MyGUI_UString.cpp

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/*
 * This source file is part of MyGUI. For the latest info, see http://mygui.info/
 * Distributed under the MIT License
 * (See accompanying file COPYING.MIT or copy at http://opensource.org/licenses/MIT)
 */
 
#include "MyGUI_Precompiled.h"
#include "MyGUI_UString.h"
 
namespace MyGUI
{
 
    //--------------------------------------------------------------------------
    UString::_base_iterator::_base_iterator()
    {
        mString = nullptr;
    }
    //--------------------------------------------------------------------------
    void UString::_base_iterator::_seekFwd( size_type c )
    {
        mIter += c;
    }
    //--------------------------------------------------------------------------
    void UString::_base_iterator::_seekRev( size_type c )
    {
        mIter -= c;
    }
    //--------------------------------------------------------------------------
    void UString::_base_iterator::_become( const _base_iterator& i )
    {
        mIter = i.mIter;
        mString = i.mString;
    }
    //--------------------------------------------------------------------------
    bool UString::_base_iterator::_test_begin() const
    {
        return mIter == mString->mData.begin();
    }
    //--------------------------------------------------------------------------
    bool UString::_base_iterator::_test_end() const
    {
        return mIter == mString->mData.end();
    }
    //--------------------------------------------------------------------------
    UString::size_type UString::_base_iterator::_get_index() const
    {
        return mIter - mString->mData.begin();
    }
    //--------------------------------------------------------------------------
    void UString::_base_iterator::_jump_to( size_type index )
    {
        mIter = mString->mData.begin() + index;
    }
    //--------------------------------------------------------------------------
    UString::unicode_char UString::_base_iterator::_getCharacter() const
    {
        size_type current_index = _get_index();
        return mString->getChar( current_index );
    }
    //--------------------------------------------------------------------------
    int UString::_base_iterator::_setCharacter( unicode_char uc )
    {
        size_type current_index = _get_index();
        int change = mString->setChar( current_index, uc );
        _jump_to( current_index );
        return change;
    }
    //--------------------------------------------------------------------------
    void UString::_base_iterator::_moveNext()
    {
        _seekFwd( 1 ); // move 1 code point forward
        if ( _test_end() ) return; // exit if we hit the end
        if ( _utf16_surrogate_follow( mIter[0] ) ) {
            // landing on a follow code point means we might be part of a bigger character
            // so we test for that
            code_point lead_half = 0;
            //NB: we can't possibly be at the beginning here, so no need to test
            lead_half = mIter[-1]; // check the previous code point to see if we're part of a surrogate pair
            if ( _utf16_surrogate_lead( lead_half ) ) {
                _seekFwd( 1 ); // if so, then advance 1 more code point
            }
        }
    }
    //--------------------------------------------------------------------------
    void UString::_base_iterator::_movePrev()
    {
        _seekRev( 1 ); // move 1 code point backwards
        if ( _test_begin() ) return; // exit if we hit the beginning
        if ( _utf16_surrogate_follow( mIter[0] ) ) {
            // landing on a follow code point means we might be part of a bigger character
            // so we test for that
            code_point lead_half = 0;
            lead_half = mIter[-1]; // check the previous character to see if we're part of a surrogate pair
            if ( _utf16_surrogate_lead( lead_half ) ) {
                _seekRev( 1 ); // if so, then rewind 1 more code point
            }
        }
    }
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    UString::_fwd_iterator::_fwd_iterator() = default;
    //--------------------------------------------------------------------------
    UString::_fwd_iterator::_fwd_iterator( const _fwd_iterator& i )
    {
        _become( i );
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator& UString::_fwd_iterator::operator=( const _fwd_iterator& i )
    {
        _become( i );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator& UString::_fwd_iterator::operator++()
    {
        _seekFwd( 1 );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator UString::_fwd_iterator::operator++( int )
    {
        _fwd_iterator tmp( *this );
        _seekFwd( 1 );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator& UString::_fwd_iterator::operator--()
    {
        _seekRev( 1 );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator UString::_fwd_iterator::operator--( int )
    {
        _fwd_iterator tmp( *this );
        _seekRev( 1 );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator UString::_fwd_iterator::operator+( difference_type n )
    {
        _fwd_iterator tmp( *this );
        if ( n < 0 )
            tmp._seekRev( -n );
        else
            tmp._seekFwd( n );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator UString::_fwd_iterator::operator-( difference_type n )
    {
        _fwd_iterator tmp( *this );
        if ( n < 0 )
            tmp._seekFwd( -n );
        else
            tmp._seekRev( n );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator& UString::_fwd_iterator::operator+=( difference_type n )
    {
        if ( n < 0 )
            _seekRev( -n );
        else
            _seekFwd( n );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator& UString::_fwd_iterator::operator-=( difference_type n )
    {
        if ( n < 0 )
            _seekFwd( -n );
        else
            _seekRev( n );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::value_type& UString::_fwd_iterator::operator*() const
    {
        return *mIter;
    }
    //--------------------------------------------------------------------------
    UString::value_type& UString::_fwd_iterator::operator[]( difference_type n ) const
    {
        _fwd_iterator tmp( *this );
        tmp += n;
        return *tmp;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator& UString::_fwd_iterator::moveNext()
    {
        _moveNext();
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_fwd_iterator& UString::_fwd_iterator::movePrev()
    {
        _movePrev();
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::unicode_char UString::_fwd_iterator::getCharacter() const
    {
        return _getCharacter();
    }
    //--------------------------------------------------------------------------
    int UString::_fwd_iterator::setCharacter( unicode_char uc )
    {
        return _setCharacter( uc );
    }
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator::_const_fwd_iterator() = default;
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator::_const_fwd_iterator( const _const_fwd_iterator& i )
    {
        _become( i );
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator& UString::_const_fwd_iterator::operator=( const _const_fwd_iterator& i )
    {
        _become( i );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator::_const_fwd_iterator( const _fwd_iterator& i )
    {
        _become( i );
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator& UString::_const_fwd_iterator::operator++()
    {
        _seekFwd( 1 );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator UString::_const_fwd_iterator::operator++( int )
    {
        _const_fwd_iterator tmp( *this );
        _seekFwd( 1 );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator& UString::_const_fwd_iterator::operator--()
    {
        _seekRev( 1 );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator UString::_const_fwd_iterator::operator--( int )
    {
        _const_fwd_iterator tmp( *this );
        _seekRev( 1 );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator UString::_const_fwd_iterator::operator+( difference_type n )
    {
        _const_fwd_iterator tmp( *this );
        if ( n < 0 )
            tmp._seekRev( -n );
        else
            tmp._seekFwd( n );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator UString::_const_fwd_iterator::operator-( difference_type n )
    {
        _const_fwd_iterator tmp( *this );
        if ( n < 0 )
            tmp._seekFwd( -n );
        else
            tmp._seekRev( n );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator& UString::_const_fwd_iterator::operator+=( difference_type n )
    {
        if ( n < 0 )
            _seekRev( -n );
        else
            _seekFwd( n );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator& UString::_const_fwd_iterator::operator-=( difference_type n )
    {
        if ( n < 0 )
            _seekFwd( -n );
        else
            _seekRev( n );
        return *this;
    }
    //--------------------------------------------------------------------------
    const UString::value_type& UString::_const_fwd_iterator::operator*() const
    {
        return *mIter;
    }
    //--------------------------------------------------------------------------
    const UString::value_type& UString::_const_fwd_iterator::operator[]( difference_type n ) const
    {
        _const_fwd_iterator tmp( *this );
        tmp += n;
        return *tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator& UString::_const_fwd_iterator::moveNext()
    {
        _moveNext();
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_const_fwd_iterator& UString::_const_fwd_iterator::movePrev()
    {
        _movePrev();
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::unicode_char UString::_const_fwd_iterator::getCharacter() const
    {
        return _getCharacter();
    }
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    UString::_rev_iterator::_rev_iterator() = default;
    //--------------------------------------------------------------------------
    UString::_rev_iterator::_rev_iterator( const _rev_iterator& i )
    {
        _become( i );
    }
    //--------------------------------------------------------------------------
    UString::_rev_iterator& UString::_rev_iterator::operator++()
    {
