ord() doesn't work with utf-8 - php

Question

according to ISO 8859-1
€ Symbol has decimal value 128
My default php script encoding is
echo mb_internal_encoding(); //ISO-8859-1
So now as PHP
echo chr(128); //Output exactly what i want '€'
But
echo ord('€'); //opposite it returns 226, it should be 128
why it is so?

Answer 1

It is only for 2018's PHP v7.2.0+.
mb_ord()
Now you can use mb_ord().
Example echo mb_ord('€','UTF-8');
See also mb_chr(), to get the UTF-8 representation of a decimal code. Example echo mb_chr(2048,'UTF-8');.
The best practice is to be universal, save all your PHP scripts as UTF-8 (see #deceze).

Answer 2

According to Wikipedia and FileFormat,
ISO-8859-1 doesn't have the Euro symbol at all
ISO-8859-15 has it at codepoint 164 (0xA4)
Windows-1252 has it at codepoint 128 (0x80)
Unicode has the Euro symbol at codepoint 8364 (0x20AC)
UTF-8 encodes that as 0xE2 0x82 0xAC. The first byte E2 is 226 in decimal.
So it seems your source file is encoded in UTF-8 (and ord() only returns the first byte), whereas your output is in Windows-1252.

Answer 3

echo ord('€'); //opposite it returns 226, it should be 128
Your .php file is saved as UTF-8 (you saved it as UTF-8 in your text editor when you saved the file to disk). The string literal in there contains the bytes E2 82 AC; visualised it's something like this:
echo ord('\xE2\x82\xAC');
Open the file in a hex editor for real clarity.
ord only returns a single integer in the range of 0 - 255. Your string literal contains three bytes, for which ord would need to return three integers, which it won't. It returns only the first one, which is 226.
Save the file in different encodings in your text editor and you'll see different results.

Answer 4

This PHP function return the decimal number of the first character in string.
If the number is lower than 128 then the character is encoded in 1 octet.
Elseif the number is lower than 2048 then the character is encoded in 2 octets.
Elseif the number is lower than 65536 then the character is encoded in 3 octets.
Elseif the number is lower than 1114112 then the character is encoded in 4 octets.
function ord_utf8($s){
return (int) ($s=unpack('C*',$s[0].$s[1].$s[2].$s[3]))&&$s[1]<(1<<7)?$s[1]:
($s[1]>239&&$s[2]>127&&$s[3]>127&&$s[4]>127?(7&$s[1])<<18|(63&$s[2])<<12|(63&$s[3])<<6|63&$s[4]:
($s[1]>223&&$s[2]>127&&$s[3]>127?(15&$s[1])<<12|(63&$s[2])<<6|63&$s[3]:
($s[1]>193&&$s[2]>127?(31&$s[1])<<6|63&$s[2]:0)));
}
echo ord_utf8('€');
// Output 8364 then this character is encoded in 3 octets
You can check the result in https://eval.in/748181 …
The ord_utf8 function is the reciprocal of chr_utf8 (print one utf8 character from decimal number)
function chr_utf8($n,$f='C*'){
return $n<(1<<7)?chr($n):($n<1<<11?pack($f,192|$n>>6,1<<7|191&$n):
($n<(1<<16)?pack($f,224|$n>>12,1<<7|63&$n>>6,1<<7|63&$n):
($n<(1<<20|1<<16)?pack($f,240|$n>>18,1<<7|63&$n>>12,1<<7|63&$n>>6,1<<7|63&$n):'')));
}
for($test=1;$test<1114111;$test++)
if (ord_utf8(chr_utf8($test))!==$test)
die('Error found');
echo 'No error';
// Output No error