about summary refs log tree commit diff
path: root/third_party/abseil_cpp/absl/container/node_hash_map.h
diff options
context:
space:
mode:
Diffstat (limited to 'third_party/abseil_cpp/absl/container/node_hash_map.h')
-rw-r--r--third_party/abseil_cpp/absl/container/node_hash_map.h591
1 files changed, 591 insertions, 0 deletions
diff --git a/third_party/abseil_cpp/absl/container/node_hash_map.h b/third_party/abseil_cpp/absl/container/node_hash_map.h
new file mode 100644
index 000000000000..174b971e99ce
--- /dev/null
+++ b/third_party/abseil_cpp/absl/container/node_hash_map.h
@@ -0,0 +1,591 @@
+// Copyright 2018 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// -----------------------------------------------------------------------------
+// File: node_hash_map.h
+// -----------------------------------------------------------------------------
+//
+// An `absl::node_hash_map<K, V>` is an unordered associative container of
+// unique keys and associated values designed to be a more efficient replacement
+// for `std::unordered_map`. Like `unordered_map`, search, insertion, and
+// deletion of map elements can be done as an `O(1)` operation. However,
+// `node_hash_map` (and other unordered associative containers known as the
+// collection of Abseil "Swiss tables") contain other optimizations that result
+// in both memory and computation advantages.
+//
+// In most cases, your default choice for a hash map should be a map of type
+// `flat_hash_map`. However, if you need pointer stability and cannot store
+// a `flat_hash_map` with `unique_ptr` elements, a `node_hash_map` may be a
+// valid alternative. As well, if you are migrating your code from using
+// `std::unordered_map`, a `node_hash_map` provides a more straightforward
+// migration, because it guarantees pointer stability. Consider migrating to
+// `node_hash_map` and perhaps converting to a more efficient `flat_hash_map`
+// upon further review.
+
+#ifndef ABSL_CONTAINER_NODE_HASH_MAP_H_
+#define ABSL_CONTAINER_NODE_HASH_MAP_H_
+
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+#include "absl/algorithm/container.h"
+#include "absl/container/internal/container_memory.h"
+#include "absl/container/internal/hash_function_defaults.h"  // IWYU pragma: export
+#include "absl/container/internal/node_hash_policy.h"
+#include "absl/container/internal/raw_hash_map.h"  // IWYU pragma: export
+#include "absl/memory/memory.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace container_internal {
+template <class Key, class Value>
+class NodeHashMapPolicy;
+}  // namespace container_internal
+
+// -----------------------------------------------------------------------------
+// absl::node_hash_map
+// -----------------------------------------------------------------------------
+//
+// An `absl::node_hash_map<K, V>` is an unordered associative container which
+// has been optimized for both speed and memory footprint in most common use
+// cases. Its interface is similar to that of `std::unordered_map<K, V>` with
+// the following notable differences:
+//
+// * Supports heterogeneous lookup, through `find()`, `operator[]()` and
+//   `insert()`, provided that the map is provided a compatible heterogeneous
+//   hashing function and equality operator.
+// * Contains a `capacity()` member function indicating the number of element
+//   slots (open, deleted, and empty) within the hash map.
+// * Returns `void` from the `erase(iterator)` overload.
+//
+// By default, `node_hash_map` uses the `absl::Hash` hashing framework.
+// All fundamental and Abseil types that support the `absl::Hash` framework have
+// a compatible equality operator for comparing insertions into `node_hash_map`.
+// If your type is not yet supported by the `absl::Hash` framework, see
+// absl/hash/hash.h for information on extending Abseil hashing to user-defined
+// types.