        _seekRev( 1 );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_rev_iterator UString::_rev_iterator::operator++( int )
    {
        _rev_iterator tmp( *this );
        _seekRev( 1 );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_rev_iterator& UString::_rev_iterator::operator--()
    {
        _seekFwd( 1 );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_rev_iterator UString::_rev_iterator::operator--( int )
    {
        _rev_iterator tmp( *this );
        _seekFwd( 1 );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_rev_iterator UString::_rev_iterator::operator+( difference_type n )
    {
        _rev_iterator tmp( *this );
        if ( n < 0 )
            tmp._seekFwd( -n );
        else
            tmp._seekRev( n );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_rev_iterator UString::_rev_iterator::operator-( difference_type n )
    {
        _rev_iterator tmp( *this );
        if ( n < 0 )
            tmp._seekRev( -n );
        else
            tmp._seekFwd( n );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_rev_iterator& UString::_rev_iterator::operator+=( difference_type n )
    {
        if ( n < 0 )
            _seekFwd( -n );
        else
            _seekRev( n );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_rev_iterator& UString::_rev_iterator::operator-=( difference_type n )
    {
        if ( n < 0 )
            _seekRev( -n );
        else
            _seekFwd( n );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::value_type& UString::_rev_iterator::operator*() const
    {
        return mIter[-1];
    }
    //--------------------------------------------------------------------------
    UString::value_type& UString::_rev_iterator::operator[]( difference_type n ) const
    {
        _rev_iterator tmp( *this );
        tmp -= n;
        return *tmp;
    }
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator::_const_rev_iterator() = default;
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator::_const_rev_iterator( const _const_rev_iterator& i )
    {
        _become( i );
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator::_const_rev_iterator( const _rev_iterator& i )
    {
        _become( i );
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator& UString::_const_rev_iterator::operator++()
    {
        _seekRev( 1 );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator UString::_const_rev_iterator::operator++( int )
    {
        _const_rev_iterator tmp( *this );
        _seekRev( 1 );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator& UString::_const_rev_iterator::operator--()
    {
        _seekFwd( 1 );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator UString::_const_rev_iterator::operator--( int )
    {
        _const_rev_iterator tmp( *this );
        _seekFwd( 1 );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator UString::_const_rev_iterator::operator+( difference_type n )
    {
        _const_rev_iterator tmp( *this );
        if ( n < 0 )
            tmp._seekFwd( -n );
        else
            tmp._seekRev( n );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator UString::_const_rev_iterator::operator-( difference_type n )
    {
        _const_rev_iterator tmp( *this );
        if ( n < 0 )
            tmp._seekRev( -n );
        else
            tmp._seekFwd( n );
        return tmp;
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator& UString::_const_rev_iterator::operator+=( difference_type n )
    {
        if ( n < 0 )
            _seekFwd( -n );
        else
            _seekRev( n );
        return *this;
    }
    //--------------------------------------------------------------------------
    UString::_const_rev_iterator& UString::_const_rev_iterator::operator-=( difference_type n )
    {
        if ( n < 0 )
            _seekRev( -n );
        else
            _seekFwd( n );
        return *this;
    }
    //--------------------------------------------------------------------------
    const UString::value_type& UString::_const_rev_iterator::operator*() const
    {
        return mIter[-1];
    }
    //--------------------------------------------------------------------------
    const UString::value_type& UString::_const_rev_iterator::operator[]( difference_type n ) const
    {
        _const_rev_iterator tmp( *this );
        tmp -= n;
        return *tmp;
    }
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    //--------------------------------------------------------------------------
    UString::UString()
    {
        _init();
    }
    //--------------------------------------------------------------------------
    UString::UString( const UString& copy )
    {
        _init();
        mData = copy.mData;
    }
    //--------------------------------------------------------------------------
    UString::UString( size_type length, const code_point& ch )
    {
        _init();
        assign( length, ch );
    }
    //--------------------------------------------------------------------------
    UString::UString( const code_point* str )
    {
        _init();
        assign( str );
    }
    //--------------------------------------------------------------------------
    UString::UString( const code_point* str, size_type length )
    {
        _init();
        assign( str, length );
    }
    //--------------------------------------------------------------------------
    UString::UString( const UString& str, size_type index, size_type length )
    {
        _init();
        assign( str, index, length );
    }
    //--------------------------------------------------------------------------
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::UString( const wchar_t* w_str )
    {
        _init();
        assign( w_str );
    }
    //--------------------------------------------------------------------------
    UString::UString( const wchar_t* w_str, size_type length )
    {
        _init();
        assign( w_str, length );
    }
#endif
    //--------------------------------------------------------------------------
    UString::UString( const std::wstring& wstr )
    {
        _init();
        assign( wstr );
    }
    //--------------------------------------------------------------------------
    UString::UString( const char* c_str )
    {
        _init();
        assign( c_str );
    }
    //--------------------------------------------------------------------------
    UString::UString( const char* c_str, size_type length )
    {
        _init();
        assign( c_str, length );
    }
    //--------------------------------------------------------------------------
    UString::UString( const std::string& str )
    {
        _init();
        assign( str );
    }
    //--------------------------------------------------------------------------
    UString::UString( const utf32string & str )
    {
        _init();
        assign( str );
    }
    //--------------------------------------------------------------------------
    UString::~UString()
    {
        _cleanBuffer();
    }
    //--------------------------------------------------------------------------
    UString::size_type UString::size() const
    {
        return mData.size();
    }
    //--------------------------------------------------------------------------
    UString::size_type UString::length() const
    {
        return size();
    }
    //--------------------------------------------------------------------------
    UString::size_type UString::length_Characters() const
    {
        const_iterator i = begin(), ie = end();
        size_type c = 0;
        while ( i != ie ) {
            i.moveNext();
            ++c;
        }
        return c;
    }
    //--------------------------------------------------------------------------
    UString::size_type UString::max_size() const
    {
        return mData.max_size();
    }
    //--------------------------------------------------------------------------
    void UString::reserve( size_type size )
    {
        mData.reserve( size );
    }
    //--------------------------------------------------------------------------
    void UString::resize( size_type num, const code_point& val /*= 0 */ )
    {
        mData.resize( num, val );
    }
    //--------------------------------------------------------------------------
    void UString::swap( UString& from )
    {
        mData.swap( from.mData );
    }
    //--------------------------------------------------------------------------
    bool UString::empty() const
    {
        return mData.empty();
    }
    //--------------------------------------------------------------------------
    const UString::code_point* UString::c_str() const
    {
        return mData.c_str();
    }
    //--------------------------------------------------------------------------
    const UString::code_point* UString::data() const
    {
        return c_str();
    }
    //--------------------------------------------------------------------------
    UString::size_type UString::capacity() const
    {
        return mData.capacity();
    }
    //--------------------------------------------------------------------------
    void UString::clear()
    {
        mData.clear();
    }
    //--------------------------------------------------------------------------
    UString UString::substr( size_type index, size_type num /*= npos */ ) const
    {
        // this could avoid the extra copy if we used a private specialty constructor
        dstring data = mData.substr( index, num );
        UString tmp;
        tmp.mData.swap( data );
        return tmp;
    }
    //--------------------------------------------------------------------------
    void UString::push_back( unicode_char val )
    {
        code_point cp[2];
        size_t c = _utf32_to_utf16( val, cp );
        if ( c > 0 ) push_back( cp[0] );
        if ( c > 1 ) push_back( cp[1] );
    }
    //--------------------------------------------------------------------------
#if MYGUI_IS_NATIVE_WCHAR_T
    void UString::push_back( wchar_t val )
    {
        // we do this because the Unicode method still preserves UTF-16 code points
        mData.push_back( static_cast<code_point>( val ) );
    }
#endif
    //--------------------------------------------------------------------------
    void UString::push_back( code_point val )
    {
        mData.push_back( val );
    }
 
