How to get length of UTF8 string

navinkaus · 12-22-2008, 11:12 PM

Is there any API which returns the length of UTF8 string ?

Thanks,
Navin

burschik · 12-23-2008, 01:45 AM

Are we supposed to guess the language?

navinkaus · 12-23-2008, 03:14 AM

My program is in C and looking to get the length of UTF8 encoded string.

navinkaus · 12-23-2008, 03:38 AM

Using following custom function:

int strlen_utf8(char *s)
{
int i = 0, j = 0;
while (s[i])
{
if ((s[i] & 0xc0) != 0x80)
j++;
i++;
}
return j;
}

Let's say if string contains japanese word(5 japanese characters) with 10 bytes at binary level, it will return 5.
In case if string contains 5 ASCII characters (5 bytes at binary level ), it will return 5.

Anybody see any problem in this ?

navinkaus · 12-23-2008, 03:42 AM

one more thing, I googled and read on some website that strlen will work on linux i.e. it understands UTF8 encoded string.

But it's not true, I created a hello world and found that it returns the length till it reached '\0'. So if Japanase word takes 10 characters at binary level after encoding, strlen will return 10 instead of length of printable characters of that japanese word.

Any comments ?

burschik · 12-23-2008, 05:11 AM

You should not believe everything you read on random websites. A more reliable source of information on UTF-8 and related issues is http://www.cl.cam.ac.uk/~mgk25/unicode.html. For your particular needs, http://linux.about.com/library/cmd/blcmdl3_mbstowcs.htm would seem suitable.