From 7512997cc085cc3b0991d5193d36e00357795850 Mon Sep 17 00:00:00 2001
From: Martin Michelsen <fuzziqersoftware+g@gmail.com>
Date: Sat, 13 Apr 2024 10:28:10 -0700
Subject: [PATCH] add strip_whitespace

---
 src/Strings.hh     | 17 +++++++++++++++++
 src/StringsTest.cc | 29 +++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/src/Strings.hh b/src/Strings.hh
index 614f086..afeac0c 100644
--- a/src/Strings.hh
+++ b/src/Strings.hh
@@ -57,6 +57,23 @@ void strip_leading_whitespace(StrT& s) {
   }
 }
 
+template <typename StrT>
+void strip_whitespace(StrT& s) {
+  size_t start_index = s.find_first_not_of(" \t\r\n");
+  size_t end_index = s.find_last_not_of(" \t\r\n");
+  fprintf(stderr, "%zu %zu\n", start_index, end_index);
+  if (start_index != StrT::npos && end_index != StrT::npos) {
+    if (start_index) {
+      s = s.substr(start_index, end_index - start_index + 1);
+    } else {
+      s.resize(end_index + 1);
+    }
+  } else if (!s.empty() &&
+      ((s[0] == ' ') || (s[0] == '\t') || (s[0] == '\r') || (s[0] == '\n'))) {
+    s.resize(0); // String is entirely whitespace
+  }
+}
+
 std::string escape_quotes(const std::string& s);
 std::string escape_url(const std::string& s, bool escape_slash = false);
 
diff --git a/src/StringsTest.cc b/src/StringsTest.cc
index 451d3ea..213eda1 100644
--- a/src/StringsTest.cc
+++ b/src/StringsTest.cc
@@ -485,6 +485,35 @@ int main(int, char**) {
     expect_eq(s5, "");
   }
 
+  {
+    fprintf(stderr, "-- strip_whitespace\n");
+
+    string s = "abcdef";
+    strip_whitespace(s);
+    fprintf(stderr, "%s\n", s.c_str());
+    expect_eq(s, "abcdef");
+
+    s = "abcdef\r\n";
+    strip_whitespace(s);
+    expect_eq(s, "abcdef");
+
+    s = "  \nabc\tdef";
+    strip_whitespace(s);
+    expect_eq(s, "abc\tdef");
+
+    s = "  \nabc\tdef  \r\n";
+    strip_whitespace(s);
+    expect_eq(s, "abc\tdef");
+
+    s = "";
+    strip_whitespace(s);
+    expect_eq(s, "");
+
+    s = "   \t\r\n  ";
+    strip_whitespace(s);
+    expect_eq(s, "");
+  }
+
   {
     fprintf(stderr, "-- string_printf\n");
     string result = string_printf("%s %" PRIu64 " 0x%04hX", "lolz",