    void UString::push_back( char val )
    {
        mData.push_back( static_cast<code_point>( val ) );
    }
 
    bool UString::inString( unicode_char ch ) const
    {
        const_iterator i, ie = end();
        for ( i = begin(); i != ie; i.moveNext() ) {
            if ( i.getCharacter() == ch )
                return true;
        }
        return false;
    }
 
    const std::string& UString::asUTF8() const
    {
        _load_buffer_UTF8();
        return *m_buffer.mStrBuffer;
    }
 
    const char* UString::asUTF8_c_str() const
    {
        _load_buffer_UTF8();
        return m_buffer.mStrBuffer->c_str();
    }
 
    const UString::utf32string& UString::asUTF32() const
    {
        _load_buffer_UTF32();
        return *m_buffer.mUTF32StrBuffer;
    }
 
    const UString::unicode_char* UString::asUTF32_c_str() const
    {
        _load_buffer_UTF32();
        return m_buffer.mUTF32StrBuffer->c_str();
    }
 
    const std::wstring& UString::asWStr() const
    {
        _load_buffer_WStr();
        return *m_buffer.mWStrBuffer;
    }
 
    const wchar_t* UString::asWStr_c_str() const
    {
        _load_buffer_WStr();
        return m_buffer.mWStrBuffer->c_str();
    }
 
    UString::code_point& UString::at( size_type loc )
    {
        return mData.at( loc );
    }
 
    const UString::code_point& UString::at( size_type loc ) const
    {
        return mData.at( loc );
    }
 
    UString::unicode_char UString::getChar( size_type loc ) const
    {
        const code_point* ptr = c_str();
        unicode_char uc;
        size_t l = _utf16_char_length( ptr[loc] );
        code_point cp[2] = { /* blame the code beautifier */
            0, 0
        };
        cp[0] = ptr[loc];
 
        if ( l == 2 && ( loc + 1 ) < mData.length() ) {
            cp[1] = ptr[loc+1];
        }
        _utf16_to_utf32( cp, uc );
        return uc;
    }
 
    int UString::setChar( size_type loc, unicode_char ch )
    {
        code_point cp[2] = { /* blame the code beautifier */
            0, 0
        };
        size_t l = _utf32_to_utf16( ch, cp );
        unicode_char existingChar = getChar( loc );
        size_t existingSize = _utf16_char_length( existingChar );
        size_t newSize = _utf16_char_length( ch );
 
        if ( newSize > existingSize ) {
            at( loc ) = cp[0];
            insert( loc + 1, 1, cp[1] );
            return 1;
        }
        if ( newSize < existingSize ) {
            erase( loc, 1 );
            at( loc ) = cp[0];
            return -1;
        }
 
        // newSize == existingSize
        at( loc ) = cp[0];
        if ( l == 2 ) at( loc + 1 ) = cp[1];
        return 0;
    }
 
    UString::iterator UString::begin()
    {
        iterator i;
        i.mIter = mData.begin();
        i.mString = this;
        return i;
    }
 
    UString::const_iterator UString::begin() const
    {
        const_iterator i;
        i.mIter = const_cast<UString*>( this )->mData.begin();
        i.mString = const_cast<UString*>( this );
        return i;
    }
 
    UString::iterator UString::end()
    {
        iterator i;
        i.mIter = mData.end();
        i.mString = this;
        return i;
    }
 
    UString::const_iterator UString::end() const
    {
        const_iterator i;
        i.mIter = const_cast<UString*>( this )->mData.end();
        i.mString = const_cast<UString*>( this );
        return i;
    }
 
    UString::reverse_iterator UString::rbegin()
    {
        reverse_iterator i;
        i.mIter = mData.end();
        i.mString = this;
        return i;
    }
 
    UString::const_reverse_iterator UString::rbegin() const
    {
        const_reverse_iterator i;
        i.mIter = const_cast<UString*>( this )->mData.end();
        i.mString = const_cast<UString*>( this );
        return i;
    }
 
    UString::reverse_iterator UString::rend()
    {
        reverse_iterator i;
        i.mIter = mData.begin();
        i.mString = this;
        return i;
    }
 
    UString::const_reverse_iterator UString::rend() const
    {
        const_reverse_iterator i;
        i.mIter = const_cast<UString*>( this )->mData.begin();
        i.mString = const_cast<UString*>( this );
        return i;
    }
 
    UString& UString::assign( iterator start, iterator end )
    {
        mData.assign( start.mIter, end.mIter );
        return *this;
    }
 
    UString& UString::assign( const UString& str )
    {
        mData.assign( str.mData );
        return *this;
    }
 
    UString& UString::assign( const code_point* str )
    {
        mData.assign( str );
        return *this;
    }
 
    UString& UString::assign( const code_point* str, size_type num )
    {
        mData.assign( str, num );
        return *this;
    }
 
    UString& UString::assign( const UString& str, size_type index, size_type len )
    {
        mData.assign( str.mData, index, len );
        return *this;
    }
 
    UString& UString::assign( size_type num, const code_point& ch )
    {
        mData.assign( num, ch );
        return *this;
    }
 
