/*
 *	tardy - a tar post-processor
 *	Copyright (C) 1998, 1999, 2002 Peter Miller;
 *	All rights reserved.
 *
 *	This program 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.
 *
 *	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., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 * MANIFEST: functions to manipulate cannonical path names
 */

#include <ac/assert.h>

#include <cannonical.h>


rcstring
cannonicalize(const rcstring &in)
{
	rcstring out;
	rcstring path_text;
	const char *path_pos = in.to_c_string();
	enum path_token_ty { path_dot, path_slash, path_name, path_end };
	path_token_ty path_token;

	int state = 0;
	while (state >= 0)
	{
		/*
		 * figure the next token in the path
		 */
		switch (*path_pos)
		{
		case 0:
			path_text = "";
			path_token = path_end;
			break;
		
		case '/':
			++path_pos;
			while (*path_pos == '/')
				++path_pos;
			path_text = "/";
			path_token = path_slash;
			break;
	
		default:
			const char *cp = path_pos;
			for (;;)
			{
				++path_pos;
				if (!*path_pos || *path_pos == '/')
					break;
			}
			path_text = rcstring(cp, path_pos - cp);
			static rcstring dot(".");
			if (path_text == dot)
				path_token = path_dot;
			else
				path_token = path_name;
			break;
		}

		/*
		 * do something with the token
		 */
		switch (path_token)
		{
		case path_dot:
			switch (state)
			{
			case 0:
			case 2:
				++state;
				break;

			default:
				assert(0);
				state = -1;
				break;
			}
			break;

		case path_name:
			switch (state)
			{
			case 0:
				out += path_text;
				state = 4;
				break;
				
			case 2:
				out += "/";
				out += path_text;
				state = 4;
				break;
			
			default:
				assert(0);
				state = -1;
				break;
			}
			break;

		case path_slash:
			switch (state)
			{
			case 0:
			case 3:
			case 4:
				state = 2;
				break;

			case 1:
				state = 0;
				break;

			default:
				assert(0);
				state = -1;
				break;
			}
			break;

		case path_end:
			switch (state)
			{
			case 0:
			case 1:
				out += ".";
				break;
			}
			state = -1;
			break;
		}
	}
	return out;
}