From: Eli Friedman <eli.friedman@gmail.com>
Date: Mon, 21 Dec 2009 06:49:24 +0000 (+0000)
Subject: Change StringRef::startswith and StringRef::endswith to versions which are a
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=d5b1f8a8426e82990dafc6e3336fefc6635c8fa4

Change StringRef::startswith and StringRef::endswith to versions which are a
bit more verbose, but optimize to much shorter code.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91817 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/ADT/StringRef.h b/include/llvm/ADT/StringRef.h
index f299f5fd651..a7442666d67 100644
--- a/include/llvm/ADT/StringRef.h
+++ b/include/llvm/ADT/StringRef.h
@@ -159,12 +159,14 @@ namespace llvm {
 
     /// startswith - Check if this string starts with the given \arg Prefix.
     bool startswith(StringRef Prefix) const {
-      return substr(0, Prefix.Length).equals(Prefix);
+      return Length >= Prefix.Length &&
+             memcmp(Data, Prefix.Data, Prefix.Length) == 0;
     }
 
     /// endswith - Check if this string ends with the given \arg Suffix.
     bool endswith(StringRef Suffix) const {
-      return slice(size() - Suffix.Length, size()).equals(Suffix);
+      return Length >= Suffix.Length &&
+             memcmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
     }
 
     /// @}
diff --git a/unittests/ADT/StringRefTest.cpp b/unittests/ADT/StringRefTest.cpp
index dfa208abefd..19665df88d5 100644
--- a/unittests/ADT/StringRefTest.cpp
+++ b/unittests/ADT/StringRefTest.cpp
@@ -198,6 +198,14 @@ TEST(StringRefTest, StartsWith) {
   EXPECT_FALSE(Str.startswith("hi"));
 }
 
+TEST(StringRefTest, EndsWith) {
+  StringRef Str("hello");
+  EXPECT_TRUE(Str.endswith("lo"));
+  EXPECT_FALSE(Str.endswith("helloworld"));
+  EXPECT_FALSE(Str.endswith("worldhello"));
+  EXPECT_FALSE(Str.endswith("so"));
+}
+
 TEST(StringRefTest, Find) {
   StringRef Str("hello");
   EXPECT_EQ(2U, Str.find('l'));