    UString& UString::assign( const std::wstring& wstr )
    {
        mData.clear();
        mData.reserve( wstr.length() ); // best guess bulk allocate
#ifdef WCHAR_UTF16 // if we're already working in UTF-16, this is easy
        code_point tmp;
        std::wstring::const_iterator i, ie = wstr.end();
        for ( i = wstr.begin(); i != ie; i++ ) {
            tmp = static_cast<code_point>( *i );
            mData.push_back( tmp );
        }
#else // otherwise we do it the safe way (which is still 100% safe to pass UTF-16 through, just slower)
        code_point cp[3] = {0, 0, 0};
        unicode_char tmp;
        std::wstring::const_iterator i, ie = wstr.end();
        for ( i = wstr.begin(); i != ie; i++ ) {
            tmp = static_cast<unicode_char>( *i );
            size_t l = _utf32_to_utf16( tmp, cp );
            if ( l > 0 ) mData.push_back( cp[0] );
            if ( l > 1 ) mData.push_back( cp[1] );
        }
#endif
        return *this;
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString& UString::assign( const wchar_t* w_str )
    {
        std::wstring tmp;
        tmp.assign( w_str );
        return assign( tmp );
    }
 
    UString& UString::assign( const wchar_t* w_str, size_type num )
    {
        std::wstring tmp;
        tmp.assign( w_str, num );
        return assign( tmp );
    }
#endif
 
    UString& UString::assign( const std::string& str )
    {
        size_type len = _verifyUTF8( str );
        clear(); // empty our contents, if there are any
        reserve( len ); // best guess bulk capacity growth
 
        // This is a 3 step process, converting each byte in the UTF-8 stream to UTF-32,
        // then converting it to UTF-16, then finally appending the data buffer
 
        unicode_char uc;          // temporary Unicode character buffer
        unsigned char utf8buf[7]; // temporary UTF-8 buffer
        utf8buf[6] = 0;
        size_t utf8len;           // UTF-8 length
        code_point utf16buff[3];  // temporary UTF-16 buffer
        utf16buff[2] = 0;
        size_t utf16len;          // UTF-16 length
 
        std::string::const_iterator i, ie = str.end();
        for ( i = str.begin(); i != ie; i++ ) {
            utf8len = _utf8_char_length( static_cast<unsigned char>( *i ) ); // estimate bytes to load
            for ( size_t j = 0; j < utf8len; j++ ) { // load the needed UTF-8 bytes
                utf8buf[j] = ( static_cast<unsigned char>( *( i + j ) ) ); // we don't increment 'i' here just in case the estimate is wrong (shouldn't happen, but we're being careful)
            }
            utf8buf[utf8len] = 0; // nul terminate so we throw an exception before running off the end of the buffer
            utf8len = _utf8_to_utf32( utf8buf, uc ); // do the UTF-8 -> UTF-32 conversion
            i += utf8len - 1; // we subtract 1 for the increment of the 'for' loop
 
            utf16len = _utf32_to_utf16( uc, utf16buff ); // UTF-32 -> UTF-16 conversion
            append( utf16buff, utf16len ); // append the characters to the string
        }
        return *this;
    }
 
    UString& UString::assign( const utf32string& str )
    {
        for (const auto& character : str)
        {
            push_back(character);
        }
        return *this;
    }
 
    UString& UString::assign( const char* c_str )
    {
        std::string tmp( c_str );
        return assign( tmp );
    }
 
    UString& UString::assign( const char* c_str, size_type num )
    {
        std::string tmp;
        tmp.assign( c_str, num );
        return assign( tmp );
    }
 
    UString& UString::append( const UString& str )
    {
        mData.append( str.mData );
        return *this;
    }
 
    UString& UString::append( const code_point* str )
    {
        mData.append( str );
        return *this;
    }
 
    UString& UString::append( const UString& str, size_type index, size_type len )
    {
        mData.append( str.mData, index, len );
        return *this;
    }
 
    UString& UString::append( const code_point* str, size_type num )
    {
        mData.append( str, num );
        return *this;
    }
 
    UString& UString::append( size_type num, code_point ch )
    {
        mData.append( num, ch );
        return *this;
    }
 
    UString& UString::append( iterator start, iterator end )
    {
        mData.append( start.mIter, end.mIter );
        return *this;
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString& UString::append( const wchar_t* w_str, size_type num )
    {
        std::wstring tmp( w_str, num );
        return append( tmp );
    }
 
    UString& UString::append( size_type num, wchar_t ch )
    {
        return append( num, static_cast<unicode_char>( ch ) );
    }
#endif
    UString& UString::append( const char* c_str, size_type num )
    {
        UString tmp( c_str, num );
        append( tmp );
        return *this;
    }
 
    UString& UString::append( size_type num, char ch )
    {
        append( num, static_cast<code_point>( ch ) );
        return *this;
    }
 
    UString& UString::append( size_type num, unicode_char ch )
    {
        code_point cp[2] = {0, 0};
        if ( _utf32_to_utf16( ch, cp ) == 2 ) {
            for ( size_type i = 0; i < num; i++ ) {
                append( 1, cp[0] );
                append( 1, cp[1] );
            }
        } else {
            for ( size_type i = 0; i < num; i++ ) {
                append( 1, cp[0] );
            }
        }
        return *this;
    }
 
    UString::iterator UString::insert( iterator i, const code_point& ch )
    {
        iterator ret;
        ret.mIter = mData.insert( i.mIter, ch );
        ret.mString = this;
        return ret;
    }
 
    UString& UString::insert( size_type index, const UString& str )
    {
        mData.insert( index, str.mData );
        return *this;
    }
 
    UString& UString::insert( size_type index1, const UString& str, size_type index2, size_type num )
    {
        mData.insert( index1, str.mData, index2, num );
        return *this;
    }
 
    void UString::insert( iterator i, iterator start, iterator end )
    {
        mData.insert( i.mIter, start.mIter, end.mIter );
    }
 
    UString& UString::insert( size_type index, const code_point* str, size_type num )
    {
        mData.insert( index, str, num );
        return *this;
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString& UString::insert( size_type index, const wchar_t* w_str, size_type num )
    {
        UString tmp( w_str, num );
        insert( index, tmp );
        return *this;
    }
#endif
 
    UString& UString::insert( size_type index, const char* c_str, size_type num )
    {
        UString tmp( c_str, num );
        insert( index, tmp );
        return *this;
    }
 
    UString& UString::insert( size_type index, size_type num, code_point ch )
    {
        mData.insert( index, num, ch );
        return *this;
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString& UString::insert( size_type index, size_type num, wchar_t ch )
    {
        insert( index, num, static_cast<unicode_char>( ch ) );
        return *this;
    }
#endif
 
    UString& UString::insert( size_type index, size_type num, char ch )
    {
        insert( index, num, static_cast<code_point>( ch ) );
        return *this;
    }
 
