str: Add trim()

3 files changed, 51 insertions, 0 deletions

diff --git a/src/str.cc b/src/str.cc
index bd7a654..44db3a6 100644
--- a/src/str.cc
+++ b/src/str.cc
@@ -6,6 +6,15 @@
 
 namespace str {
 
+namespace {
+
+[[nodiscard]]
+inline bool is_space(char c) {
+  return c == ' ' || c == '\t' || c == '\r' || c == '\n';
+}
+
+}  // namespace
+
 void split(std::string_view str, std::vector<std::string_view>& out,
            char separator, bool keep_empty) {
   out.clear();
@@ -31,4 +40,14 @@ std::vector<std::string_view> split(std::string_view str, char separator,
   return vec;
 }
 
+std::string_view trim(std::string_view str) {
+  size_t s = 0;
+  size_t e = str.size();
+  while (s < e && is_space(str[s]))
+    ++s;
+  while (e > s && is_space(str[e - 1]))
+    --e;
+  return str.substr(s, e - s);
+}
+
 }  // namespace str
diff --git a/src/str.hh b/src/str.hh
index 58d5d32..e1ee549 100644
--- a/src/str.hh
+++ b/src/str.hh
@@ -13,6 +13,9 @@ void split(std::string_view str, std::vector<std::string_view>& out,
                                                   char separator = ' ',
                                                   bool keep_empty = false);
 
+[[nodiscard]]
+std::string_view trim(std::string_view str);
+
 }  // namespace str
 
 #endif  // STR_HH
diff --git a/test/str.cc b/test/str.cc
index 1339bb0..6d7edf2 100644
--- a/test/str.cc
+++ b/test/str.cc
@@ -36,3 +36,32 @@ TEST(str, split) {
   EXPECT_EQ("a", ret[1]);
   EXPECT_EQ("b", ret[2]);
 }
+
+TEST(str, trim) {
+  auto ret = str::trim("");
+  EXPECT_EQ("", ret);
+
+  ret = str::trim(" ");
+  EXPECT_EQ("", ret);
+
+  ret = str::trim("  ");
+  EXPECT_EQ("", ret);
+
+  ret = str::trim("foo");
+  EXPECT_EQ("foo", ret);
+
+  ret = str::trim(" foo");
+  EXPECT_EQ("foo", ret);
+
+  ret = str::trim(" foo ");
+  EXPECT_EQ("foo", ret);
+
+  ret = str::trim("foo ");
+  EXPECT_EQ("foo", ret);
+
+  ret = str::trim("  foo bar           ");
+  EXPECT_EQ("foo bar", ret);
+
+  ret = str::trim("\tfoo bar\r\n");
+  EXPECT_EQ("foo bar", ret);
+}