From b7f8d73d95b5892a6565dc539028e7113eb42e85 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Mon, 2 May 2022 14:26:06 +1000
Subject: [PATCH] string: add lstrip, rstrip, strip

---
 string.hpp      | 23 +++++++++++++++++++++++
 test/string.cpp | 26 ++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/string.hpp b/string.hpp
index 64a5f0d1..d6dc8ee6 100644
--- a/string.hpp
+++ b/string.hpp
@@ -101,6 +101,29 @@ namespace cruft {
     {
         return transform (val, ::tolower);
     }
+
+
+    inline std::string_view
+    lstrip (std::string_view str)
+    {
+        auto const pos = std::find_if_not (std::begin (str), std::end (str), ascii::is_space);
+        return { pos, std::end (str) };
+    }
+
+
+    inline std::string_view
+    rstrip (std::string_view str)
+    {
+        auto const pos = std::find_if_not (std::rbegin (str), std::rend (str), ascii::is_space);
+        return { str.begin (), pos.base () };
+    }
+
+
+    inline std::string_view
+    strip (std::string_view str)
+    {
+        return lstrip (rstrip (str));
+    }
 }
 
 
diff --git a/test/string.cpp b/test/string.cpp
index e9ff3424..2d7e388f 100644
--- a/test/string.cpp
+++ b/test/string.cpp
@@ -287,6 +287,31 @@ void test_equality_lower (cruft::TAP::logger &tap)
 }
 
 
+///////////////////////////////////////////////////////////////////////////////
+static void
+test_strip (cruft::TAP::logger &tap)
+{
+    static constexpr struct {
+        char const *val;
+        char const *expected_l;
+        char const *expected_r;
+        char const *msg;
+    } TESTS[] = {
+        { "asdf", "asdf", "asdf", "no stripping" },
+        { "", "", "", "empty string" },
+        { " ", "", "", "only space" },
+        { " \nasdf", "asdf", " \nasdf", "left space" },
+        { "asdf \n", "asdf \n", "asdf", "right space" },
+        { " asdf ", "asdf ", " asdf", "both space" },
+    };
+
+    for (auto const &t: TESTS) {
+        tap.expect_eq (t.expected_l, cruft::lstrip (t.val), "lstrip: {}", t.msg);
+        tap.expect_eq (t.expected_r, cruft::rstrip (t.val), "rstrip: {}", t.msg);
+    }
+}
+
+
 ///////////////////////////////////////////////////////////////////////////////
 int
 main (int, char**)
@@ -301,6 +326,7 @@ main (int, char**)
     test_comparator_less (tap);
     test_less_lower (tap);
     test_equality_lower (tap);
+    test_strip (tap);
 
     return tap.status ();
 }
\ No newline at end of file