+//
+// Example:
+//
+//   // Create a node hash map of three strings (that map to strings)
+//   absl::node_hash_map<std::string, std::string> ducks =
+//     {{"a", "huey"}, {"b", "dewey"}, {"c", "louie"}};
+//
+//  // Insert a new element into the node hash map
+//  ducks.insert({"d", "donald"}};
+//
+//  // Force a rehash of the node hash map
+//  ducks.rehash(0);
+//
+//  // Find the element with the key "b"
+//  std::string search_key = "b";
+//  auto result = ducks.find(search_key);
+//  if (result != ducks.end()) {
+//    std::cout << "Result: " << result->second << std::endl;
+//  }
+template <class Key, class Value,
+          class Hash = absl::container_internal::hash_default_hash<Key>,
+          class Eq = absl::container_internal::hash_default_eq<Key>,
+          class Alloc = std::allocator<std::pair<const Key, Value>>>
+class node_hash_map
+    : public absl::container_internal::raw_hash_map<
+          absl::container_internal::NodeHashMapPolicy<Key, Value>, Hash, Eq,
+          Alloc> {
+  using Base = typename node_hash_map::raw_hash_map;
+
+ public:
+  // Constructors and Assignment Operators
+  //
+  // A node_hash_map supports the same overload set as `std::unordered_map`
+  // for construction and assignment:
+  //
+  // *  Default constructor
+  //
+  //    // No allocation for the table's elements is made.
+  //    absl::node_hash_map<int, std::string> map1;
+  //
+  // * Initializer List constructor
+  //
+  //   absl::node_hash_map<int, std::string> map2 =
+  //       {{1, "huey"}, {2, "dewey"}, {3, "louie"},};
+  //
+  // * Copy constructor
+  //
+  //   absl::node_hash_map<int, std::string> map3(map2);
+  //
+  // * Copy assignment operator
+  //
+  //  // Hash functor and Comparator are copied as well
+  //  absl::node_hash_map<int, std::string> map4;
+  //  map4 = map3;
+  //
+  // * Move constructor
+  //
+  //   // Move is guaranteed efficient
+  //   absl::node_hash_map<int, std::string> map5(std::move(map4));
+  //
+  // * Move assignment operator
+  //
+  //   // May be efficient if allocators are compatible
+  //   absl::node_hash_map<int, std::string> map6;
+  //   map6 = std::move(map5);
+  //
+  // * Range constructor
+  //
+  //   std::vector<std::pair<int, std::string>> v = {{1, "a"}, {2, "b"}};
+  //   absl::node_hash_map<int, std::string> map7(v.begin(), v.end());
+  node_hash_map() {}
+  using Base::Base;
+
+  // node_hash_map::begin()
+  //
+  // Returns an iterator to the beginning of the `node_hash_map`.
+  using Base::begin;
+
+  // node_hash_map::cbegin()
+  //
+  // Returns a const iterator to the beginning of the `node_hash_map`.
+  using Base::cbegin;
+
+  // node_hash_map::cend()
+  //
+  // Returns a const iterator to the end of the `node_hash_map`.
+  using Base::cend;
+
+  // node_hash_map::end()
+  //
+  // Returns an iterator to the end of the `node_hash_map`.
+  using Base::end;
+
+  // node_hash_map::capacity()
+  //
+  // Returns the number of element slots (assigned, deleted, and empty)
+  // available within the `node_hash_map`.
+  //
+  // NOTE: this member function is particular to `absl::node_hash_map` and is
+  // not provided in the `std::unordered_map` API.
+  using Base::capacity;
+
+  // node_hash_map::empty()
+  //
+  // Returns whether or not the `node_hash_map` is empty.
+  using Base::empty;
+
+  // node_hash_map::max_size()
+  //
+  // Returns the largest theoretical possible number of elements within a
+  // `node_hash_map` under current memory constraints. This value can be thought
+  // of as the largest value of `std::distance(begin(), end())` for a
+  // `node_hash_map<K, V>`.
+  using Base::max_size;
+
+  // node_hash_map::size()
+  //
+  // Returns the number of elements currently within the `node_hash_map`.
