From 01c165cd1b2ac601d5ae73d3cb5e82ccdd94ac94 Mon Sep 17 00:00:00 2001 From: Le Chi Thu Date: Tue, 3 Apr 2012 01:23:00 +0200 Subject: Initial commit --- ltp_framework/include/pattern.h | 90 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) create mode 100644 ltp_framework/include/pattern.h (limited to 'ltp_framework/include/pattern.h') diff --git a/ltp_framework/include/pattern.h b/ltp_framework/include/pattern.h new file mode 100644 index 0000000..29c75d3 --- /dev/null +++ b/ltp_framework/include/pattern.h @@ -0,0 +1,90 @@ +/* + * 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/ + */ +#ifndef _PATTERN_H_ +#define _PATTERN_H_ + +/* + * pattern_check(buf, buflen, pat, patlen, patshift) + * + * Check a buffer of length buflen against repeated occurrances of + * a pattern whose length is patlen. Patshift can be used to rotate + * the pattern by patshift bytes to the left. + * + * Patshift may be greater than patlen, the pattern will be rotated by + * (patshift % patshift) bytes. + * + * pattern_check returns -1 if the buffer does not contain repeated + * occurrances of the indicated pattern (shifted by patshift). + * + * The algorithm used to check the buffer relies on the fact that buf is + * supposed to be repeated copies of pattern. The basic algorithm is + * to validate the first patlen bytes of buf against the pat argument + * passed in - then validate the next patlen bytes against the 1st patlen + * bytes - the next (2*patlen) bytes against the 1st (2*pathen) bytes, and + * so on. This algorithm only works when the assumption of a buffer full + * of repeated copies of a pattern holds, and gives MUCH better results + * then walking the buffer byte by byte. + * + * Performance wise, It appears to be about 5% slower than doing a straight + * memcmp of 2 buffers, but the big win is that it does not require a + * 2nd comparison buffer, only the pattern. + */ +int pattern_check( char * , int , char * , int , int ); + +/* + * pattern_fill(buf, buflen, pat, patlen, patshift) + * + * Fill a buffer of length buflen with repeated occurrances of + * a pattern whose length is patlen. Patshift can be used to rotate + * the pattern by patshift bytes to the left. + * + * Patshift may be greater than patlen, the pattern will be rotated by + * (patshift % patlen) bytes. + * + * If buflen is not a multiple of patlen, a partial pattern will be written + * in the last part of the buffer. This implies that a buffer which is + * shorter than the pattern length will receive only a partial pattern ... + * + * pattern_fill always returns 0 - no validation of arguments is done. + * + * The algorithm used to fill the buffer relies on the fact that buf is + * supposed to be repeated copies of pattern. The basic algorithm is + * to fill the first patlen bytes of buf with the pat argument + * passed in - then copy the next patlen bytes with the 1st patlen + * bytes - the next (2*patlen) bytes with the 1st (2*pathen) bytes, and + * so on. This algorithm only works when the assumption of a buffer full + * of repeated copies of a pattern holds, and gives MUCH better results + * then filling the buffer 1 byte at a time. + */ +int pattern_fill( char * , int , char * , int , int ); + +#endif -- cgit v1.2.3