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.

constant tests = {#0041, #00F6, #0416, #20AC, #1D11E}
 
function hex(sequence s, string fmt)    -- output helper
    return join(apply(true,sprintf,{{fmt},s}),',')
end function
 
for i=1 to length(tests) do
    integer codepoint = tests[i]
    sequence s = utf32_to_utf8({codepoint}),
             r = utf8_to_utf32(s)
    printf(1,"#%04x -> {%s} -> {%s}\n",{codepoint, hex(s,"#%02x"),hex(r,"#%04x")})
end for