    UString& UString::insert( size_type index, size_type num, unicode_char ch )
    {
        code_point cp[3] = {0, 0, 0};
        size_t l = _utf32_to_utf16( ch, cp );
        if ( l == 1 ) {
            return insert( index, num, cp[0] );
        }
        for ( size_type c = 0; c < num; c++ ) {
            // insert in reverse order to preserve ordering after insert
            insert( index, 1, cp[1] );
            insert( index, 1, cp[0] );
        }
        return *this;
    }
 
    void UString::insert( iterator i, size_type num, const code_point& ch )
    {
        mData.insert( i.mIter, num, ch );
    }
#if MYGUI_IS_NATIVE_WCHAR_T
    void UString::insert( iterator i, size_type num, const wchar_t& ch )
    {
        insert( i, num, static_cast<unicode_char>( ch ) );
    }
#endif
 
    void UString::insert( iterator i, size_type num, const char& ch )
    {
        insert( i, num, static_cast<code_point>( ch ) );
    }
 
    void UString::insert( iterator i, size_type num, const unicode_char& ch )
    {
        code_point cp[3] = {0, 0, 0};
        size_t l = _utf32_to_utf16( ch, cp );
        if ( l == 1 ) {
            insert( i, num, cp[0] );
        } else {
            for ( size_type c = 0; c < num; c++ ) {
                // insert in reverse order to preserve ordering after insert
                insert( i, 1, cp[1] );
                insert( i, 1, cp[0] );
            }
        }
    }
 
    UString::iterator UString::erase( iterator loc )
    {
        iterator ret;
        ret.mIter = mData.erase( loc.mIter );
        ret.mString = this;
        return ret;
    }
 
    UString::iterator UString::erase( iterator start, iterator end )
    {
        iterator ret;
        ret.mIter = mData.erase( start.mIter, end.mIter );
        ret.mString = this;
        return ret;
    }
 
    UString& UString::erase( size_type index /*= 0*/, size_type num /*= npos */ )
    {
        if ( num == npos )
            mData.erase( index );
        else
            mData.erase( index, num );
        return *this;
    }
 
    UString& UString::replace( size_type index1, size_type num1, const UString& str )
    {
        mData.replace( index1, num1, str.mData, 0, npos );
        return *this;
    }
 
    UString& UString::replace( size_type index1, size_type num1, const UString& str, size_type num2 )
    {
        mData.replace( index1, num1, str.mData, 0, num2 );
        return *this;
    }
 
    UString& UString::replace( size_type index1, size_type num1, const UString& str, size_type index2, size_type num2 )
    {
        mData.replace( index1, num1, str.mData, index2, num2 );
        return *this;
    }
 
    UString& UString::replace( iterator start, iterator end, const UString& str, size_type num /*= npos */ )
    {
        _const_fwd_iterator st(start); //Work around for gcc, allow it to find correct overload
 
        size_type index1 = begin() - st;
        size_type num1 = end - st;
        return replace( index1, num1, str, 0, num );
    }
 
    UString& UString::replace( size_type index, size_type num1, size_type num2, code_point ch )
    {
        mData.replace( index, num1, num2, ch );
        return *this;
    }
 
    UString& UString::replace( iterator start, iterator end, size_type num, code_point ch )
    {
        _const_fwd_iterator st(start); //Work around for gcc, allow it to find correct overload
 
        size_type index1 = begin() - st;
        size_type num1 = end - st;
        return replace( index1, num1, num, ch );
    }
 
    int UString::compare( const UString& str ) const
    {
        return mData.compare( str.mData );
    }
 
    int UString::compare( const code_point* str ) const
    {
        return mData.compare( str );
    }
 
    int UString::compare( size_type index, size_type length, const UString& str ) const
    {
        return mData.compare( index, length, str.mData );
    }
 
    int UString::compare( size_type index, size_type length, const UString& str, size_type index2, size_type length2 ) const
    {
        return mData.compare( index, length, str.mData, index2, length2 );
    }
 
    int UString::compare( size_type index, size_type length, const code_point* str, size_type length2 ) const
    {
        return mData.compare( index, length, str, length2 );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    int UString::compare( size_type index, size_type length, const wchar_t* w_str, size_type length2 ) const
    {
        UString tmp( w_str, length2 );
        return compare( index, length, tmp );
    }
#endif
 
    int UString::compare( size_type index, size_type length, const char* c_str, size_type length2 ) const
    {
        UString tmp( c_str, length2 );
        return compare( index, length, tmp );
    }
 
    UString::size_type UString::find( const UString& str, size_type index /*= 0 */ ) const
    {
        return mData.find( str.c_str(), index );
    }
 
    UString::size_type UString::find( const code_point* cp_str, size_type index, size_type length ) const
    {
        UString tmp( cp_str );
        return mData.find( tmp.c_str(), index, length );
    }
 
    UString::size_type UString::find( const char* c_str, size_type index, size_type length ) const
    {
        UString tmp( c_str );
        return mData.find( tmp.c_str(), index, length );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::size_type UString::find( const wchar_t* w_str, size_type index, size_type length ) const
    {
        UString tmp( w_str );
        return mData.find( tmp.c_str(), index, length );
    }
#endif
 
    UString::size_type UString::find( char ch, size_type index /*= 0 */ ) const
    {
        return find( static_cast<code_point>( ch ), index );
    }
 
    UString::size_type UString::find( code_point ch, size_type index /*= 0 */ ) const
    {
        return mData.find( ch, index );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::size_type UString::find( wchar_t ch, size_type index /*= 0 */ ) const
    {
        return find( static_cast<unicode_char>( ch ), index );
    }
#endif
 
    UString::size_type UString::find( unicode_char ch, size_type index /*= 0 */ ) const
    {
        code_point cp[3] = {0, 0, 0};
        size_t l = _utf32_to_utf16( ch, cp );
        return find( UString( cp, l ), index );
    }
 
    UString::size_type UString::rfind( const UString& str, size_type index /*= 0 */ ) const
    {
        return mData.rfind( str.c_str(), index );
    }
 
    UString::size_type UString::rfind( const code_point* cp_str, size_type index, size_type num ) const
    {
        UString tmp( cp_str );
        return mData.rfind( tmp.c_str(), index, num );
    }
 
    UString::size_type UString::rfind( const char* c_str, size_type index, size_type num ) const
    {
        UString tmp( c_str );
        return mData.rfind( tmp.c_str(), index, num );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::size_type UString::rfind( const wchar_t* w_str, size_type index, size_type num ) const
    {
        UString tmp( w_str );
        return mData.rfind( tmp.c_str(), index, num );
    }
#endif
 
    UString::size_type UString::rfind( char ch, size_type index /*= 0 */ ) const
    {
        return rfind( static_cast<code_point>( ch ), index );
    }
 
    UString::size_type UString::rfind( code_point ch, size_type index ) const
    {
        return mData.rfind( ch, index );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::size_type UString::rfind( wchar_t ch, size_type index /*= 0 */ ) const
    {
        return rfind( static_cast<unicode_char>( ch ), index );
    }
#endif
 
    UString::size_type UString::rfind( unicode_char ch, size_type index /*= 0 */ ) const
    {
        code_point cp[3] = {0, 0, 0};
        size_t l = _utf32_to_utf16( ch, cp );
        return rfind( UString( cp, l ), index );
    }
 
    UString::size_type UString::find_first_of( const UString &str, size_type index /*= 0*/, size_type num /*= npos */ ) const
    {
        size_type i = 0;
        const size_type len = length();
        while ( i < num && ( index + i ) < len ) {
            unicode_char ch = getChar( index + i );
            if ( str.inString( ch ) )
                return index + i;
            i += _utf16_char_length( ch ); // increment by the Unicode character length
        }
        return npos;
    }
 
