169 lines
3.9 KiB
C
169 lines
3.9 KiB
C
/*
|
|
* Copyright (c) 2000 Silicon Graphics, Inc. All Rights Reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of version 2 of the GNU General Public License as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it would be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
|
*
|
|
* Further, this software is distributed without any warranty that it is
|
|
* free of the rightful claim of any third person regarding infringement
|
|
* or the like. Any license provided herein, whether implied or
|
|
* otherwise, applies only to this software file. Patent licenses, if
|
|
* any, provided herein do not apply to combinations of this program with
|
|
* other software, or any other product whatsoever.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write the Free Software Foundation, Inc., 59
|
|
* Temple Place - Suite 330, Boston MA 02111-1307, USA.
|
|
*
|
|
* Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
|
|
* Mountain View, CA 94043, or:
|
|
*
|
|
* http://www.sgi.com
|
|
*
|
|
* For further information regarding this notice, see:
|
|
*
|
|
* http://oss.sgi.com/projects/GenInfo/NoticeExplan/
|
|
*/
|
|
#include <string.h>
|
|
#include "pattern.h"
|
|
|
|
/*
|
|
* The routines in this module are used to fill/check a data buffer
|
|
* with/against a known pattern.
|
|
*/
|
|
|
|
int
|
|
pattern_check(buf, buflen, pat, patlen, patshift)
|
|
char *buf;
|
|
int buflen;
|
|
char *pat;
|
|
int patlen;
|
|
int patshift;
|
|
{
|
|
int nb, ncmp, nleft;
|
|
char *cp;
|
|
|
|
if (patlen)
|
|
patshift = patshift % patlen;
|
|
|
|
cp = buf;
|
|
nleft = buflen;
|
|
|
|
/*
|
|
* The following 2 blocks of code are to compare the first patlen
|
|
* bytes of buf. We need 2 checks if patshift is > 0 since we
|
|
* must check the last (patlen - patshift) bytes, and then the
|
|
* first (patshift) bytes.
|
|
*/
|
|
|
|
nb = patlen - patshift;
|
|
if (nleft < nb) {
|
|
return (memcmp(cp, pat + patshift, nleft) ? -1 : 0);
|
|
} else {
|
|
if (memcmp(cp, pat + patshift, nb))
|
|
return -1;
|
|
|
|
nleft -= nb;
|
|
cp += nb;
|
|
}
|
|
|
|
if (patshift > 0) {
|
|
nb = patshift;
|
|
if (nleft < nb) {
|
|
return (memcmp(cp, pat, nleft) ? -1 : 0);
|
|
} else {
|
|
if (memcmp(cp, pat, nb))
|
|
return -1;
|
|
|
|
nleft -= nb;
|
|
cp += nb;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Now, verify the rest of the buffer using the algorithm described
|
|
* in the function header.
|
|
*/
|
|
|
|
ncmp = cp - buf;
|
|
while (ncmp < buflen) {
|
|
nb = (ncmp < nleft) ? ncmp : nleft;
|
|
if (memcmp(buf, cp, nb))
|
|
return -1;
|
|
|
|
cp += nb;
|
|
ncmp += nb;
|
|
nleft -= nb;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
pattern_fill(buf, buflen, pat, patlen, patshift)
|
|
char *buf;
|
|
int buflen;
|
|
char *pat;
|
|
int patlen;
|
|
int patshift;
|
|
{
|
|
int trans, ncopied, nleft;
|
|
char *cp;
|
|
|
|
if (patlen)
|
|
patshift = patshift % patlen;
|
|
|
|
cp = buf;
|
|
nleft = buflen;
|
|
|
|
/*
|
|
* The following 2 blocks of code are to fill the first patlen
|
|
* bytes of buf. We need 2 sections if patshift is > 0 since we
|
|
* must first copy the last (patlen - patshift) bytes into buf[0]...,
|
|
* and then the first (patshift) bytes of pattern following them.
|
|
*/
|
|
|
|
trans = patlen - patshift;
|
|
if (nleft < trans) {
|
|
memcpy(cp, pat + patshift, nleft);
|
|
return 0;
|
|
} else {
|
|
memcpy(cp, pat + patshift, trans);
|
|
nleft -= trans;
|
|
cp += trans;
|
|
}
|
|
|
|
if (patshift > 0) {
|
|
trans = patshift;
|
|
if (nleft < trans) {
|
|
memcpy(cp, pat, nleft);
|
|
return 0;
|
|
} else {
|
|
memcpy(cp, pat, trans);
|
|
nleft -= trans;
|
|
cp += trans;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Now, fill the rest of the buffer using the algorithm described
|
|
* in the function header comment.
|
|
*/
|
|
|
|
ncopied = cp - buf;
|
|
while (ncopied < buflen) {
|
|
trans = (ncopied < nleft) ? ncopied : nleft;
|
|
memcpy(cp, buf, trans);
|
|
cp += trans;
|
|
ncopied += trans;
|
|
nleft -= trans;
|
|
}
|
|
|
|
return(0);
|
|
}
|