Export of internal Abseil changes

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a7e789be4687681b98060fddbf8bd1c64a8f5908 by Abseil Team <absl-team@google.com>:

Support C++20 erase_if API in btree.

See the reference here: https://en.cppreference.com/w/cpp/container/set/erase_if.

PiperOrigin-RevId: 286235196

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952dd2fdd8435dd293e2186c97e14ef3f29a1aa6 by Derek Mauro <dmauro@google.com>:

Avoids accessing an out-of-bounds value during flag parsing

PiperOrigin-RevId: 286206167

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ba24591ade579fc4446a09bb3f23bf3602908c04 by Abseil Team <absl-team@google.com>:

Change null term* (and nul term*) to NUL-term* in comments.

PiperOrigin-RevId: 286066376

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d770baecf36f3d7a8214ca2033d90696ba353d00 by Andy Soffer <asoffer@google.com>:

cmake: Fix x86_64 check on Windows for random copts

Import of https://github.com/abseil/abseil-cpp/pull/518

PiperOrigin-RevId: 286056395

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9ed007e284ecf6ec79547437dbed9ce3023204b9 by Greg Falcon <gfalcon@google.com>:

Manual re-import of CCTZ from GitHub.  filegroup() moved as a side effect of an internal change.

PiperOrigin-RevId: 286015866

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25441cc5cb7ee906177f8dac0dcd524df0e6e305 by Derek Mauro <dmauro@google.com>:

Fix implicit cycle in debugging build rules due to .inc files

PiperOrigin-RevId: 285873346
GitOrigin-RevId: a7e789be4687681b98060fddbf8bd1c64a8f5908
Change-Id: Idef8cce4e723fccae6bdd749e94e11e655908214

absl/container/btree_map.h

@@ -412,6 +412,20 @@ void swap(btree_map<K, V, C, A> &x, btree_map<K, V, C, A> &y) {
   return x.swap(y);
 }
 
+// absl::erase_if(absl::btree_map<>, Pred)
+//
+// Erases all elements that satisfy the predicate pred from the container.
+template <typename K, typename V, typename C, typename A, typename Pred>
+void erase_if(btree_map<K, V, C, A> &map, Pred pred) {
+  for (auto it = map.begin(); it != map.end();) {
+    if (pred(*it)) {
+      it = map.erase(it);
+    } else {
+      ++it;
+    }
+  }
+}
+
 // absl::btree_multimap
 //
 // An `absl::btree_multimap<K, V>` is an ordered associative container of
@@ -701,6 +715,20 @@ void swap(btree_multimap<K, V, C, A> &x, btree_multimap<K, V, C, A> &y) {
   return x.swap(y);
 }
 
+// absl::erase_if(absl::btree_multimap<>, Pred)
+//
+// Erases all elements that satisfy the predicate pred from the container.
+template <typename K, typename V, typename C, typename A, typename Pred>
+void erase_if(btree_multimap<K, V, C, A> &map, Pred pred) {
+  for (auto it = map.begin(); it != map.end();) {
+    if (pred(*it)) {
+      it = map.erase(it);
+    } else {
+      ++it;
+    }
+  }
+}
+
 ABSL_NAMESPACE_END
 }  // namespace absl
 

absl/container/btree_set.h

@@ -360,6 +360,20 @@ void swap(btree_set<K, C, A> &x, btree_set<K, C, A> &y) {
   return x.swap(y);
 }
 
+// absl::erase_if(absl::btree_set<>, Pred)
+//
+// Erases all elements that satisfy the predicate pred from the container.
+template <typename K, typename C, typename A, typename Pred>
+void erase_if(btree_set<K, C, A> &set, Pred pred) {
+  for (auto it = set.begin(); it != set.end();) {
+    if (pred(*it)) {
+      it = set.erase(it);
+    } else {
+      ++it;
+    }
+  }
+}
+
 // absl::btree_multiset<>
 //
 // An `absl::btree_multiset<K>` is an ordered associative container of
@@ -649,6 +663,20 @@ void swap(btree_multiset<K, C, A> &x, btree_multiset<K, C, A> &y) {
   return x.swap(y);
 }
 
+// absl::erase_if(absl::btree_multiset<>, Pred)
+//
+// Erases all elements that satisfy the predicate pred from the container.
+template <typename K, typename C, typename A, typename Pred>
+void erase_if(btree_multiset<K, C, A> &set, Pred pred) {
+  for (auto it = set.begin(); it != set.end();) {
+    if (pred(*it)) {
+      it = set.erase(it);
+    } else {
+      ++it;
+    }
+  }
+}
+
 ABSL_NAMESPACE_END
 }  // namespace absl
 

absl/container/btree_test.cc

@@ -51,6 +51,7 @@ using ::absl::test_internal::InstanceTracker;
 using ::absl::test_internal::MovableOnlyInstance;
 using ::testing::ElementsAre;
 using ::testing::ElementsAreArray;
+using ::testing::IsEmpty;
 using ::testing::Pair;
 
 template <typename T, typename U>
@@ -2303,6 +2304,47 @@ TEST(Btree, EmptyTree) {
   EXPECT_GT(s.max_size(), 0);
 }
 
+bool IsEven(int k) { return k % 2 == 0; }
+
+TEST(Btree, EraseIf) {
+  // Test that erase_if works with all the container types and supports lambdas.
+  {
+    absl::btree_set<int> s = {1, 3, 5, 6, 100};
+    erase_if(s, [](int k) { return k > 3; });
+    EXPECT_THAT(s, ElementsAre(1, 3));
+  }
+  {
+    absl::btree_multiset<int> s = {1, 3, 3, 5, 6, 6, 100};
+    erase_if(s, [](int k) { return k <= 3; });
+    EXPECT_THAT(s, ElementsAre(5, 6, 6, 100));
+  }
+  {
+    absl::btree_map<int, int> m = {{1, 1}, {3, 3}, {6, 6}, {100, 100}};
+    erase_if(m, [](std::pair<const int, int> kv) { return kv.first > 3; });
+    EXPECT_THAT(m, ElementsAre(Pair(1, 1), Pair(3, 3)));
+  }
+  {
+    absl::btree_multimap<int, int> m = {{1, 1}, {3, 3}, {3, 6},
+                                        {6, 6}, {6, 7}, {100, 6}};
+    erase_if(m, [](std::pair<const int, int> kv) { return kv.second == 6; });
+    EXPECT_THAT(m, ElementsAre(Pair(1, 1), Pair(3, 3), Pair(6, 7)));
+  }
+  // Test that erasing all elements from a large set works and test support for
+  // function pointers.
+  {
+    absl::btree_set<int> s;
+    for (int i = 0; i < 1000; ++i) s.insert(2 * i);
+    erase_if(s, IsEven);
+    EXPECT_THAT(s, IsEmpty());
+  }
+  // Test that erase_if supports other format of function pointers.
+  {
+    absl::btree_set<int> s = {1, 3, 5, 6, 100};
+    erase_if(s, &IsEven);
+    EXPECT_THAT(s, ElementsAre(1, 3, 5));
+  }
+}
+
 }  // namespace
 }  // namespace container_internal
 ABSL_NAMESPACE_END