    UString::size_type UString::find_first_of( code_point ch, size_type index /*= 0 */ ) const
    {
        UString tmp;
        tmp.assign( 1, ch );
        return find_first_of( tmp, index );
    }
 
    UString::size_type UString::find_first_of( char ch, size_type index /*= 0 */ ) const
    {
        return find_first_of( static_cast<code_point>( ch ), index );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::size_type UString::find_first_of( wchar_t ch, size_type index /*= 0 */ ) const
    {
        return find_first_of( static_cast<unicode_char>( ch ), index );
    }
#endif
 
    UString::size_type UString::find_first_of( unicode_char ch, size_type index /*= 0 */ ) const
    {
        code_point cp[3] = {0, 0, 0};
        size_t l = _utf32_to_utf16( ch, cp );
        return find_first_of( UString( cp, l ), index );
    }
 
    UString::size_type UString::find_first_not_of( const UString& str, size_type index /*= 0*/, size_type num /*= npos */ ) const
    {
        size_type i = 0;
        const size_type len = length();
        while ( i < num && ( index + i ) < len ) {
            unicode_char ch = getChar( index + i );
            if ( !str.inString( ch ) )
                return index + i;
            i += _utf16_char_length( ch ); // increment by the Unicode character length
        }
        return npos;
    }
 
    UString::size_type UString::find_first_not_of( code_point ch, size_type index /*= 0 */ ) const
    {
        UString tmp;
        tmp.assign( 1, ch );
        return find_first_not_of( tmp, index );
    }
 
    UString::size_type UString::find_first_not_of( char ch, size_type index /*= 0 */ ) const
    {
        return find_first_not_of( static_cast<code_point>( ch ), index );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::size_type UString::find_first_not_of( wchar_t ch, size_type index /*= 0 */ ) const
    {
        return find_first_not_of( static_cast<unicode_char>( ch ), index );
    }
#endif
 
    UString::size_type UString::find_first_not_of( unicode_char ch, size_type index /*= 0 */ ) const
    {
        code_point cp[3] = {0, 0, 0};
        size_t l = _utf32_to_utf16( ch, cp );
        return find_first_not_of( UString( cp, l ), index );
    }
 
    UString::size_type UString::find_last_of( const UString& str, size_type index /*= npos*/, size_type num /*= npos */ ) const
    {
        size_type i = 0;
        const size_type len = length();
        if ( index > len ) index = len - 1;
 
        while ( i < num && ( index - i ) != npos ) {
            size_type j = index - i;
            // careful to step full Unicode characters
            if ( j != 0 && _utf16_surrogate_follow( at( j ) ) && _utf16_surrogate_lead( at( j - 1 ) ) ) {
                j = index - ++i;
            }
            // and back to the usual dull test
            unicode_char ch = getChar( j );
            if ( str.inString( ch ) )
                return j;
            i++;
        }
        return npos;
    }
 
    UString::size_type UString::find_last_of( code_point ch, size_type index /*= npos */ ) const
    {
        UString tmp;
        tmp.assign( 1, ch );
        return find_last_of( tmp, index );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::size_type UString::find_last_of( wchar_t ch, size_type index /*= npos */ ) const
    {
        return find_last_of( static_cast<unicode_char>( ch ), index );
    }
#endif
 
    UString::size_type UString::find_last_of( unicode_char ch, size_type index /*= npos */ ) const
    {
        code_point cp[3] = {0, 0, 0};
        size_t l = _utf32_to_utf16( ch, cp );
        return find_last_of( UString( cp, l ), index );
    }
 
    UString::size_type UString::find_last_not_of( const UString& str, size_type index /*= npos*/, size_type num /*= npos */ ) const
    {
        size_type i = 0;
        const size_type len = length();
        if ( index > len ) index = len - 1;
 
        while ( i < num && ( index - i ) != npos ) {
            size_type j = index - i;
            // careful to step full Unicode characters
            if ( j != 0 && _utf16_surrogate_follow( at( j ) ) && _utf16_surrogate_lead( at( j - 1 ) ) ) {
                j = index - ++i;
            }
            // and back to the usual dull test
            unicode_char ch = getChar( j );
            if ( !str.inString( ch ) )
                return j;
            i++;
        }
        return npos;
    }
 
    UString::size_type UString::find_last_not_of( code_point ch, size_type index /*= npos */ ) const
    {
        UString tmp;
        tmp.assign( 1, ch );
        return find_last_not_of( tmp, index );
    }
 
    UString::size_type UString::find_last_not_of( char ch, size_type index /*= npos */ ) const
    {
        return find_last_not_of( static_cast<code_point>( ch ), index );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString::size_type UString::find_last_not_of( wchar_t ch, size_type index /*= npos */ ) const
    {
        return find_last_not_of( static_cast<unicode_char>( ch ), index );
    }
#endif
 
    UString::size_type UString::find_last_not_of( unicode_char ch, size_type index /*= npos */ ) const
    {
        code_point cp[3] = {0, 0, 0};
        size_t l = _utf32_to_utf16( ch, cp );
        return find_last_not_of( UString( cp, l ), index );
    }
 
    bool UString::operator<( const UString& right ) const
    {
        return compare( right ) < 0;
    }
 
    bool UString::operator<=( const UString& right ) const
    {
        return compare( right ) <= 0;
    }
 
    UString& UString::operator=( const UString& s )
    {
        return assign( s );
    }
 
    UString& UString::operator=( code_point ch )
    {
        clear();
        return append( 1, ch );
    }
 
    UString& UString::operator=( char ch )
    {
        clear();
        return append( 1, ch );
    }
 
#if MYGUI_IS_NATIVE_WCHAR_T
    UString& UString::operator=( wchar_t ch )
    {
        clear();
        return append( 1, ch );
    }
#endif
 
    UString& UString::operator=( unicode_char ch )
    {
        clear();
        return append( 1, ch );
    }
 
    bool UString::operator>( const UString& right ) const
    {
        return compare( right ) > 0;
    }
 
    bool UString::operator>=( const UString& right ) const
    {
        return compare( right ) >= 0;
    }
 
    bool UString::operator==( const UString& right ) const
    {
        return compare( right ) == 0;
    }
 
    bool UString::operator!=( const UString& right ) const
    {
        return !operator==( right );
    }
 
    UString::code_point& UString::operator[]( size_type index )
    {
        return at( index );
    }
 
    const UString::code_point& UString::operator[]( size_type index ) const
    {
        return at( index );
    }
 
    UString::operator std::string() const 
    {
        return std::string( asUTF8() );
    }
    
