fixes

include/util/line_parser.hpp

@@ -0,0 +1,87 @@
+#pragma once
+
+#include <string>
+#include <string_view>
+#include <istream>
+#include "util/for_each.hpp"
+
+namespace ztu
+{
+template<bool Repeating, typename F>
+struct prefixed_line_parser {
+	const std::string_view prefix;
+	F parse;
+};
+
+template<bool Repeating>
+struct line_repeating_type {};
+
+static constexpr auto is_repeating = line_repeating_type<true>{};
+static constexpr auto is_not_repeating = line_repeating_type<false>{};
+
+template<bool Repeating, typename F>
+prefixed_line_parser<Repeating, F> make_line_parser(std::string_view prefix, line_repeating_type<Repeating>, F&& f)
+{
+	return { prefix, std::forward<F>(f) };
+}
+
+template<typename E, bool... Rs, class... Fs>
+E parse_lines(std::istream& in, const bool pedantic, prefixed_line_parser<Rs, Fs>&&... parsers)
+{
+
+	auto ec = E{};
+
+	std::string line;
+	while (std::getline(in, line)) [[likely]]
+	{
+		parse_current_line:
+
+		auto line_updated = false;
+
+		for_each::argument(
+			[&]<bool R, typename F>(prefixed_line_parser<R, F>&& parser) -> bool
+			{
+				if (line.starts_with(parser.prefix))
+				{
+					const auto prefix_length = parser.prefix.length();
+					ec = parser.parse(line.substr(prefix_length));
+
+					if constexpr (R)
+					{
+						while (std::getline(in, line))
+						{
+							if (line.starts_with(parser.prefix)) [[likely]]
+							{
+								ec = parser.parse(line.substr(prefix_length));
+							}
+							else [[unlikely]]
+							{
+								line_updated = true;
+								break;
+							}
+						}
+					}
+
+					return true;
+				}
+
+				return false;
+			},
+			std::forward<prefixed_line_parser<Rs, Fs>>(parsers)...
+		);
+
+		if (pedantic) {
+			if (ec != E{}) [[unlikely]] {
+				return ec;
+			}
+		}
+
+		if (line_updated)
+		{
+			goto parse_current_line;
+		}
+	}
+
+	return E{};
+}
+}