.0}, {1, 2.0}};
+  assert(!m.empty());
+  m.clear();
+  assert(m.empty());
+}
+
+int main(int, char**) {
+  test<std::vector<int>, std::vector<double>>();
+  test<std::deque<int>, std::vector<double>>();
+  test<MinSequenceContainer<int>, MinSequenceContainer<double>>();
+  test<std::vector<int, min_allocator<int>>, std::vector<double, min_allocator<double>>>();
+
+  return 0;
+}