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

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/*
FUNCTION
<<strncasecmp>>---case-insensitive character string compare
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INDEX
strncasecmp
ANSI_SYNOPSIS
#include <string.h>
int strncasecmp(const char *<[a]>, const char * <[b]>, size_t <[length]>);
TRAD_SYNOPSIS
#include <string.h>
int strncasecmp(<[a]>, <[b]>, <[length]>)
char *<[a]>;
char *<[b]>;
size_t <[length]>
DESCRIPTION
<<strncasecmp>> compares up to <[length]> 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), <<strncasecmp>> returns a
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number greater than zero. If the two strings are equivalent,
<<strncasecmp>> returns zero. If <<*<[a]>>> sorts
lexicographically before <<*<[b]>>>, <<strncasecmp>> returns a
number less than zero.
PORTABILITY
<<strncasecmp>> is in the Berkeley Software Distribution.
<<strncasecmp>> requires no supporting OS subroutines. It uses
tolower() from elsewhere in this library.
QUICKREF
strncasecmp
*/
#include <string.h>
#include <ctype.h>
int
_DEFUN (strncasecmp, (s1, s2, n),
_CONST char *s1 _AND
_CONST char *s2 _AND
size_t n)
{
if (n == 0)
return 0;
while (n-- != 0 && tolower(*s1) == tolower(*s2))
{
if (n == 0 || *s1 == '\0' || *s2 == '\0')
break;
s1++;
s2++;
}
return tolower(*(unsigned char *) s1) - tolower(*(unsigned char *) s2);
}