newlib-cygwin/newlib/libc/string/wcsncasecmp.c

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/*
FUNCTION
<<wcsncasecmp>>---case-insensitive wide character string compare
INDEX
wcsncasecmp
ANSI_SYNOPSIS
#include <wchar.h>
int wcsncasecmp(const wchar_t *<[a]>, const wchar_t * <[b]>, size_t <[length]>);
TRAD_SYNOPSIS
#include <wchar.h>
int wcsncasecmp(<[a]>, <[b]>, <[length]>)
wchar_t *<[a]>;
wchar_t *<[b]>;
size_t <[length]>
DESCRIPTION
<<wcsncasecmp>> compares up to <[length]> wide characters
from the string at <[a]> to the string at <[b]> in a
case-insensitive manner.
RETURNS
If <<*<[a]>>> sorts lexicographically after <<*<[b]>>> (after
both are converted to uppercase), <<wcsncasecmp>> returns a
number greater than zero. If the two strings are equivalent,
<<wcsncasecmp>> returns zero. If <<*<[a]>>> sorts
lexicographically before <<*<[b]>>>, <<wcsncasecmp>> returns a
number less than zero.
PORTABILITY
POSIX-1.2008
<<wcsncasecmp>> requires no supporting OS subroutines. It uses
tolower() from elsewhere in this library.
QUICKREF
wcsncasecmp
*/
#include <wchar.h>
#include <wctype.h>
int
_DEFUN (wcsncasecmp, (s1, s2, n),
_CONST wchar_t *s1 _AND
_CONST wchar_t *s2 _AND
size_t n)
{
if (n == 0)
return 0;
while (n-- != 0 && towlower(*s1) == towlower(*s2))
{
if (n == 0 || *s1 == '\0' || *s2 == '\0')
break;
s1++;
s2++;
}
return towlower(*s1) - towlower(*s2);
}