Added String::toUtf8/16/32 functions (#501)

include/SFML/System/String.hpp

@@ -264,6 +264,39 @@ public :
     ////////////////////////////////////////////////////////////
     std::wstring toWideString() const;
 
+    ////////////////////////////////////////////////////////////
+    /// \brief Convert the unicode string to a UTF-8 string
+    ///
+    /// \return Converted UTF-8 string
+    ///
+    /// \see toUtf16, toUtf32
+    ///
+    ////////////////////////////////////////////////////////////
+    std::basic_string<Uint8> toUtf8() const;
+
+    ////////////////////////////////////////////////////////////
+    /// \brief Convert the unicode string to a UTF-16 string
+    ///
+    /// \return Converted UTF-16 string
+    ///
+    /// \see toUtf8, toUtf32
+    ///
+    ////////////////////////////////////////////////////////////
+    std::basic_string<Uint16> toUtf16() const;
+
+    ////////////////////////////////////////////////////////////
+    /// \brief Convert the unicode string to a UTF-32 string
+    ///
+    /// This function doesn't perform any conversion, since the
+    /// string is already stored as UTF-32 internally.
+    ///
+    /// \return Converted UTF-32 string
+    ///
+    /// \see toUtf8, toUtf16
+    ///
+    ////////////////////////////////////////////////////////////
+    std::basic_string<Uint32> toUtf32() const;
+
     ////////////////////////////////////////////////////////////
     /// \brief Overload of assignment operator
     ///

src/SFML/System/String.cpp

@@ -174,6 +174,41 @@ std::wstring String::toWideString() const
 }
 
 
+////////////////////////////////////////////////////////////
+std::basic_string<Uint8> String::toUtf8() const
+{
+    // Prepare the output string
+    std::basic_string<Uint8> output;
+    output.reserve(m_string.length());
+
+    // Convert
+    Utf32::toUtf8(m_string.begin(), m_string.end(), std::back_inserter(output));
+
+    return output;
+}
+
+
+////////////////////////////////////////////////////////////
+std::basic_string<Uint16> String::toUtf16() const
+{
+    // Prepare the output string
+    std::basic_string<Uint16> output;
+    output.reserve(m_string.length());
+
+    // Convert
+    Utf32::toUtf16(m_string.begin(), m_string.end(), std::back_inserter(output));
+
+    return output;
+}
+
+
+////////////////////////////////////////////////////////////
+std::basic_string<Uint32> String::toUtf32() const
+{
+    return m_string;
+}
+
+
 ////////////////////////////////////////////////////////////
 String& String::operator =(const String& right)
 {