Add `c_contains()` and `c_contains_subrange()` to `absl/algorithm/container.h`.

These functions are based on the C++23's `std::ranges::contains()` and `std::ranges::contains_subrange()` functions, see: https://en.cppreference.com/w/cpp/algorithm/ranges/contains

PiperOrigin-RevId: 647084955
Change-Id: If5a01784e3cf1cc4d88e7f2fef92a3701fafc886

1 files changed, 16 insertions, 0 deletions

diff --git a/absl/algorithm/container_test.cc b/absl/algorithm/container_test.cc
index c01f5fc0..7e54e2b2 100644
--- a/absl/algorithm/container_test.cc
+++ b/absl/algorithm/container_test.cc
@@ -113,6 +113,11 @@ TEST_F(NonMutatingTest, FindReturnsCorrectType) {
   absl::c_find(absl::implicit_cast<const std::list<int>&>(sequence_), 3);
 }
 
+TEST_F(NonMutatingTest, Contains) {
+  EXPECT_TRUE(absl::c_contains(container_, 3));
+  EXPECT_FALSE(absl::c_contains(container_, 4));
+}
+
 TEST_F(NonMutatingTest, FindIf) { absl::c_find_if(container_, Predicate); }
 
 TEST_F(NonMutatingTest, FindIfNot) {
@@ -305,6 +310,17 @@ TEST_F(NonMutatingTest, SearchWithPredicate) {
   absl::c_search(vector_, sequence_, BinPredicate);
 }
 
+TEST_F(NonMutatingTest, ContainsSubrange) {
+  EXPECT_TRUE(absl::c_contains_subrange(sequence_, vector_));
+  EXPECT_TRUE(absl::c_contains_subrange(vector_, sequence_));
+  EXPECT_TRUE(absl::c_contains_subrange(array_, sequence_));
+}
+
+TEST_F(NonMutatingTest, ContainsSubrangeWithPredicate) {
+  EXPECT_TRUE(absl::c_contains_subrange(sequence_, vector_, Equals));
+  EXPECT_TRUE(absl::c_contains_subrange(vector_, sequence_, Equals));
+}
+
 TEST_F(NonMutatingTest, SearchN) { absl::c_search_n(sequence_, 3, 1); }
 
 TEST_F(NonMutatingTest, SearchNWithPredicate) {