Extract string conversion functions from SettingsBag.

It's useful to have this functionality elsewhere, especially
the string to bool one which I'm going to use in the next
commit.

src/kamokan_impl/CMakeLists.txt

@@ -19,6 +19,7 @@ add_library(${PROJECT_NAME} STATIC
 	error_response.cpp
 	quick_submit_paste_response.cpp
 	storage.cpp
+	string_conv.cpp
 )
 
 target_include_directories(${PROJECT_NAME}

src/kamokan_impl/settings_bag.cpp

@@ -21,7 +21,6 @@
 #include <ciso646>
 #include <cassert>
 #include <cstdint>
-#include <sstream>
 #include <iostream>
 
 namespace kamokan {
@@ -60,41 +59,4 @@ namespace kamokan {
 		assert(m_defaults.find(parKey) == m_defaults.end());
 		m_defaults[parKey] = parValue;
 	}
-
-	template <>
-	std::string SettingsBag::as (boost::string_view parIndex) const {
-		auto& setting = this->at(parIndex);
-		return std::string(setting);
-	}
-
-	template <>
-	bool SettingsBag::as (boost::string_view parIndex) const {
-		auto& setting = this->at(parIndex);
-		if (setting == "true" or setting == "yes" or setting == "1" or setting == "on") {
-			return true;
-		}
-		else if (setting == "false" or setting == "no" or setting == "0" or setting == "off") {
-			return false;
-		}
-		else {
-			std::ostringstream oss;
-			oss << "Bad conversion: can't convert \"" << setting << "\" to bool";
-			throw std::runtime_error(oss.str());
-		}
-	}
-
-	template <>
-	uint16_t SettingsBag::as (boost::string_view parIndex) const {
-		return dhandy::lexical_cast<uint16_t>(this->at(parIndex));
-	}
-
-	template <>
-	uint32_t SettingsBag::as (boost::string_view parIndex) const {
-		return dhandy::lexical_cast<uint32_t>(this->at(parIndex));
-	}
-
-	template std::string SettingsBag::as<std::string> (boost::string_view parIndex) const;
-	template bool SettingsBag::as<bool> (boost::string_view parIndex) const;
-	template uint16_t SettingsBag::as<uint16_t> (boost::string_view parIndex) const;
-	template uint32_t SettingsBag::as<uint32_t> (boost::string_view parIndex) const;
 } //namespace kamokan

src/kamokan_impl/settings_bag.hpp

@@ -22,6 +22,7 @@
 #if defined(SPDLOG_DEBUG_ON)
 #	include "spdlog.hpp"
 #endif
+#include "string_conv.hpp"
 #include <map>
 #include <boost/utility/string_view.hpp>
 #include <functional>
@@ -45,9 +46,9 @@ namespace kamokan {
 		const IniFile::KeyValueMapType* m_values;
 	};
 
-	template <>
-	inline boost::string_view SettingsBag::as (boost::string_view parIndex) const {
-		return (*this)[parIndex];
+	template <typename T>
+	inline T SettingsBag::as (boost::string_view parIndex) const {
+		return string_conv<T>(this->at(parIndex));
 	}
 
 	inline const boost::string_view& SettingsBag::at (boost::string_view parIndex) const {

src/kamokan_impl/string_conv.cpp

@@ -0,0 +1,38 @@
+/* Copyright 2017, Michele Santullo
+ * This file is part of "kamokan".
+ *
+ * "kamokan" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "kamokan" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "kamokan".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "string_conv.hpp"
+#include <sstream>
+
+namespace kamokan {
+	template <>
+	bool string_conv (boost::string_view parStr) {
+		if (parStr == "true" or parStr == "yes" or parStr == "1" or parStr == "on") {
+			return true;
+		}
+		else if (parStr == "false" or parStr == "no" or parStr == "0" or parStr == "off") {
+			return false;
+		}
+		else {
+			std::ostringstream oss;
+			oss << "Bad conversion: can't convert \"" << parStr << "\" to bool";
+			throw std::runtime_error(oss.str());
+		}
+	}
+
+	template bool string_conv<bool> (boost::string_view parStr);
+} //namespace kamokan

src/kamokan_impl/string_conv.hpp

@@ -0,0 +1,58 @@
+/* Copyright 2017, Michele Santullo
+ * This file is part of "kamokan".
+ *
+ * "kamokan" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "kamokan" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "kamokan".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "duckhandy/lexical_cast.hpp"
+#include <boost/utility/string_view.hpp>
+#include <type_traits>
+#include <cstdint>
+#include <string>
+
+namespace kamokan {
+	template <typename T>
+	[[gnu::pure]]
+	T string_conv (boost::string_view parStr);
+
+	template <>
+	[[gnu::pure]]
+	bool string_conv (boost::string_view parStr);
+
+	template <>
+	[[gnu::always_inline]] inline
+	boost::string_view string_conv (boost::string_view parStr) {
+		return parStr;
+	}
+
+	template <>
+	[[gnu::pure,gnu::always_inline]] inline
+	uint16_t string_conv (boost::string_view parStr) {
+		return dhandy::lexical_cast<uint16_t>(parStr);
+	}
+
+	template <>
+	[[gnu::pure,gnu::always_inline]] inline
+	uint32_t string_conv (boost::string_view parStr) {
+		return dhandy::lexical_cast<uint32_t>(parStr);
+	}
+
+	template <>
+	inline
+	std::string string_conv (boost::string_view parStr) {
+		return std::string(parStr.data(), parStr.size());
+	}
+} //namespace kamokan