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 std.conv;
import std.stdio;
 
immutable CHARS = ["A","ö","Ж","€","𝄞"];
 
void main() {
    writeln("Character   Code-Point   Code-Units");
    foreach (c; CHARS) {
        auto bytes = cast(ubyte[]) c; //The raw bytes of a character can be accessed by casting
        auto unicode = cast(uint) to!dstring(c)[0]; //Convert from a UTF8 string to a UTF32 string, and cast the first character to a number
        writefln("%s              %7X   [%(%X, %)]", c, unicode, bytes);
    }
}