//
// VMime library (http://www.vmime.org)
// Copyright (C) 2002 Vincent Richard <vincent@vmime.org>
//
// 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 3 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.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// Linking this library statically or dynamically with other modules is making
// a combined work based on this library.  Thus, the terms and conditions of
// the GNU General Public License cover the whole combination.
//

#include "vmime/utility/urlUtils.hpp"
#include "vmime/parserHelpers.hpp"


namespace vmime {
namespace utility {


const string urlUtils::encode(const string& s) {

	static const string RESERVED_CHARS =
		/* reserved */ "$&+,/:;=?@"
		/* unsafe */   "<>#%{}[]|\\^\"~`";

	string result;
	result.reserve(s.length());

	for (string::const_iterator it = s.begin() ; it != s.end() ; ++it) {

		const char c = *it;

		if (parserHelpers::isPrint(c) && !parserHelpers::isSpace(c) &&
		    static_cast <unsigned char>(c) <= 127 &&
		    RESERVED_CHARS.find(c) == string::npos) {

			result += c;

		} else {

			char hex[4];
			const unsigned char k = static_cast <unsigned char>(c);

			hex[0] = '%';
			hex[1] = "0123456789ABCDEF"[k / 16];
			hex[2] = "0123456789ABCDEF"[k % 16];
			hex[3] = 0;

			result += hex;
		}
	}

	return result;
}


const string urlUtils::decode(const string& s) {

	string result;
	result.reserve(s.length());

	for (string::const_iterator it = s.begin() ; it != s.end() ; ) {

		const char c = *it;

		switch (c) {

			case '%': {

				++it;  // skip '%'

				const char_t p = (it != s.end() ? *(it++) : 0);
				const char_t q = (it != s.end() ? *(it++) : 0);

				unsigned int r = 0;

				switch (p) {

					case 0: r = '%'; break;
					case 'a': case 'A': r = 10; break;
					case 'b': case 'B': r = 11; break;
					case 'c': case 'C': r = 12; break;
					case 'd': case 'D': r = 13; break;
					case 'e': case 'E': r = 14; break;
					case 'f': case 'F': r = 15; break;
					default: r = p - '0'; break;
				}

				if (q != 0) {

					r *= 16;

					switch (q) {

						case 'a': case 'A': r += 10; break;
						case 'b': case 'B': r += 11; break;
						case 'c': case 'C': r += 12; break;
						case 'd': case 'D': r += 13; break;
						case 'e': case 'E': r += 14; break;
						case 'f': case 'F': r += 15; break;
						default: r += q - '0'; break;
					}
				}

				result += static_cast <char>(r);
				break;
			}
			default:

				result += c;
				++it;
				break;
		}
	}

	return result;
}


} // utility
} // vmime