    UString::operator std::wstring() const 
    {
        return std::wstring( asWStr() );
    }
 
 
    bool UString::_utf16_independent_char( code_point cp )
    {
        if ( 0xD800 <= cp && cp <= 0xDFFF ) // tests if the cp is within the surrogate pair range
            return false; // it matches a surrogate pair signature
        return true; // everything else is a standalone code point
    }
 
    bool UString::_utf16_surrogate_lead( code_point cp )
    {
        if ( 0xD800 <= cp && cp <= 0xDBFF ) // tests if the cp is within the 2nd word of a surrogate pair
            return true; // it is a 1st word
        return false; // it isn't
    }
 
    bool UString::_utf16_surrogate_follow( code_point cp )
    {
        if ( 0xDC00 <= cp && cp <= 0xDFFF ) // tests if the cp is within the 2nd word of a surrogate pair
            return true; // it is a 2nd word
        return false; // everything else isn't
    }
 
    size_t UString::_utf16_char_length( code_point cp )
    {
        if ( 0xD800 <= cp && cp <= 0xDBFF ) // test if cp is the beginning of a surrogate pair
            return 2; // if it is, then we are 2 words long
        return 1; // otherwise we are only 1 word long
    }
 
    size_t UString::_utf16_char_length( unicode_char uc )
    {
        if ( uc > 0xFFFF ) // test if uc is greater than the single word maximum
            return 2; // if so, we need a surrogate pair
        return 1; // otherwise we can stuff it into a single word
    }
 
    size_t UString::_utf16_to_utf32( const code_point in_cp[2], unicode_char& out_uc )
    {
        const code_point& cp1 = in_cp[0];
        const code_point& cp2 = in_cp[1];
        bool wordPair = false;
 
        // does it look like a surrogate pair?
        if ( 0xD800 <= cp1 && cp1 <= 0xDBFF ) {
            // looks like one, but does the other half match the algorithm as well?
            if ( 0xDC00 <= cp2 && cp2 <= 0xDFFF )
                wordPair = true; // yep!
        }
 
        if ( !wordPair ) { // if we aren't a 100% authentic surrogate pair, then just copy the value
            out_uc = cp1;
            return 1;
        }
 
        unsigned short cU = cp1, cL = cp2; // copy upper and lower words of surrogate pair to writable buffers
        cU -= 0xD800; // remove the encoding markers
        cL -= 0xDC00;
 
        out_uc = ( cU & 0x03FF ) << 10; // grab the 10 upper bits and set them in their proper location
        out_uc |= ( cL & 0x03FF ); // combine in the lower 10 bits
        out_uc += 0x10000; // add back in the value offset
 
        return 2; // this whole operation takes to words, so that's what we'll return
    }
 
    size_t UString::_utf32_to_utf16( const unicode_char& in_uc, code_point out_cp[2] )
    {
        if ( in_uc <= 0xFFFF ) { // we blindly preserve sentinel values because our decoder understands them
            out_cp[0] = static_cast<code_point>(in_uc);
            return 1;
        }
        unicode_char uc = in_uc; // copy to writable buffer
        unsigned short tmp; // single code point buffer
        uc -= 0x10000; // subtract value offset
 
        //process upper word
        tmp = static_cast<unsigned short>(( uc >> 10 ) & 0x03FF); // grab the upper 10 bits
        tmp += 0xD800; // add encoding offset
        out_cp[0] = tmp; // write
 
        // process lower word
        tmp = static_cast<unsigned short>(uc & 0x03FF); // grab the lower 10 bits
        tmp += 0xDC00; // add encoding offset
        out_cp[1] = tmp; // write
 
        return 2; // return used word count (2 for surrogate pairs)
    }
 
    bool UString::_utf8_start_char( unsigned char cp )
    {
        return ( cp & ~_cont_mask ) != _cont;
    }
 
    size_t UString::_utf8_char_length( unsigned char cp )
    {
        if ( !( cp & 0x80 ) ) return 1;
        if (( cp & ~_lead1_mask ) == _lead1 ) return 2;
        if (( cp & ~_lead2_mask ) == _lead2 ) return 3;
        if (( cp & ~_lead3_mask ) == _lead3 ) return 4;
        if (( cp & ~_lead4_mask ) == _lead4 ) return 5;
        if (( cp & ~_lead5_mask ) == _lead5 ) return 6;
 
        return 1;
        //throw invalid_data( "invalid UTF-8 sequence header value" );
    }
 
    size_t UString::_utf8_char_length( unicode_char uc )
    {
        /*
        7 bit:  U-00000000 - U-0000007F: 0xxxxxxx
        11 bit: U-00000080 - U-000007FF: 110xxxxx 10xxxxxx
        16 bit: U-00000800 - U-0000FFFF: 1110xxxx 10xxxxxx 10xxxxxx
        21 bit: U-00010000 - U-001FFFFF: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
        26 bit: U-00200000 - U-03FFFFFF: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
        31 bit: U-04000000 - U-7FFFFFFF: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
        */
        if ( !( uc & ~0x0000007F ) ) return 1;
        if ( !( uc & ~0x000007FF ) ) return 2;
        if ( !( uc & ~0x0000FFFF ) ) return 3;
        if ( !( uc & ~0x001FFFFF ) ) return 4;
        if ( !( uc & ~0x03FFFFFF ) ) return 5;
        if ( !( uc & ~0x7FFFFFFF ) ) return 6;
 
        return 1;
        //throw invalid_data( "invalid UTF-32 value" );
    }
 
    size_t UString::_utf8_to_utf32( const unsigned char in_cp[6], unicode_char& out_uc )
    {
        size_t len = _utf8_char_length( in_cp[0] );
        if ( len == 1 ) { // if we are only 1 byte long, then just grab it and exit
            out_uc = in_cp[0];
            return 1;
        }
 
        unicode_char c = 0; // temporary buffer
        size_t i = 0;
        switch ( len ) { // load header byte
            case 6:
                c = in_cp[i] & _lead5_mask;
                break;
            case 5:
                c = in_cp[i] & _lead4_mask;
                break;
            case 4:
                c = in_cp[i] & _lead3_mask;
                break;
            case 3:
                c = in_cp[i] & _lead2_mask;
                break;
            case 2:
                c = in_cp[i] & _lead1_mask;
                break;
        }
 
        // load each continuation byte
        for ( ++i; i < len; i++ )
        {
            if (( in_cp[i] & ~_cont_mask ) != _cont )
            {
                //throw invalid_data( "bad UTF-8 continuation byte" );
                out_uc = in_cp[0];
                return 1;
            }
            c <<= 6;
            c |= ( in_cp[i] & _cont_mask );
        }
 
        out_uc = c; // write the final value and return the used byte length
        return len;
    }
 
    size_t UString::_utf32_to_utf8( const unicode_char& in_uc, unsigned char out_cp[6] )
    {
        size_t len = _utf8_char_length( in_uc ); // predict byte length of sequence
        unicode_char c = in_uc; // copy to temp buffer
 
        //stuff all of the lower bits
        for ( size_t i = len - 1; i > 0; i-- ) {
            out_cp[i] = static_cast<unsigned char>((( c ) & _cont_mask ) | _cont);
            c >>= 6;
        }
 
        //now write the header byte
        switch ( len ) {
            case 6:
                out_cp[0] = static_cast<unsigned char>((( c ) & _lead5_mask ) | _lead5);
                break;
            case 5:
                out_cp[0] = static_cast<unsigned char>((( c ) & _lead4_mask ) | _lead4);
                break;
            case 4:
                out_cp[0] = static_cast<unsigned char>((( c ) & _lead3_mask ) | _lead3);
                break;
            case 3:
                out_cp[0] = static_cast<unsigned char>((( c ) & _lead2_mask ) | _lead2);
                break;
            case 2:
                out_cp[0] = static_cast<unsigned char>((( c ) & _lead1_mask ) | _lead1);
                break;
            case 1:
            default:
                out_cp[0] = static_cast<unsigned char>(( c ) & 0x7F);
                break;
        }
 
