// util/base64.h

/*    Copyright 2009 10gen Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    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 Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects
 *    for all of the code used other than as permitted herein. If you modify
 *    file(s) with this exception, you may extend this exception to your
 *    version of the file(s), but you are not obligated to do so. If you do not
 *    wish to do so, delete this exception statement from your version. If you
 *    delete this exception statement from all source files in the program,
 *    then also delete it in the license file.
 */

#pragma once

#include <boost/scoped_array.hpp>

#include "mongo/util/assert_util.h"

namespace mongo {
    namespace base64 {

        class Alphabet {
        public:
            Alphabet()
                : encode((unsigned char*)
                         "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                         "abcdefghijklmnopqrstuvwxyz"
                         "0123456789"
                         "+/")
                , decode(new unsigned char[257]) {
                memset( decode.get() , 0 , 256 );
                for ( int i=0; i<64; i++ ) {
                    decode[ encode[i] ] = i;
                }

                test();
            }
            void test() {
                verify( strlen( (char*)encode ) == 64 );
                for ( int i=0; i<26; i++ )
                    verify( encode[i] == toupper( encode[i+26] ) );
            }

            char e( int x ) {
                return encode[x&0x3f];
            }

        private:
            const unsigned char * encode;
        public:
            boost::scoped_array<unsigned char> decode;
        };

        extern Alphabet alphabet;


        void encode( std::stringstream& ss , const char * data , int size );
        std::string encode( const char * data , int size );
        std::string encode( const std::string& s );

        void decode( std::stringstream& ss , const std::string& s );
        std::string decode( const std::string& s );

        extern const char* chars;

        void testAlphabet();
    }
}