Export of internal Abseil changes.

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714347c156cfe01575c1830a92bc6dea3030065b by Emma Christie <emmachristie@google.com>:

Release absl::EqualsIgnoreCase

PiperOrigin-RevId: 216243900

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688106e2b9d2924799d597682690851cfba87818 by Abseil Team <absl-team@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 216208373

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53638e4da238b230af0e56dc31b9fb790e708f36 by Emma Christie <emmachristie@google.com>:

Update StartsWithIgnoreCase(), EndsWithIgnoreCase(), and EqualsIgnoreCase() headers to say that these functions only consider ASCII case inputs.

PiperOrigin-RevId: 215930962
GitOrigin-RevId: 714347c156cfe01575c1830a92bc6dea3030065b
Change-Id: I7fb3506234185b1a961e0110c1f8302ffe7228fa

3 files changed, 28 insertions, 4 deletions

diff --git a/absl/strings/match.cc b/absl/strings/match.cc
index 25bd7f0b828b..3d10c57784eb 100644
--- a/absl/strings/match.cc
+++ b/absl/strings/match.cc
@@ -27,6 +27,13 @@ bool CaseEqual(absl::string_view piece1, absl::string_view piece2) {
 }
 }  // namespace
 
+bool EqualsIgnoreCase(absl::string_view piece1, absl::string_view piece2) {
+  return (piece1.size() == piece2.size() &&
+          0 == absl::strings_internal::memcasecmp(piece1.data(), piece2.data(),
+                                                  piece1.size()));
+  // memcasecmp uses absl::ascii_tolower().
+}
+
 bool StartsWithIgnoreCase(absl::string_view text, absl::string_view prefix) {
   return (text.size() >= prefix.size()) &&
          CaseEqual(text.substr(0, prefix.size()), prefix);
diff --git a/absl/strings/match.h b/absl/strings/match.h
index 942a196b8853..6e8ed10fc50f 100644
--- a/absl/strings/match.h
+++ b/absl/strings/match.h
@@ -66,16 +66,22 @@ inline bool EndsWith(absl::string_view text, absl::string_view suffix) {
          );
 }
 
-// StartsWithIgnoreCase()
+// EqualsIgnoreCase()
 //
-// Returns whether a given string `text` starts with `starts_with`, ignoring
+// Returns whether given ASCII strings `piece1` and `piece2` are equal, ignoring
 // case in the comparison.
+bool EqualsIgnoreCase(absl::string_view piece1, absl::string_view piece2);
+
+// StartsWithIgnoreCase()
+//
+// Returns whether a given ASCII string `text` starts with `starts_with`,
+// ignoring case in the comparison.
 bool StartsWithIgnoreCase(absl::string_view text, absl::string_view prefix);
 
 // EndsWithIgnoreCase()
 //
-// Returns whether a given string `text` ends with `ends_with`, ignoring case
-// in the comparison.
+// Returns whether a given ASCII string `text` ends with `ends_with`, ignoring
+// case in the comparison.
 bool EndsWithIgnoreCase(absl::string_view text, absl::string_view suffix);
 
 }  // namespace absl
diff --git a/absl/strings/match_test.cc b/absl/strings/match_test.cc
index d194f0e689bf..c21e00bf807c 100644
--- a/absl/strings/match_test.cc
+++ b/absl/strings/match_test.cc
@@ -80,6 +80,17 @@ TEST(MatchTest, ContainsNull) {
   EXPECT_FALSE(absl::StrContains(cs, sv2));
 }
 
+TEST(MatchTest, EqualsIgnoreCase) {
+  std::string text = "the";
+  absl::string_view data(text);
+
+  EXPECT_TRUE(absl::EqualsIgnoreCase(data, "The"));
+  EXPECT_TRUE(absl::EqualsIgnoreCase(data, "THE"));
+  EXPECT_TRUE(absl::EqualsIgnoreCase(data, "the"));
+  EXPECT_FALSE(absl::EqualsIgnoreCase(data, "Quick"));
+  EXPECT_FALSE(absl::EqualsIgnoreCase(data, "then"));
+}
+
 TEST(MatchTest, StartsWithIgnoreCase) {
   EXPECT_TRUE(absl::StartsWithIgnoreCase("foo", "foo"));
   EXPECT_TRUE(absl::StartsWithIgnoreCase("foo", "Fo"));