+  using Base::size;
+
+  // node_hash_map::clear()
+  //
+  // Removes all elements from the `node_hash_map`. Invalidates any references,
+  // pointers, or iterators referring to contained elements.
+  //
+  // NOTE: this operation may shrink the underlying buffer. To avoid shrinking
+  // the underlying buffer call `erase(begin(), end())`.
+  using Base::clear;
+
+  // node_hash_map::erase()
+  //
+  // Erases elements within the `node_hash_map`. Erasing does not trigger a
+  // rehash. Overloads are listed below.
+  //
+  // void erase(const_iterator pos):
+  //
+  //   Erases the element at `position` of the `node_hash_map`, returning
+  //   `void`.
+  //
+  //   NOTE: this return behavior is different than that of STL containers in
+  //   general and `std::unordered_map` in particular.
+  //
+  // iterator erase(const_iterator first, const_iterator last):
+  //
+  //   Erases the elements in the open interval [`first`, `last`), returning an
+  //   iterator pointing to `last`.
+  //
+  // size_type erase(const key_type& key):
+  //
+  //   Erases the element with the matching key, if it exists.
+  using Base::erase;
+
+  // node_hash_map::insert()
+  //
+  // Inserts an element of the specified value into the `node_hash_map`,
+  // returning an iterator pointing to the newly inserted element, provided that
+  // an element with the given key does not already exist. If rehashing occurs
+  // due to the insertion, all iterators are invalidated. Overloads are listed
+  // below.
+  //
+  // std::pair<iterator,bool> insert(const init_type& value):
+  //
+  //   Inserts a value into the `node_hash_map`. Returns a pair consisting of an
+  //   iterator to the inserted element (or to the element that prevented the
+  //   insertion) and a `bool` denoting whether the insertion took place.
+  //
+  // std::pair<iterator,bool> insert(T&& value):
+  // std::pair<iterator,bool> insert(init_type&& value):
+  //
+  //   Inserts a moveable value into the `node_hash_map`. Returns a `std::pair`
+  //   consisting of an iterator to the inserted element (or to the element that
+  //   prevented the insertion) and a `bool` denoting whether the insertion took
+  //   place.
+  //
+  // iterator insert(const_iterator hint, const init_type& value):
+  // iterator insert(const_iterator hint, T&& value):
+  // iterator insert(const_iterator hint, init_type&& value);
+  //
+  //   Inserts a value, using the position of `hint` as a non-binding suggestion
+  //   for where to begin the insertion search. Returns an iterator to the
+  //   inserted element, or to the existing element that prevented the
+  //   insertion.
+  //
+  // void insert(InputIterator first, InputIterator last):
+  //
+  //   Inserts a range of values [`first`, `last`).
+  //
+  //   NOTE: Although the STL does not specify which element may be inserted if
+  //   multiple keys compare equivalently, for `node_hash_map` we guarantee the
+  //   first match is inserted.
+  //
+  // void insert(std::initializer_list<init_type> ilist):
+  //
+  //   Inserts the elements within the initializer list `ilist`.
+  //
+  //   NOTE: Although the STL does not specify which element may be inserted if
+  //   multiple keys compare equivalently within the initializer list, for
+  //   `node_hash_map` we guarantee the first match is inserted.
+  using Base::insert;
+
+  // node_hash_map::insert_or_assign()
+  //
+  // Inserts an element of the specified value into the `node_hash_map` provided
+  // that a value with the given key does not already exist, or replaces it with
+  // the element value if a key for that value already exists, returning an
+  // iterator pointing to the newly inserted element. If rehashing occurs due to
+  // the insertion, all iterators are invalidated. Overloads are listed
+  // below.
+  //
+  // std::pair<iterator, bool> insert_or_assign(const init_type& k, T&& obj):
+  // std::pair<iterator, bool> insert_or_assign(init_type&& k, T&& obj):
+  //
+  //   Inserts/Assigns (or moves) the element of the specified key into the
+  //   `node_hash_map`.
