Merge pull request #79 from cmazakas/map-contains

Implement `unordered_map::contains()`

include/boost/unordered/unordered_map.hpp

@@ -796,6 +796,23 @@ namespace boost {
       const_iterator find(CompatibleKey const&, CompatibleHash const&,
         CompatiblePredicate const&) const;
 
+      bool contains(const key_type& k) const
+      {
+        return table_.find_node_impl(
+          table::policy::apply_hash(this->hash_function(), k), k,
+          this->key_eq());
+      }
+
+      template <class Key>
+      typename boost::enable_if_c<detail::are_transparent<Key, H, P>::value,
+        bool>::type
+      contains(const Key& k) const
+      {
+        return table_.find_node_impl(
+          table::policy::apply_hash(this->hash_function(), k), k,
+          this->key_eq());
+      }
+
       size_type count(const key_type&) const;
 
       template <class Key>

test/Jamfile.v2

@@ -64,6 +64,7 @@ test-suite unordered
         [ run unordered/scoped_allocator.cpp /boost/filesystem//boost_filesystem ]
         [ run unordered/transparent_tests.cpp ]
         [ run unordered/reserve_tests.cpp ]
+        [ run unordered/contains_tests.cpp ]
 
         [ run unordered/compile_set.cpp : :
             : <define>BOOST_UNORDERED_USE_MOVE

test/unordered/contains_tests.cpp

@@ -0,0 +1,155 @@
+// Copyright 2021 Christian Mazakas.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// clang-format off
+#include "../helpers/prefix.hpp"
+#include <boost/unordered_set.hpp>
+#include <boost/unordered_map.hpp>
+#include "../helpers/postfix.hpp"
+// clang-format on
+
+#include "../helpers/test.hpp"
+
+struct key
+{
+  int x_;
+  static int count_;
+
+  key(int x) : x_(x) { ++count_; }
+  key(key const& k) : x_(k.x_) { ++count_; }
+};
+
+int key::count_;
+
+std::ostream& operator<<(std::ostream& os, key const& k)
+{
+  os << "key { x_: " << k.x_ << " }";
+  return os;
+}
+
+bool operator==(key const& k, int const x) { return k.x_ == x; }
+bool operator==(int const x, key const& k) { return k.x_ == x; }
+
+struct transparent_hasher
+{
+  typedef void is_transparent;
+
+  std::size_t operator()(key const& k) const
+  {
+    return boost::hash<int>()(k.x_);
+  }
+
+  std::size_t operator()(int const k) const { return boost::hash<int>()(k); }
+};
+
+struct transparent_key_equal
+{
+  typedef void is_transparent;
+
+  bool operator()(key const& k1, key const& k2) const { return k1.x_ == k2.x_; }
+  bool operator()(int const x, key const& k1) const { return k1 == x; }
+  bool operator()(key const& k1, int const x) const { return k1 == x; }
+};
+
+struct hasher
+{
+  std::size_t operator()(key const& k) const
+  {
+    return boost::hash<int>()(k.x_);
+  }
+};
+
+struct key_equal
+{
+  bool operator()(key const& k1, key const& k2) const { return k1.x_ == k2.x_; }
+};
+
+void count_reset() { key::count_ = 0; }
+
+template <class UnorderedMap> void test_map_transparent_contains()
+{
+  count_reset();
+
+  UnorderedMap map;
+  bool contains = map.contains(0);
+  BOOST_TEST(!contains);
+
+  BOOST_TEST_EQ(key::count_, 0);
+
+  map.insert(std::make_pair(0, 1337));
+  map.insert(std::make_pair(0, 1338));
+  map.insert(std::make_pair(0, 1339));
+  map.insert(std::make_pair(1, 1340));
+
+  int const expected_key_count = key::count_;
+
+  contains = map.contains(0);
+  BOOST_TEST(contains);
+
+  contains = map.contains(1);
+  BOOST_TEST(contains);
+
+  contains = map.contains(2);
+  BOOST_TEST(!contains);
+
+  BOOST_TEST_EQ(key::count_, expected_key_count);
+}
+
+template <class UnorderedMap> void test_map_non_transparent_contains()
+{
+  count_reset();
+
+  UnorderedMap map;
+  bool contains = map.contains(0);
+  BOOST_TEST(!contains);
+  BOOST_TEST_EQ(key::count_, 1);
+
+  map.insert(std::make_pair(0, 1337));
+  map.insert(std::make_pair(0, 1338));
+  map.insert(std::make_pair(0, 1339));
+  map.insert(std::make_pair(1, 1340));
+
+  int key_count = key::count_;
+
+  contains = map.contains(0);
+  ++key_count;
+  BOOST_TEST(contains);
+
+  contains = map.contains(1);
+  ++key_count;
+  BOOST_TEST(contains);
+
+  contains = map.contains(2);
+  ++key_count;
+  BOOST_TEST(!contains);
+
+  BOOST_TEST_EQ(key::count_, key_count);
+}
+
+void test_map()
+{
+  typedef boost::unordered_map<key, int, transparent_hasher,
+    transparent_key_equal>
+    transparent_map;
+
+  typedef boost::unordered_map<key, int, transparent_hasher, key_equal>
+    non_transparent_map1;
+
+  typedef boost::unordered_map<key, int, hasher, transparent_key_equal>
+    non_transparent_map2;
+
+  typedef boost::unordered_map<key, int, hasher, key_equal>
+    non_transparent_map3;
+
+  test_map_transparent_contains<transparent_map>();
+  test_map_non_transparent_contains<non_transparent_map1>();
+  test_map_non_transparent_contains<non_transparent_map2>();
+  test_map_non_transparent_contains<non_transparent_map3>();
+}
+
+UNORDERED_AUTO_TEST (contains) {
+  test_map();
+}
+
+RUN_TESTS()