        // return the byte length of the sequence
        return len;
    }
 
    UString::size_type UString::_verifyUTF8( const unsigned char* c_str )
    {
        std::string tmp( reinterpret_cast<const char*>( c_str ) );
        return _verifyUTF8( tmp );
    }
 
    UString::size_type UString::_verifyUTF8( const std::string& str )
    {
        std::string::const_iterator i, ie = str.end();
        i = str.begin();
        size_type length = 0;
 
        while ( i != ie ) {
            // characters pass until we find an extended sequence
            if (( *i ) & 0x80 ) {
                unsigned char c = ( *i );
                size_t contBytes = 0;
 
                // get continuation byte count and test for overlong sequences
                if (( c & ~_lead1_mask ) == _lead1 ) { // 1 additional byte
                    if ( c == _lead1 )
                    {
                        //throw invalid_data( "overlong UTF-8 sequence" );
                        return str.size();
                    }
                    contBytes = 1;
 
                } else if (( c & ~_lead2_mask ) == _lead2 ) { // 2 additional bytes
                    contBytes = 2;
                    if ( c == _lead2 ) { // possible overlong UTF-8 sequence
                        c = ( *( i + 1 ) ); // look ahead to next byte in sequence
                        if (( c & _lead2 ) == _cont )
                        {
                            //throw invalid_data( "overlong UTF-8 sequence" );
                            return str.size();
                        }
                    }
 
                } else if (( c & ~_lead3_mask ) == _lead3 ) { // 3 additional bytes
                    contBytes = 3;
                    if ( c == _lead3 ) { // possible overlong UTF-8 sequence
                        c = ( *( i + 1 ) ); // look ahead to next byte in sequence
                        if (( c & _lead3 ) == _cont )
                        {
                            //throw invalid_data( "overlong UTF-8 sequence" );
                            return str.size();
                        }
                    }
 
                } else if (( c & ~_lead4_mask ) == _lead4 ) { // 4 additional bytes
                    contBytes = 4;
                    if ( c == _lead4 ) { // possible overlong UTF-8 sequence
                        c = ( *( i + 1 ) ); // look ahead to next byte in sequence
                        if (( c & _lead4 ) == _cont )
                        {
                            //throw invalid_data( "overlong UTF-8 sequence" );
                            return str.size();
                        }
                    }
 
                } else if (( c & ~_lead5_mask ) == _lead5 ) { // 5 additional bytes
                    contBytes = 5;
                    if ( c == _lead5 ) { // possible overlong UTF-8 sequence
                        c = ( *( i + 1 ) ); // look ahead to next byte in sequence
                        if (( c & _lead5 ) == _cont )
                        {
                            //throw invalid_data( "overlong UTF-8 sequence" );
                            return str.size();
                        }
                    }
                }
 
                // check remaining continuation bytes for
                while ( contBytes-- ) {
                    c = ( *( ++i ) ); // get next byte in sequence
                    if (( c & ~_cont_mask ) != _cont )
                    {
                        //throw invalid_data( "bad UTF-8 continuation byte" );
                        return str.size();
                    }
                }
            }
            length++;
            i++;
        }
        return length;
    }
 
    void UString::_init()
    {
        m_buffer.mVoidBuffer = nullptr;
        m_bufferType = bt_none;
        m_bufferSize = 0;
    }
 
    void UString::_cleanBuffer() const
    {
        if ( m_buffer.mVoidBuffer != nullptr ) {
            switch ( m_bufferType ) {
                case bt_string:
                    delete m_buffer.mStrBuffer;
                    break;
                case bt_wstring:
                    delete m_buffer.mWStrBuffer;
                    break;
                case bt_utf32string:
                    delete m_buffer.mUTF32StrBuffer;
                    break;
                case bt_none: // under the worse of circumstances, this is all we can do, and hope it works out
                    //delete m_buffer.mVoidBuffer;
                    // delete void* is undefined, don't do that
                    assert("This should never happen - mVoidBuffer should never contain something if we "
                        "don't know the type");
                    break;
            }
            m_buffer.mVoidBuffer = nullptr;
            m_bufferSize = 0;
            m_bufferType = bt_none;
        }
    }
 
    void UString::_getBufferStr() const
    {
        if ( m_bufferType != bt_string ) {
            _cleanBuffer();
            m_buffer.mStrBuffer = new std::string();
            m_bufferType = bt_string;
        }
        m_buffer.mStrBuffer->clear();
    }
 
    void UString::_getBufferWStr() const
    {
        if ( m_bufferType != bt_wstring ) {
            _cleanBuffer();
            m_buffer.mWStrBuffer = new std::wstring();
            m_bufferType = bt_wstring;
        }
        m_buffer.mWStrBuffer->clear();
    }
 
    void UString::_getBufferUTF32Str() const
    {
        if ( m_bufferType != bt_utf32string ) {
            _cleanBuffer();
            m_buffer.mUTF32StrBuffer = new utf32string();
            m_bufferType = bt_utf32string;
        }
        m_buffer.mUTF32StrBuffer->clear();
    }
 
    void UString::_load_buffer_UTF8() const
    {
        _getBufferStr();
        std::string& buffer = ( *m_buffer.mStrBuffer );
        buffer.reserve( length() );
 
        unsigned char utf8buf[6];
        char* charbuf = ( char* )utf8buf;
        unicode_char c;
        size_t len;
 
        const_iterator i, ie = end();
        for ( i = begin(); i != ie; i.moveNext() ) {
            c = i.getCharacter();
            len = _utf32_to_utf8( c, utf8buf );
            size_t j = 0;
            while ( j < len )
                buffer.push_back( charbuf[j++] );
        }
    }
 
    void UString::_load_buffer_WStr() const
    {
        _getBufferWStr();
        std::wstring& buffer = ( *m_buffer.mWStrBuffer );
        buffer.reserve( length() ); // may over reserve, but should be close enough
#ifdef WCHAR_UTF16 // wchar_t matches UTF-16
        const_iterator i, ie = end();
        for ( i = begin(); i != ie; ++i ) {
            buffer.push_back(( wchar_t )( *i ) );
        }
#else // wchar_t fits UTF-32
        unicode_char c;
        const_iterator i, ie = end();
        for ( i = begin(); i != ie; i.moveNext() ) {
            c = i.getCharacter();
            buffer.push_back(( wchar_t )c );
        }
#endif
    }
 
    void UString::_load_buffer_UTF32() const
    {
        _getBufferUTF32Str();
        utf32string& buffer = ( *m_buffer.mUTF32StrBuffer );
        buffer.reserve( length() ); // may over reserve, but should be close enough
 
        unicode_char c;
 
        const_iterator i, ie = end();
        for ( i = begin(); i != ie; i.moveNext() ) {
            c = i.getCharacter();
            buffer.push_back( c );
        }
    }
 
} // namespace MyGUI