+  //
+  // iterator insert_or_assign(const_iterator hint,
+  //                           const init_type& k, T&& obj):
+  // iterator insert_or_assign(const_iterator hint, init_type&& k, T&& obj):
+  //
+  //   Inserts/Assigns (or moves) the element of the specified key into the
+  //   `node_hash_map` using the position of `hint` as a non-binding suggestion
+  //   for where to begin the insertion search.
+  using Base::insert_or_assign;
+
+  // node_hash_map::emplace()
+  //
+  // Inserts an element of the specified value by constructing it in-place
+  // within the `node_hash_map`, provided that no element with the given key
+  // already exists.
+  //
+  // The element may be constructed even if there already is an element with the
+  // key in the container, in which case the newly constructed element will be
+  // destroyed immediately. Prefer `try_emplace()` unless your key is not
+  // copyable or moveable.
+  //
+  // If rehashing occurs due to the insertion, all iterators are invalidated.
+  using Base::emplace;
+
+  // node_hash_map::emplace_hint()
+  //
+  // Inserts an element of the specified value by constructing it in-place
+  // within the `node_hash_map`, using the position of `hint` as a non-binding
+  // suggestion for where to begin the insertion search, and only inserts
+  // provided that no element with the given key already exists.
+  //
+  // The element may be constructed even if there already is an element with the
+  // key in the container, in which case the newly constructed element will be
+  // destroyed immediately. Prefer `try_emplace()` unless your key is not
+  // copyable or moveable.
+  //
+  // If rehashing occurs due to the insertion, all iterators are invalidated.
+  using Base::emplace_hint;
+
+  // node_hash_map::try_emplace()
+  //
+  // Inserts an element of the specified value by constructing it in-place
+  // within the `node_hash_map`, provided that no element with the given key
+  // already exists. Unlike `emplace()`, if an element with the given key
+  // already exists, we guarantee that no element is constructed.
+  //
+  // If rehashing occurs due to the insertion, all iterators are invalidated.
+  // Overloads are listed below.
+  //
+  //   std::pair<iterator, bool> try_emplace(const key_type& k, Args&&... args):
+  //   std::pair<iterator, bool> try_emplace(key_type&& k, Args&&... args):
+  //
+  // Inserts (via copy or move) the element of the specified key into the
+  // `node_hash_map`.
+  //
+  //   iterator try_emplace(const_iterator hint,
+  //                        const init_type& k, Args&&... args):
+  //   iterator try_emplace(const_iterator hint, init_type&& k, Args&&... args):
+  //
+  // Inserts (via copy or move) the element of the specified key into the
+  // `node_hash_map` using the position of `hint` as a non-binding suggestion
+  // for where to begin the insertion search.
+  //
+  // All `try_emplace()` overloads make the same guarantees regarding rvalue
+  // arguments as `std::unordered_map::try_emplace()`, namely that these
+  // functions will not move from rvalue arguments if insertions do not happen.
+  using Base::try_emplace;
+
+  // node_hash_map::extract()
+  //
+  // Extracts the indicated element, erasing it in the process, and returns it
+  // as a C++17-compatible node handle. Overloads are listed below.
+  //
+  // node_type extract(const_iterator position):
+  //
+  //   Extracts the key,value pair of the element at the indicated position and
+  //   returns a node handle owning that extracted data.
+  //
+  // node_type extract(const key_type& x):
+  //
+  //   Extracts the key,value pair of the element with a key matching the passed
+  //   key value and returns a node handle owning that extracted data. If the
+  //   `node_hash_map` does not contain an element with a matching key, this
+  //   function returns an empty node handle.
+  using Base::extract;
+
+  // node_hash_map::merge()
+  //
+  // Extracts elements from a given `source` node hash map into this
+  // `node_hash_map`. If the destination `node_hash_map` already contains an
+  // element with an equivalent key, that element is not extracted.
