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-rw-r--r--abseil-cpp/absl/container/node_hash_set.h53
1 files changed, 32 insertions, 21 deletions
diff --git a/abseil-cpp/absl/container/node_hash_set.h b/abseil-cpp/absl/container/node_hash_set.h
index 56ce3b6..421ff46 100644
--- a/abseil-cpp/absl/container/node_hash_set.h
+++ b/abseil-cpp/absl/container/node_hash_set.h
@@ -18,7 +18,7 @@
//
// An `absl::node_hash_set<T>` is an unordered associative container designed to
// be a more efficient replacement for `std::unordered_set`. Like
-// `unordered_set`, search, insertion, and deletion of map elements can be done
+// `unordered_set`, search, insertion, and deletion of set elements can be done
// as an `O(1)` operation. However, `node_hash_set` (and other unordered
// associative containers known as the collection of Abseil "Swiss tables")
// contain other optimizations that result in both memory and computation
@@ -38,8 +38,9 @@
#include <type_traits>
#include "absl/algorithm/container.h"
+#include "absl/base/macros.h"
#include "absl/container/internal/hash_function_defaults.h" // IWYU pragma: export
-#include "absl/container/internal/node_hash_policy.h"
+#include "absl/container/internal/node_slot_policy.h"
#include "absl/container/internal/raw_hash_set.h" // IWYU pragma: export
#include "absl/memory/memory.h"
@@ -60,7 +61,7 @@ struct NodeHashSetPolicy;
// following notable differences:
//
// * Supports heterogeneous lookup, through `find()`, `operator[]()` and
-// `insert()`, provided that the map is provided a compatible heterogeneous
+// `insert()`, provided that the set 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 set.
@@ -73,16 +74,20 @@ struct NodeHashSetPolicy;
// absl/hash/hash.h for information on extending Abseil hashing to user-defined
// types.
//
+// Using `absl::node_hash_set` at interface boundaries in dynamically loaded
+// libraries (e.g. .dll, .so) is unsupported due to way `absl::Hash` values may
+// be randomized across dynamically loaded libraries.
+//
// Example:
//
// // Create a node hash set of three strings
-// absl::node_hash_map<std::string, std::string> ducks =
+// absl::node_hash_set<std::string> ducks =
// {"huey", "dewey", "louie"};
//
-// // Insert a new element into the node hash map
-// ducks.insert("donald"};
+// // Insert a new element into the node hash set
+// ducks.insert("donald");
//
-// // Force a rehash of the node hash map
+// // Force a rehash of the node hash set
// ducks.rehash(0);
//
// // See if "dewey" is present
@@ -100,7 +105,7 @@ class node_hash_set
public:
// Constructors and Assignment Operators
//
- // A node_hash_set supports the same overload set as `std::unordered_map`
+ // A node_hash_set supports the same overload set as `std::unordered_set`
// for construction and assignment:
//
// * Default constructor
@@ -167,7 +172,7 @@ class node_hash_set
// available within the `node_hash_set`.
//
// NOTE: this member function is particular to `absl::node_hash_set` and is
- // not provided in the `std::unordered_map` API.
+ // not provided in the `std::unordered_set` API.
using Base::capacity;
// node_hash_set::empty()
@@ -208,12 +213,16 @@ class node_hash_set
// `void`.
//
// NOTE: this return behavior is different than that of STL containers in
- // general and `std::unordered_map` in particular.
+ // general and `std::unordered_set` 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`.
+ // iterator pointing to `last`. The special case of calling
+ // `erase(begin(), end())` resets the reserved growth such that if
+ // `reserve(N)` has previously been called and there has been no intervening
+ // call to `clear()`, then after calling `erase(begin(), end())`, it is safe
+ // to assume that inserting N elements will not cause a rehash.
//
// size_type erase(const key_type& key):
//
@@ -314,7 +323,7 @@ class node_hash_set
// node_hash_set::merge()
//
- // Extracts elements from a given `source` flat hash map into this
+ // Extracts elements from a given `source` node hash set into this
// `node_hash_set`. If the destination `node_hash_set` already contains an
// element with an equivalent key, that element is not extracted.
using Base::merge;
@@ -322,15 +331,15 @@ class node_hash_set
// node_hash_set::swap(node_hash_set& other)
//
// Exchanges the contents of this `node_hash_set` with those of the `other`
- // flat hash map, avoiding invocation of any move, copy, or swap operations on
+ // node hash set, avoiding invocation of any move, copy, or swap operations on
// individual elements.
//
// All iterators and references on the `node_hash_set` remain valid, excepting
// for the past-the-end iterator, which is invalidated.
//
- // `swap()` requires that the flat hash set's hashing and key equivalence
- // functions be Swappable, and are exchaged using unqualified calls to
- // non-member `swap()`. If the map's allocator has
+ // `swap()` requires that the node hash set's hashing and key equivalence
+ // functions be Swappable, and are exchanged using unqualified calls to
+ // non-member `swap()`. If the set'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.
@@ -385,14 +394,14 @@ class node_hash_set
// node_hash_set::bucket_count()
//
// Returns the number of "buckets" within the `node_hash_set`. Note that
- // because a flat hash map contains all elements within its internal storage,
+ // because a node hash set contains all elements within its internal storage,
// this value simply equals the current capacity of the `node_hash_set`.
using Base::bucket_count;
// node_hash_set::load_factor()
//
// Returns the current load factor of the `node_hash_set` (the average number
- // of slots occupied with a value within the hash map).
+ // of slots occupied with a value within the hash set).
using Base::load_factor;
// node_hash_set::max_load_factor()
@@ -433,16 +442,18 @@ class node_hash_set
// erase_if(node_hash_set<>, Pred)
//
// Erases all elements that satisfy the predicate `pred` from the container `c`.
+// Returns the number of erased elements.
template <typename T, typename H, typename E, typename A, typename Predicate>
-void erase_if(node_hash_set<T, H, E, A>& c, Predicate pred) {
- container_internal::EraseIf(pred, &c);
+typename node_hash_set<T, H, E, A>::size_type erase_if(
+ node_hash_set<T, H, E, A>& c, Predicate pred) {
+ return container_internal::EraseIf(pred, &c);
}
namespace container_internal {
template <class T>
struct NodeHashSetPolicy
- : absl::container_internal::node_hash_policy<T&, NodeHashSetPolicy<T>> {
+ : absl::container_internal::node_slot_policy<T&, NodeHashSetPolicy<T>> {
using key_type = T;
using init_type = T;
using constant_iterators = std::true_type;