jehanne/sys/src/lib/jehanne/port/utfnlen.c

36 lines
773 B
C

/*
* This file is part of the UCB release of Plan 9. It is subject to the license
* terms in the LICENSE file found in the top-level directory of this
* distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
* part of the UCB release of Plan 9, including this file, may be copied,
* modified, propagated, or distributed except according to the terms contained
* in the LICENSE file.
*/
#include <u.h>
#include <libc.h>
int
jehanne_utfnlen(const char *s, int32_t m)
{
int c;
int32_t n;
Rune rune;
const char *es;
es = s + m;
for(n = 0; s < es; n++) {
c = *(uint8_t*)s;
if(c < Runeself){
if(c == '\0')
break;
s++;
continue;
}
if(!jehanne_fullrune(s, es-s))
break;
s += jehanne_chartorune(&rune, s);
}
return n;
}