libc/newlib/libc/string/strnlen.c

/* 
FUNCTION
	<<strnlen>>---character string length
	
INDEX
	strnlen

SYNOPSIS
	#include <string.h>
	size_t strnlen(const char *<[str]>, size_t <[n]>);

DESCRIPTION
	The <<strnlen>> function works out the length of the string
	starting at <<*<[str]>>> by counting chararacters until it
	reaches a NUL character or the maximum: <[n]> number of
        characters have been inspected.

RETURNS
	<<strnlen>> returns the character count or <[n]>.

PORTABILITY
<<strnlen>> is a GNU extension.

<<strnlen>> requires no supporting OS subroutines.

*/

#undef __STRICT_ANSI__
#include <_ansi.h>
#include <string.h>

size_t
strnlen (const char *str,
	size_t n)
{
  const char *start = str;

  while (n-- > 0 && *str)
    str++;

  return str - start;
}