[ADT] Add 'consume_front' and 'consume_back' methods to StringRef which
are very handy when parsing text.
They are essentially a combination of startswith and a self-modifying
drop_front, or endswith and drop_back respectively.
Differential Revision: https://reviews.llvm.org/D22723
llvm-svn: 277288
diff --git a/llvm/unittests/ADT/StringRefTest.cpp b/llvm/unittests/ADT/StringRefTest.cpp
index 66e5944..7201886 100644
--- a/llvm/unittests/ADT/StringRefTest.cpp
+++ b/llvm/unittests/ADT/StringRefTest.cpp
@@ -322,6 +322,22 @@
EXPECT_FALSE(Str.startswith_lower("hi"));
}
+TEST(StringRefTest, ConsumeFront) {
+ StringRef Str("hello");
+ EXPECT_TRUE(Str.consume_front(""));
+ EXPECT_EQ("hello", Str);
+ EXPECT_TRUE(Str.consume_front("he"));
+ EXPECT_EQ("llo", Str);
+ EXPECT_FALSE(Str.consume_front("lloworld"));
+ EXPECT_EQ("llo", Str);
+ EXPECT_FALSE(Str.consume_front("lol"));
+ EXPECT_EQ("llo", Str);
+ EXPECT_TRUE(Str.consume_front("llo"));
+ EXPECT_EQ("", Str);
+ EXPECT_FALSE(Str.consume_front("o"));
+ EXPECT_TRUE(Str.consume_front(""));
+}
+
TEST(StringRefTest, EndsWith) {
StringRef Str("hello");
EXPECT_TRUE(Str.endswith(""));
@@ -341,6 +357,22 @@
EXPECT_FALSE(Str.endswith_lower("hi"));
}
+TEST(StringRefTest, ConsumeBack) {
+ StringRef Str("hello");
+ EXPECT_TRUE(Str.consume_back(""));
+ EXPECT_EQ("hello", Str);
+ EXPECT_TRUE(Str.consume_back("lo"));
+ EXPECT_EQ("hel", Str);
+ EXPECT_FALSE(Str.consume_back("helhel"));
+ EXPECT_EQ("hel", Str);
+ EXPECT_FALSE(Str.consume_back("hle"));
+ EXPECT_EQ("hel", Str);
+ EXPECT_TRUE(Str.consume_back("hel"));
+ EXPECT_EQ("", Str);
+ EXPECT_FALSE(Str.consume_back("h"));
+ EXPECT_TRUE(Str.consume_back(""));
+}
+
TEST(StringRefTest, Find) {
StringRef Str("hello");
EXPECT_EQ(2U, Str.find('l'));