From a07045fcc7b5e51385584bd80a89e4a08ba21c16 Mon Sep 17 00:00:00 2001
From: Martin Michelsen <fuzziqersoftware+g@gmail.com>
Date: Wed, 24 Apr 2024 21:13:22 -0700
Subject: [PATCH] add strip_multiline_comments

---
 src/Strings.hh     | 30 ++++++++++++++++++++++++++++++
 src/StringsTest.cc | 17 ++++++++++++++++-
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/src/Strings.hh b/src/Strings.hh
index ebc770e..289ecc0 100644
--- a/src/Strings.hh
+++ b/src/Strings.hh
@@ -73,6 +73,36 @@ void strip_whitespace(StrT& s) {
   }
 }
 
+template <typename StrT>
+void strip_multiline_comments(StrT& s, bool allow_unterminated = false) {
+  bool is_in_comment = false;
+  size_t write_offset = 0;
+  for (size_t z = 0; z < s.size();) {
+    if (!is_in_comment) {
+      if ((s[z] == '/') && (z + 1 < s.size()) && (s[z + 1] == '*')) {
+        is_in_comment = true;
+        z += 2;
+      } else {
+        s[write_offset++] = s[z++];
+      }
+    } else {
+      if ((s[z] == '*') && (z + 1 < s.size()) && (s[z + 1] == '/')) {
+        is_in_comment = false;
+        z += 2;
+      } else {
+        if (s[z++] == '\n') {
+          s[write_offset++] = '\n';
+        }
+      }
+    }
+  }
+  s.resize(write_offset);
+
+  if (!allow_unterminated && is_in_comment) {
+    throw std::runtime_error("unterminated multiline comment");
+  }
+}
+
 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 213eda1..aa13c6b 100644
--- a/src/StringsTest.cc
+++ b/src/StringsTest.cc
@@ -490,7 +490,6 @@ int main(int, char**) {
 
     string s = "abcdef";
     strip_whitespace(s);
-    fprintf(stderr, "%s\n", s.c_str());
     expect_eq(s, "abcdef");
 
     s = "abcdef\r\n";
@@ -514,6 +513,22 @@ int main(int, char**) {
     expect_eq(s, "");
   }
 
+  {
+    fprintf(stderr, "-- strip_multiline_comments\n");
+
+    string s = "abc/*def*/ghi";
+    strip_multiline_comments(s);
+    expect_eq(s, "abcghi");
+
+    s = "/*abc*/def\r\n";
+    strip_multiline_comments(s);
+    expect_eq(s, "def\r\n");
+
+    s = "abc\n/*def\nghi*/\njkl";
+    strip_multiline_comments(s);
+    expect_eq(s, "abc\n\n\njkl");
+  }
+
   {
     fprintf(stderr, "-- string_printf\n");
     string result = string_printf("%s %" PRIu64 " 0x%04hX", "lolz",