Add indentation C comment heuristics

See foonathan/standardese#84.

src/libclang/preprocessor.cpp

@@ -202,6 +202,7 @@ namespace
             {
                 *result_ += "#line " + std::to_string(line) + "\n";
                 cur_line_   = line;
+                cur_column_ = 0;
             }
         }
 
@@ -212,8 +213,13 @@ namespace
             for (auto c : str)
             {
                 *result_ += c;
+                ++cur_column_;
+
                 if (c == '\n')
+                {
                     ++cur_line_;
+                    cur_column_ = 0;
+                }
             }
         }
 
@@ -222,8 +228,13 @@ namespace
             if (write_ == true)
             {
                 result_->push_back(*ptr_);
+                ++cur_column_;
+
                 if (*ptr_ == '\n')
+                {
                     ++cur_line_;
+                    cur_column_ = 0;
+                }
             }
             ++ptr_;
         }
@@ -247,10 +258,15 @@ namespace
 
         void skip_with_linecount() noexcept
         {
-            if (*ptr_ == '\n' && write_ == true)
+            if (write_ == true)
+            {
+                ++cur_column_;
+                if (*ptr_ == '\n')
                 {
                     result_->push_back('\n');
                     ++cur_line_;
+                    cur_column_ = 0;
+                }
             }
 
             ++ptr_;
@@ -281,6 +297,11 @@ namespace
             return cur_line_;
         }
 
+        unsigned cur_column() const noexcept
+        {
+            return cur_column_;
+        }
+
         bool was_newl() const noexcept
         {
             return result_->empty() || result_->back() == '\n';
@@ -288,7 +309,7 @@ namespace
 
     private:
         ts::object_ref<std::string> result_;
-        unsigned                    cur_line_;
+        unsigned                    cur_line_, cur_column_;
         const char*                 ptr_;
         ts::flag                    write_;
     };
@@ -398,9 +419,14 @@ namespace
         detail::pp_doc_comment result;
         result.kind = detail::pp_doc_comment::c;
 
+        auto indent = p.cur_column() + 3;
+
         if (starts_with(p, " "))
+        {
             // skip one whitespace at most
             p.skip();
+            ++indent;
+        }
 
         while (!starts_with(p, "*/"))
         {
@@ -415,8 +441,16 @@ namespace
                 result.comment += '\n';
 
                 // skip indentation
-                while (starts_with(p, " "))
+                for (auto i = 0u; i < indent && starts_with(p, " "); ++i)
                     p.skip();
+
+                auto extra_indent = 0u;
+                while (starts_with(p, " "))
+                {
+                    ++extra_indent;
+                    p.skip();
+                }
+
                 // skip continuation star, if any
                 if (starts_with(p, "*") && !starts_with(p, "*/"))
                 {
@@ -425,6 +459,11 @@ namespace
                         // skip one whitespace at most
                         p.skip();
                 }
+                else
+                {
+                    // insert extra indent again
+                    result.comment += std::string(extra_indent, ' ');
+                }
             }
             else
             {

test/cpp_preprocessor.cpp

@@ -186,6 +186,52 @@ lines
     REQUIRE((file->unmatched_comments().size() == 6u + 1u));
 }
 
+TEST_CASE("comment content")
+{
+    auto code = R"(
+/// simple comment
+
+///no space
+
+/// multi
+/// line
+/// comment
+
+/** C comment */
+/**C comment no space*/
+
+/** Multiline
+C
+comment */
+
+    /** Multiline
+        C
+         comment
+          with
+           indent */
+
+    /** Multiline
+            * C
+            * comment
+            * with
+            * indent
+            * star */
+)";
+
+    auto file     = parse({}, "comment-content.cpp", code);
+    auto comments = file->unmatched_comments();
+    REQUIRE((comments.size() == 8u));
+
+    REQUIRE(comments[0u].content == "simple comment");
+    REQUIRE(comments[1u].content == "no space");
+    REQUIRE(comments[2u].content == "multi\nline\ncomment");
+    REQUIRE(comments[3u].content == "C comment");
+    REQUIRE(comments[4u].content == "C comment no space");
+    REQUIRE(comments[5u].content == "Multiline\nC\ncomment");
+    REQUIRE(comments[6u].content == "Multiline\nC\n comment\n  with\n   indent");
+    REQUIRE(comments[7u].content == "Multiline\nC\ncomment\nwith\nindent\nstar");
+}
+
 TEST_CASE("comment matching")
 {
     auto code = R"(