UTF-8 encode and decode: Difference between revisions

</pre>

=={{header|Wren}}==

The utf8_decode function was translated from the Go entry.

<lang ecmascript>import "/fmt" for Fmt

var utf8_encode = Fn.new { |cp| String.fromCodePoint(cp).bytes.toList }

var utf8_decode = Fn.new { |b|

var mbMask = 0x3f // non-first bytes start 10 and carry 6 bits of data

var b0 = b[0]

if (b0 < 0x80) {

return b0

} else if (b0 < 0xe0) {

var b2Mask = 0x1f // first byte of a 2-byte encoding starts 110 and carries 5 bits of data

return (b0 & b2Mask) << 6 | (b[1] & mbMask)

} else if (b0 < 0xf0) {

var b3Mask = 0x0f // first byte of a 3-byte encoding starts 1110 and carries 4 bits of data

return (b0 & b3Mask) << 12 | (b[1] & mbMask) << 6 | (b[2] & mbMask)

} else {

var b4Mask = 0x07 // first byte of a 4-byte encoding starts 11110 and carries 3 bits of data

return (b0 & b4Mask) << 18 | (b[1] & mbMask) << 12 | (b[2] & mbMask) << 6 | (b[3] & mbMask)

}

}

var tests = [

["LATIN CAPITAL LETTER A", 0x41],

["LATIN SMALL LETTER O WITH DIAERESIS", 0xf6],

["CYRILLIC CAPITAL LETTER ZHE", 0x416],

["EURO SIGN", 0x20ac],

["MUSICAL SYMBOL G CLEF", 0x1d11e]

]

System.print("Character Name Unicode UTF-8 encoding (hex)")

System.print("---------------------------------------------------------------------------------")

for (test in tests) {

var cp = test[1]

var bytes = utf8_encode.call(cp)

var utf8 = bytes.map { |b| Fmt.Xz(2, b) }.join(" ")

var cp2 = utf8_decode.call(bytes)

var uni = String.fromCodePoint(cp2)

System.print("%(Fmt.s(-11, uni)) %(Fmt.s(-37, test[0])) U+%(Fmt.s(-8, Fmt.Xz(4, cp2))) %(utf8)")

}</lang>

{{out}}

<pre>

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