From 800bdbb18617dfac36067b8841781a92b19d57c1 Mon Sep 17 00:00:00 2001
From: Joel Klinghed <the_jk@spawned.biz>
Date: Sun, 19 Oct 2025 00:06:54 +0200
Subject: str: Add ltrim and rtrim

Useful when you only want to trim one side..
---
 src/str.cc  | 15 +++++++++++++++
 src/str.hh  |  6 ++++++
 test/str.cc | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 79 insertions(+)

diff --git a/src/str.cc b/src/str.cc
index e5b70ed..129e0f3 100644
--- a/src/str.cc
+++ b/src/str.cc
@@ -76,4 +76,19 @@ std::string_view trim(std::string_view str) {
   return str.substr(s, e - s);
 }
 
+std::string_view ltrim(std::string_view str) {
+  size_t s = 0;
+  size_t const e = str.size();
+  while (s < e && is_space(str[s]))
+    ++s;
+  return str.substr(s, e - s);
+}
+
+std::string_view rtrim(std::string_view str) {
+  size_t e = str.size();
+  while (e > 0 && is_space(str[e - 1]))
+    --e;
+  return str.substr(0, e);
+}
+
 }  // namespace str
diff --git a/src/str.hh b/src/str.hh
index 1c618ee..c736f4b 100644
--- a/src/str.hh
+++ b/src/str.hh
@@ -23,6 +23,12 @@ void split(std::string_view str, std::vector<std::string_view>& out,
 [[nodiscard]]
 std::string_view trim(std::string_view str);
 
+[[nodiscard]]
+std::string_view ltrim(std::string_view str);
+
+[[nodiscard]]
+std::string_view rtrim(std::string_view str);
+
 }  // namespace str
 
 #endif  // STR_HH
diff --git a/test/str.cc b/test/str.cc
index 6d7edf2..d7d331f 100644
--- a/test/str.cc
+++ b/test/str.cc
@@ -65,3 +65,61 @@ TEST(str, trim) {
   ret = str::trim("\tfoo bar\r\n");
   EXPECT_EQ("foo bar", ret);
 }
+
+TEST(str, ltrim) {
+  auto ret = str::ltrim("");
+  EXPECT_EQ("", ret);
+
+  ret = str::ltrim(" ");
+  EXPECT_EQ("", ret);
+
+  ret = str::ltrim("  ");
+  EXPECT_EQ("", ret);
+
+  ret = str::ltrim("foo");
+  EXPECT_EQ("foo", ret);
+
+  ret = str::ltrim(" foo");
+  EXPECT_EQ("foo", ret);
+
+  ret = str::ltrim(" foo ");
+  EXPECT_EQ("foo ", ret);
+
+  ret = str::ltrim("foo ");
+  EXPECT_EQ("foo ", ret);
+
+  ret = str::ltrim("  foo bar           ");
+  EXPECT_EQ("foo bar           ", ret);
+
+  ret = str::ltrim("\tfoo bar\r\n");
+  EXPECT_EQ("foo bar\r\n", ret);
+}
+
+TEST(str, rtrim) {
+  auto ret = str::rtrim("");
+  EXPECT_EQ("", ret);
+
+  ret = str::rtrim(" ");
+  EXPECT_EQ("", ret);
+
+  ret = str::rtrim("  ");
+  EXPECT_EQ("", ret);
+
+  ret = str::rtrim("foo");
+  EXPECT_EQ("foo", ret);
+
+  ret = str::rtrim(" foo");
+  EXPECT_EQ(" foo", ret);
+
+  ret = str::rtrim(" foo ");
+  EXPECT_EQ(" foo", ret);
+
+  ret = str::rtrim("foo ");
+  EXPECT_EQ("foo", ret);
+
+  ret = str::rtrim("  foo bar           ");
+  EXPECT_EQ("  foo bar", ret);
+
+  ret = str::rtrim("\tfoo bar\r\n");
+  EXPECT_EQ("\tfoo bar", ret);
+}
-- 
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