+  using Base::merge;
+
+  // node_hash_map::swap(node_hash_map& other)
+  //
+  // Exchanges the contents of this `node_hash_map` with those of the `other`
+  // node hash map, avoiding invocation of any move, copy, or swap operations on
+  // individual elements.
+  //
+  // All iterators and references on the `node_hash_map` remain valid, excepting
+  // for the past-the-end iterator, which is invalidated.
+  //
+  // `swap()` requires that the node hash map's hashing and key equivalence
+  // functions be Swappable, and are exchaged using unqualified calls to
+  // non-member `swap()`. If the map's allocator has
+  // `std::allocator_traits<allocator_type>::propagate_on_container_swap::value`
+  // set to `true`, the allocators are also exchanged using an unqualified call
+  // to non-member `swap()`; otherwise, the allocators are not swapped.
+  using Base::swap;
+
+  // node_hash_map::rehash(count)
+  //
+  // Rehashes the `node_hash_map`, setting the number of slots to be at least
+  // the passed value. If the new number of slots increases the load factor more
+  // than the current maximum load factor
+  // (`count` < `size()` / `max_load_factor()`), then the new number of slots
+  // will be at least `size()` / `max_load_factor()`.
+  //
+  // To force a rehash, pass rehash(0).
+  using Base::rehash;
+
+  // node_hash_map::reserve(count)
+  //
+  // Sets the number of slots in the `node_hash_map` to the number needed to
+  // accommodate at least `count` total elements without exceeding the current
+  // maximum load factor, and may rehash the container if needed.
+  using Base::reserve;
+
+  // node_hash_map::at()
+  //
+  // Returns a reference to the mapped value of the element with key equivalent
+  // to the passed key.
+  using Base::at;
+
+  // node_hash_map::contains()
+  //
+  // Determines whether an element with a key comparing equal to the given `key`
+  // exists within the `node_hash_map`, returning `true` if so or `false`
+  // otherwise.
+  using Base::contains;
+
+  // node_hash_map::count(const Key& key) const
+  //
+  // Returns the number of elements with a key comparing equal to the given
+  // `key` within the `node_hash_map`. note that this function will return
+  // either `1` or `0` since duplicate keys are not allowed within a
+  // `node_hash_map`.
+  using Base::count;
+
+  // node_hash_map::equal_range()
+  //
+  // Returns a closed range [first, last], defined by a `std::pair` of two
+  // iterators, containing all elements with the passed key in the
+  // `node_hash_map`.
+  using Base::equal_range;
+
+  // node_hash_map::find()
+  //
+  // Finds an element with the passed `key` within the `node_hash_map`.
+  using Base::find;
+
+  // node_hash_map::operator[]()
+  //
+  // Returns a reference to the value mapped to the passed key within the
+  // `node_hash_map`, performing an `insert()` if the key does not already
+  // exist. If an insertion occurs and results in a rehashing of the container,
+  // all iterators are invalidated. Otherwise iterators are not affected and
+  // references are not invalidated. Overloads are listed below.
+  //
+  // T& operator[](const Key& key):
+  //
+  //   Inserts an init_type object constructed in-place if the element with the
+  //   given key does not exist.
+  //
+  // T& operator[](Key&& key):
+  //
+  //   Inserts an init_type object constructed in-place provided that an element
+  //   with the given key does not exist.
+  using Base::operator[];
+
+  // node_hash_map::bucket_count()
+  //
+  // Returns the number of "buckets" within the `node_hash_map`.
+  using Base::bucket_count;
+
+  // node_hash_map::load_factor()
+  //
+  // Returns the current load factor of the `node_hash_map` (the average number
+  // of slots occupied with a value within the hash map).
+  using Base::load_factor;
+
+  // node_hash_map::max_load_factor()
+  //
+  // Manages the maximum load factor of the `node_hash_map`. Overloads are
+  // listed below.
