As described in UTF-8 and in Wikipedia, UTF-8 is a popular encoding of (multi-byte) Unicode code-points into eight-bit octets.

The goal of this task is to write a encoder that takes a unicode code-point (an integer representing a unicode character) and returns a sequence of 1-4 bytes representing that character in the UTF-8 encoding.

Then you have to write the corresponding decoder that takes a sequence of 1-4 UTF-8 encoded bytes and return the corresponding unicode character.

Demonstrate the functionality of your encoder and decoder on the following five characters:

Character   Name                                  Unicode    UTF-8 encoding (hex)
---------------------------------------------------------------------------------
A           LATIN CAPITAL LETTER A                U+0041     41
ö           LATIN SMALL LETTER O WITH DIAERESIS   U+00F6     C3 B6
Ж           CYRILLIC CAPITAL LETTER ZHE           U+0416     D0 96
€           EURO SIGN                             U+20AC     E2 82 AC
𝄞           MUSICAL SYMBOL G CLEF                 U+1D11E    F0 9D 84 9E

Provided below is a reference implementation in Common Lisp.

: showbytes ( c-addr u -- )
    over + swap ?do
	i c@ 3 .r loop ;
 
: test {: xc -- :}
    xc xemit xc 6 .r xc pad xc!+ pad tuck - ( c-addr u )
    2dup showbytes drop xc@+ xc <> abort" test failed" drop cr ;
 
hex
$41 test $f6 test $416 test $20ac test $1d11e test
\ can also be written as
\ 'A' test 'ö' test 'Ж' test '€' test '𝄞' test
 