logic: implemented support for non-ascii characters in fulltext search

* fixed non-ascii characters not working in normal symbol search
* implemented support for non-ascii characters in fulltext search
* fixed fulltext search not working for symbols with lowest and highest character codes in a file
* using wstring in FullTextSearchIndex (causes this index to be dependent on text encoding selected in app settings)
* implemented rebuilding FullTextSearchIndex if used text encoding changed in app settings
* added utility lib

src/lib_utility/CMakeLists.txt

@@ -0,0 +1,7 @@
+
+add_files(
+	LIB_UTILITY_FILES
+
+	utility/TextCodec.cpp
+	utility/TextCodec.h
+)

src/lib_utility/utility/TextCodec.cpp

@@ -0,0 +1,46 @@
+#include "utility/TextCodec.h"
+
+#include <QTextCodec>
+
+TextCodec::TextCodec(const std::string& name)
+	: m_name(name)
+{
+}
+
+std::string TextCodec::getName() const
+{
+	return m_name;
+}
+
+bool TextCodec::isValid() const
+{
+	QTextCodec* codec = QTextCodec::codecForName(m_name.c_str());
+	if (codec)
+	{
+		return true;
+	}
+	return false;
+}
+
+std::wstring TextCodec::decode(const std::string& unicodeString) const
+{
+	QTextCodec* codec = QTextCodec::codecForName(m_name.c_str());
+	if (codec)
+	{
+		QTextDecoder decoder(codec);
+		return decoder.toUnicode(unicodeString.c_str()).toStdWString();
+	}
+	return QString::fromStdString(unicodeString).toStdWString();
+}
+
+std::string TextCodec::encode(const std::wstring& string) const
+{
+	QTextCodec* codec = QTextCodec::codecForName(m_name.c_str());
+	if (codec)
+	{
+		QTextEncoder encoder(codec);
+		return encoder.fromUnicode(QString::fromStdWString(string)).toStdString();
+	}
+
+	return QString::fromStdWString(string).toStdString();
+}

src/lib_utility/utility/TextCodec.h

@@ -0,0 +1,22 @@
+#ifndef TEXT_CODEC_H
+#define TEXT_CODEC_H
+
+#include <string>
+
+class TextCodec
+{
+public:
+	TextCodec(const std::string& name);
+
+	std::string getName() const;
+	bool isValid() const;
+
+	std::wstring decode(const std::string& unicodeString) const;
+
+	std::string encode(const std::wstring& string) const;
+
+private:
+	const std::string m_name;
+};
+
+#endif // TEXT_CODEC_H