//
//  FreeTar
//  NSString_PathUtils.m
//
//  Copyright (c) 2002 Murray M Johnson
//
//	http://homepage.mac.com/mjsoftware/
//	mjsoftware@mac.com
//
//
//  This file is part of FreeTar version 1.1.
//
//  FreeTar is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation; either version 2 of the License, or
//  (at your option) any later version.
//
//  FreeTar 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 FreeTar; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//

#import "NSString_PathUtils.h"


@implementation NSString(PathUtils)

- (NSString*) pathRelativeTo:(NSString*)baseDir
{
	NSArray*		base_cmpnts;
	NSArray*		self_cmpnts;
	NSMutableArray*	output_cmpnts;
	int				c;
	int				start_c1;
	int				start_c2;


	// split baseDir into it's components
	base_cmpnts = [baseDir pathComponents];

	// split self into it's components
	self_cmpnts = [self pathComponents];

	// allocate output components
	output_cmpnts = [NSMutableArray arrayWithCapacity:[self_cmpnts count]];


	// figure out how many directories to back up:
	start_c1 = [base_cmpnts count] - 1;
	if([self_cmpnts count] - 2 < start_c1)
		start_c1 = [self_cmpnts count] - 2;

	start_c2 = 0;
	for(c = start_c1; c >= 0; --c)
	{
		if( (c >= [base_cmpnts count] && c < [self_cmpnts count]) ||
	  (c < [base_cmpnts count] && c >= [self_cmpnts count]) ||
	  (![[base_cmpnts objectAtIndex:c] isEqualToString:[self_cmpnts objectAtIndex:c]]))
		{
			// need to go back one directory
			[output_cmpnts addObject:@".."];
		}
		else
		{
			// paths are the same at this index, we can stop

			// set start_c for next loop
			start_c2 = c + 1;

			// stop loop
			break;
		}
	}


	// now loop to add the forward directories
	for(c = start_c2; c < [self_cmpnts count]; ++c)
	{
		[output_cmpnts addObject:[self_cmpnts objectAtIndex:c]];
	}

    return [NSString pathWithComponents:output_cmpnts];
}

@end