/* version.c	version handling
 * Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
 * Copyright (C) 2002  Simon Josefsson
 *
 * This file is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This file 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this file; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

/* This file is based on src/global.c from Werner Koch's libgcrypt */

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

static const char*
parse_version_number( const char *s, int *number )
{
    int val = 0;

    if( *s == '0' && isdigit(s[1]) )
	return NULL; /* leading zeros are not allowed */
    for ( ; isdigit(*s); s++ ) {
	val *= 10;
	val += *s - '0';
    }
    *number = val;
    return val < 0? NULL : s;
}


static const char *
parse_version_string( const char *s, int *major, int *minor, int *micro )
{
    s = parse_version_number( s, major );
    if( !s || *s != '.' )
	return NULL;
    s++;
    s = parse_version_number( s, minor );
    if( !s || *s != '.' )
	return NULL;
    s++;
    s = parse_version_number( s, micro );
    if( !s )
	return NULL;
    return s; /* patchlevel */
}

/****************
 * Check that the the version of the library is at minimum the requested one
 * and return the version string; return NULL if the condition is not
 * satisfied.  If a NULL is passed to this function, no check is done,
 * but the version string is simply returned.
 */
const char *
ntlm_check_version( const char *req_version )
{
    const char *ver = VERSION;
    int my_major, my_minor, my_micro;
    int rq_major, rq_minor, rq_micro;
    const char *my_plvl, *rq_plvl;

    if ( !req_version )
	return ver;

    my_plvl = parse_version_string( ver, &my_major, &my_minor, &my_micro );
    if ( !my_plvl )
	return NULL;  /* very strange our own version is bogus */
    rq_plvl = parse_version_string( req_version, &rq_major, &rq_minor,
								&rq_micro );
    if ( !rq_plvl )
	return NULL;  /* req version string is invalid */

    if ( my_major > rq_major
	|| (my_major == rq_major && my_minor > rq_minor)
	|| (my_major == rq_major && my_minor == rq_minor
				 && my_micro > rq_micro)
	|| (my_major == rq_major && my_minor == rq_minor
				 && my_micro == rq_micro
				 && strcmp( my_plvl, rq_plvl ) >= 0) ) {
	return ver;
    }
    return NULL;
}