ircd::spirit: Optimize boost::spirit::qi::char_parser / literal_char related.

include/ircd/spirit/boost.h

@@ -41,7 +41,8 @@
 #include <boost/spirit/include/phoenix.hpp>
 #include <boost/spirit/repository/include/qi_seek.hpp>
 #include <boost/spirit/repository/include/qi_subrule.hpp>
-
+#include "char.h"
 #pragma GCC visibility pop
+
 #pragma clang attribute pop
 #pragma clang attribute pop

include/ircd/spirit/char.h

@@ -0,0 +1,113 @@
+// The Construct
+//
+// Copyright (C) The Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#if defined(__clang__)
+template<class Derived>
+struct [[clang::internal_linkage, gnu::visibility("internal")]]
+boost::spirit::qi::char_parser
+<
+	Derived,
+	typename boost::spirit::char_encoding::standard::char_type,
+	typename boost::mpl::if_c<true, boost::spirit::unused_type, typename boost::spirit::char_encoding::standard::char_type>::type
+>
+:primitive_parser
+<
+	literal_char<char_encoding::standard, true, false>
+>
+{
+	using CharEncoding = boost::spirit::char_encoding::standard;
+	using char_type = typename CharEncoding::char_type;
+	struct char_parser_id;
+
+	template<class Context,
+	         class Iterator>
+	struct attribute
+	{
+		using type = char_type;
+	};
+
+	template<class Iterator,
+	         class Context,
+	         class Skipper,
+	         class Attribute>
+	[[gnu::hot]]
+	bool parse(Iterator &__restrict__ start, const Iterator &__restrict__ stop, Context &c, const Skipper &s, Attribute &a) const noexcept
+	{
+		qi::skip_over(start, stop, s);
+		if(likely(start != stop))
+		{
+			if(this->derived().test(*start, c))
+			{
+				spirit::traits::assign_to(*start, a);
+				++start;
+				return true;
+			}
+			else return false;
+		}
+		else return false;
+	}
+};
+#endif
+
+#if defined(__clang__)
+template<>
+struct [[clang::internal_linkage, gnu::visibility("internal")]]
+boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>
+:char_parser
+<
+	literal_char<char_encoding::standard, true, false>,
+    typename char_encoding::standard::char_type,
+	typename mpl::if_c<true, unused_type, typename char_encoding::standard::char_type>::type
+>
+{
+	using CharEncoding = boost::spirit::char_encoding::standard;
+	using char_type = typename CharEncoding::char_type;
+	using char_encoding = CharEncoding;
+
+	template<class Context,
+	         class Iterator>
+	struct attribute
+	{
+		using type = typename mpl::if_c<true, unused_type, char_type>::type;
+	};
+
+  private:
+	char_type ch;
+
+  public:
+	template<class CharParam,
+	         class Context>
+	[[gnu::hot]]
+	bool test(CharParam ch, Context &) const
+	{
+		static_assert(std::is_same<CharParam, char_type>::value);
+
+		#ifdef RB_DEBUG
+		ircd::always_assert(traits::ischar<CharParam, char_encoding>::call(ch));
+		#endif
+
+		return this->ch == char_type(ch);
+	}
+
+	template<class Context>
+	info what(Context &) const
+	{
+		return info
+		{
+			"literal-char", char_encoding::toucs4(ch)
+		};
+	}
+
+	template<class Char>
+	literal_char(Char ch)
+	:ch(static_cast<char_type>(ch))
+	{}
+};
+#endif