+  //
+  // float node_hash_map::max_load_factor()
+  //
+  //   Returns the current maximum load factor of the `node_hash_map`.
+  //
+  // void node_hash_map::max_load_factor(float ml)
+  //
+  //   Sets the maximum load factor of the `node_hash_map` to the passed value.
+  //
+  //   NOTE: This overload is provided only for API compatibility with the STL;
+  //   `node_hash_map` will ignore any set load factor and manage its rehashing
+  //   internally as an implementation detail.
+  using Base::max_load_factor;
+
+  // node_hash_map::get_allocator()
+  //
+  // Returns the allocator function associated with this `node_hash_map`.
+  using Base::get_allocator;
+
+  // node_hash_map::hash_function()
+  //
+  // Returns the hashing function used to hash the keys within this
+  // `node_hash_map`.
+  using Base::hash_function;
+
+  // node_hash_map::key_eq()
+  //
+  // Returns the function used for comparing keys equality.
+  using Base::key_eq;
+};
+
+// erase_if(node_hash_map<>, Pred)
+//
+// Erases all elements that satisfy the predicate `pred` from the container `c`.
+template <typename K, typename V, typename H, typename E, typename A,
+          typename Predicate>
+void erase_if(node_hash_map<K, V, H, E, A>& c, Predicate pred) {
+  container_internal::EraseIf(pred, &c);
+}
+
+namespace container_internal {
+
+template <class Key, class Value>
+class NodeHashMapPolicy
+    : public absl::container_internal::node_hash_policy<
+          std::pair<const Key, Value>&, NodeHashMapPolicy<Key, Value>> {
+  using value_type = std::pair<const Key, Value>;
+
+ public:
+  using key_type = Key;
+  using mapped_type = Value;
+  using init_type = std::pair</*non const*/ key_type, mapped_type>;
+
+  template <class Allocator, class... Args>
+  static value_type* new_element(Allocator* alloc, Args&&... args) {
+    using PairAlloc = typename absl::allocator_traits<
+        Allocator>::template rebind_alloc<value_type>;
+    PairAlloc pair_alloc(*alloc);
+    value_type* res =
+        absl::allocator_traits<PairAlloc>::allocate(pair_alloc, 1);
+    absl::allocator_traits<PairAlloc>::construct(pair_alloc, res,
+                                                 std::forward<Args>(args)...);
+    return res;
+  }
+
+  template <class Allocator>
+  static void delete_element(Allocator* alloc, value_type* pair) {
+    using PairAlloc = typename absl::allocator_traits<
+        Allocator>::template rebind_alloc<value_type>;
+    PairAlloc pair_alloc(*alloc);
+    absl::allocator_traits<PairAlloc>::destroy(pair_alloc, pair);
+    absl::allocator_traits<PairAlloc>::deallocate(pair_alloc, pair, 1);
+  }
+
+  template <class F, class... Args>
+  static decltype(absl::container_internal::DecomposePair(
+      std::declval<F>(), std::declval<Args>()...))
+  apply(F&& f, Args&&... args) {
+    return absl::container_internal::DecomposePair(std::forward<F>(f),
+                                                   std::forward<Args>(args)...);
+  }
+
+  static size_t element_space_used(const value_type*) {
+    return sizeof(value_type);
+  }
+
+  static Value& value(value_type* elem) { return elem->second; }
+  static const Value& value(const value_type* elem) { return elem->second; }
+};
+}  // namespace container_internal
+
+namespace container_algorithm_internal {
+
+// Specialization of trait in absl/algorithm/container.h
+template <class Key, class T, class Hash, class KeyEqual, class Allocator>
+struct IsUnorderedContainer<
+    absl::node_hash_map<Key, T, Hash, KeyEqual, Allocator>> : std::true_type {};
+
+}  // namespace container_algorithm_internal
+
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_CONTAINER_NODE_HASH_MAP_H_