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.

import system'routines;
import extensions;
 
extension op : String
{
    string printAsString()
    {
       console.print(self," ")
    }
 
    string printAsUTF8Array()
    {
        self.toByteArray().forEach:(b){ console.print(b.toString(16)," ") }
    }
 
    string printAsUTF32()
    {
        self.toArray().forEach:(c){ console.print("U+",c.toInt().toString(16)," ") }
    }
}
 
public program()
{
    "A".printAsString().printAsUTF8Array().printAsUTF32();
    console.printLine();
 
    "ö".printAsString().printAsUTF8Array().printAsUTF32();
    console.printLine();
 
    "Ж".printAsString().printAsUTF8Array().printAsUTF32();
    console.printLine();
 
    "€".printAsString().printAsUTF8Array().printAsUTF32();
    console.printLine();
 
    "𝄞".printAsString().printAsUTF8Array().printAsUTF32();
    console.printLine();
}