Should there be something like 'bytelen' (along with 'strlen')? - php4

Question

In my opinion the 'strlen' function should only return the number of characters in a string. Nothing else. And it does, whether it counts ASCII characters or Unicode characters. A character is a character, pointing to a given position on an ASCII table or a UTF-8 table. Nothing more.
If you would like to know, for whatever reason, the byte-length of a string, then you should use a differtent function. I am a newby in PHP scripting, so I did not find that function yet. (Should be something like 'bytelen()'?)

Answer 1

mb_strlen() does what you're after.

Answer 2

Yes, that would be most logical design. However, PHP has not been planned to support multibyte charsets from the beginning. Instead, it's been evolving along the years in a sort of chaotic manner. You've tagged your question as PHP 4 but PHP 5 does not have a decent Unicode support yet (and I don't think it'll change in a nearby future).
There're a few reasons for this anyway:
PHP is not a closed-source commercial product owned by a company with a centralized design controlled by enterprise rules.
PHP was released in 1995 as a personal project by someone who needed some functionality in his static home page: at that time, it had no need for Unicode support.
If you modify core functions like strlen() you must do it in a way that it doesn't break previous functionality. It's not easy. Writing a new separate function is much easier.
Update
Sorry, I forgot the second part of your question. If you need to handle Unicode strings you have to use a separate set of functions:
http://es.php.net/manual/en/book.mbstring.php
You might also find these chapters interesting:
http://es.php.net/manual/en/book.iconv.php
http://es.php.net/manual/en/book.unicode.php
Please take note of the PHP version required by each function you are planning to use; PHP 4 is pretty old.

Answer 3

If I'm not grossly misunderstanding you, then strlen() is your 'bytelen()', as alluded to in the other responses here.
strlen() itself has no support for utf-8 or other multi-byte character sets; if you want a proper strlen(), you'll need mb_strlen().
Pentium10's function strBytes($str), from glancing over it (not testing) looks like it would be a good alternative if you know your encoding is utf-8 and you're stuck with a super low version of PHP4 for some reason.
(And I do recommend taking a look at Álvaro G. Vicario's post for the reasons behind this behaviour. Proper, native UTF-8 support is due to come with PHP6.)

Answer 4

/**
* Count the number of bytes of a given string.
* Input string is expected to be ASCII or UTF-8 encoded.
* Warning: the function doesn't return the number of chars
* in the string, but the number of bytes.
*
* #param string $str The string to compute number of bytes
*
* #return The length in bytes of the given string.
*/
function strBytes($str)
{
// STRINGS ARE EXPECTED TO BE IN ASCII OR UTF-8 FORMAT
// Number of characters in string
$strlen_var = strlen($str);
// string bytes counter
$d = 0;
/*
* Iterate over every character in the string,
* escaping with a slash or encoding to UTF-8 where necessary
*/
for ($c = 0; $c < $strlen_var; ++$c) {
$ord_var_c = ord($str{$d});
switch (true) {
case (($ord_var_c >= 0x20) && ($ord_var_c <= 0x7F)):
// characters U-00000000 - U-0000007F (same as ASCII)
$d++;
break;
case (($ord_var_c & 0xE0) == 0xC0):
// characters U-00000080 - U-000007FF, mask 110XXXXX
// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
$d+=2;
break;
case (($ord_var_c & 0xF0) == 0xE0):
// characters U-00000800 - U-0000FFFF, mask 1110XXXX
// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
$d+=3;
break;
case (($ord_var_c & 0xF8) == 0xF0):
// characters U-00010000 - U-001FFFFF, mask 11110XXX
// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
$d+=4;
break;
case (($ord_var_c & 0xFC) == 0xF8):
// characters U-00200000 - U-03FFFFFF, mask 111110XX
// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
$d+=5;
break;
case (($ord_var_c & 0xFE) == 0xFC):
// characters U-04000000 - U-7FFFFFFF, mask 1111110X
// see http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
$d+=6;
break;
default:
$d++;
}
}
return $d;
}