# OpenVAS Vulnerability Test include file
# $Id$
# Description: Revision string comparison helper function
#
# Authors:
# Thomas Reinke <reinke@securityspace.com>
#
# Copyright:
# Copyright (c) 2007 E-Soft Inc. http://www.securityspace.com
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License Version 2
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#

# Include that can be used to compare two software package version
# strings.  Version string comparison operates on a slightly
# different set or ordering rules:  Instead of comparing character
# by character exclusively throughout the whole string, we instead
# compare character by character until we run into a numeric, at
# which point we extract the entire numeric, and do a numeric
# comparison.  That allows things like  v10.1 to be greather than
# v9, whereas any other string comparison would result in v9
# being larger, because '9' is larger than '1'. Typical strcmp
# return values (0=; -1<; 1>;)

function isdigit(a) {
    if(ord(a)>=ord('0') && ord(a)<=ord('9')) {
	return(1);
    }
    return(0);
}

function revcomp(a, b) {
    if(a == b) {
	return(0);
    }
    done = 0;
    work_a = a;
    work_b = b;
    rc = 0;
    while(!done) {
	lena = strlen(work_a);
	lenb = strlen(work_b);
	if(lena==0) {
	    if(lenb>0) {
		rc = -1;
		break;
	    }
	    if(lenb==0) {
		break;
	    }
	}
	for(i=0; i<lena; i++) {
	    if(i>=lenb) {
		done = 1;
		rc = 1;
		break;
	    }
	    if(isdigit(a:work_a[i]) && isdigit(a:work_b[i])) {
		subm_a=eregmatch(pattern:"([0-9]+)",string:substr(work_a,i));
		subm_b=eregmatch(pattern:"([0-9]+)",string:substr(work_b,i));
		sub_a = subm_a[1];
		sub_b = subm_b[1];
		work_a = substr(work_a, i+strlen(sub_a));
		work_b = substr(work_b, i+strlen(sub_b));
		if(int(sub_a)>int(sub_b)) {
		    done = 1;
		    rc = 1;
		    break;
		}
		if(int(sub_a)<int(sub_b)) {
		    done = 1;
		    rc = -1;
		    break;
		}
		if(int(sub_a)==int(sub_b)) {
		    if(work_a[0]=='.' && work_b[0]!='.') {
			done = 1;
			rc = 1;
			break;
		    }
		    if(work_a[0]!='.' && work_b[0]=='.') {
			done = 1;
			rc = -1;
			break;
		    }
		    # Both must be dots.  Allow the check to proceed normally.
		    break;
		}
	    }
	    if(ord(work_a[i])<ord(work_b[i])) {
		done = 1;
		rc = -1;
		break;
	    }
	    if(ord(work_a[i])>ord(work_b[i])) {
		done = 1;
		rc = 1;
		break;
	    }
	    if(i==lena-1 && lenb>lena) {
		done = 1;
		rc = -1;
		break;
	    }
	}
    }
    return(rc);
}
