public static int UTF16toUTF8()

in lightning-core/src/main/java/org/apache/directmemory/lightning/internal/util/UnicodeUtil.java [154:219]
55 lines of code
9 McCabe index (conditional complexity)

    public static int UTF16toUTF8( String value, Target target )
        throws IOException
    {
        char[] characters = value.toCharArray();
        int length = characters.length;

        // Write string length to target
        target.writeInt( length );

        int i = 0;
        final int end = length;

        int writtenBytes = 0;
        while ( i < end )
        {

            final int code = characters[i++];

            if ( code < 0x80 )
            {
                target.writeByte( (byte) code );
                writtenBytes++;
            }
            else if ( code < 0x800 )
            {
                target.writeByte( (byte) ( 0xC0 | ( code >> 6 ) ) );
                target.writeByte( (byte) ( 0x80 | ( code & 0x3F ) ) );
                writtenBytes += 2;
            }
            else if ( code < 0xD800 || code > 0xDFFF )
            {
                target.writeByte( (byte) ( 0xE0 | ( code >> 12 ) ) );
                target.writeByte( (byte) ( 0x80 | ( ( code >> 6 ) & 0x3F ) ) );
                target.writeByte( (byte) ( 0x80 | ( code & 0x3F ) ) );
                writtenBytes += 3;
            }
            else
            {
                // surrogate pair
                // confirm valid high surrogate
                if ( code < 0xDC00 && i < end )
                {
                    int utf32 = characters[i];
                    // confirm valid low surrogate and write pair
                    if ( utf32 >= 0xDC00 && utf32 <= 0xDFFF )
                    {
                        utf32 = ( code << 10 ) + utf32 + SURROGATE_OFFSET;
                        i++;
                        target.writeByte( (byte) ( 0xF0 | ( utf32 >> 18 ) ) );
                        target.writeByte( (byte) ( 0x80 | ( ( utf32 >> 12 ) & 0x3F ) ) );
                        target.writeByte( (byte) ( 0x80 | ( ( utf32 >> 6 ) & 0x3F ) ) );
                        target.writeByte( (byte) ( 0x80 | ( utf32 & 0x3F ) ) );
                        writtenBytes += 4;
                        continue;
                    }
                }
                // replace unpaired surrogate or out-of-order low surrogate
                // with substitution character
                target.writeByte( (byte) 0xEF );
                target.writeByte( (byte) 0xBF );
                target.writeByte( (byte) 0xBD );
                writtenBytes += 3;
            }
        }
        return writtenBytes;
    }