telnetd/libtelnet/genget.c

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/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#ifndef lint
#if 0
static const char sccsid[] = "@(#)genget.c 8.2 (Berkeley) 5/30/95";
#endif
#endif /* not lint */
#include <ctype.h>
#define LOWER(x) (isupper(x) ? tolower(x) : (x))
/*
* The prefix function returns 0 if *s1 is not a prefix
* of *s2. If *s1 exactly matches *s2, the negative of
* the length is returned. If *s1 is a prefix of *s2,
* the length of *s1 is returned.
*/
int
isprefix(char *s1, char *s2)
{
char *os1;
char c1, c2;
if (*s1 == '\0')
return(-1);
os1 = s1;
c1 = *s1;
c2 = *s2;
while (LOWER(c1) == LOWER(c2)) {
if (c1 == '\0')
break;
c1 = *++s1;
c2 = *++s2;
}
return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
}
static char *ambiguous; /* special return value for command routines */
char **
genget(char *name, char **table, int stlen)
{
char **c, **found;
int n;
if (name == 0)
return 0;
found = 0;
for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
if ((n = isprefix(name, *c)) == 0)
continue;
if (n < 0) /* exact match */
return(c);
if (found)
return(&ambiguous);
found = c;
}
return(found);
}
/*
* Function call version of Ambiguous()
*/
int
Ambiguous(char *s)
{
return((char **)s == &ambiguous);
}