/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "Base64.h"
#include <iostream>

static const std::string base64_chars =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";


static inline bool is_base64 ( unsigned char c )
{
    return ( isalnum ( c ) || ( c == '+' ) || ( c == '/' ) );
}

std::string base64_encode ( unsigned char const* bytes_to_encode, unsigned int in_len )
{
    std::string ret;
    int i = 0;
    int j = 0;
    unsigned char char_array_3[3];
    unsigned char char_array_4[4];

    while ( in_len-- )
    {
        char_array_3[i++] = * ( bytes_to_encode++ );

        if ( i == 3 )
        {
            char_array_4[0] = ( char_array_3[0] & 0xfc ) >> 2;
            char_array_4[1] = ( ( char_array_3[0] & 0x03 ) << 4 ) + ( ( char_array_3[1] & 0xf0 ) >> 4 );
            char_array_4[2] = ( ( char_array_3[1] & 0x0f ) << 2 ) + ( ( char_array_3[2] & 0xc0 ) >> 6 );
            char_array_4[3] = char_array_3[2] & 0x3f;

            for ( i = 0; ( i < 4 ); i++ )
            {
                ret += base64_chars[char_array_4[i]];
            }

            i = 0;
        }
    }

    if ( i )
    {
        for ( j = i; j < 3; j++ )
        {
            char_array_3[j] = '\0';
        }

        char_array_4[0] = ( char_array_3[0] & 0xfc ) >> 2;
        char_array_4[1] = ( ( char_array_3[0] & 0x03 ) << 4 ) + ( ( char_array_3[1] & 0xf0 ) >> 4 );
        char_array_4[2] = ( ( char_array_3[1] & 0x0f ) << 2 ) + ( ( char_array_3[2] & 0xc0 ) >> 6 );
        char_array_4[3] = char_array_3[2] & 0x3f;

        for ( j = 0; ( j < i + 1 ); j++ )
        {
            ret += base64_chars[char_array_4[j]];
        }

        while ( ( i++ < 3 ) )
        {
            ret += '=';
        }
    }

    return ret;
}

std::string base64_decode ( std::string const& encoded_string )
{
    int in_len = encoded_string . size ();
    int i = 0;
    int j = 0;
    int in_ = 0;
    unsigned char char_array_4[4], char_array_3[3];
    std::string ret;

    while ( in_len-- && ( encoded_string[in_] != '=' ) && is_base64 ( encoded_string[in_] ) )
    {
        char_array_4[i++] = encoded_string[in_];
        in_++;

        if ( i == 4 )
        {
            for ( i = 0; i < 4; i++ )
            {
                char_array_4[i] = base64_chars . find ( char_array_4[i] );
            }

            char_array_3[0] = ( char_array_4[0] << 2 ) + ( ( char_array_4[1] & 0x30 ) >> 4 );
            char_array_3[1] = ( ( char_array_4[1] & 0xf ) << 4 ) + ( ( char_array_4[2] & 0x3c ) >> 2 );
            char_array_3[2] = ( ( char_array_4[2] & 0x3 ) << 6 ) + char_array_4[3];

            for ( i = 0; ( i < 3 ); i++ )
            {
                ret += char_array_3[i];
            }

            i = 0;
        }
    }

    if ( i )
    {
        for ( j = i; j < 4; j++ )
        {
            char_array_4[j] = 0;
        }

        for ( j = 0; j < 4; j++ )
        {
            char_array_4[j] = base64_chars . find ( char_array_4[j] );
        }

        char_array_3[0] = ( char_array_4[0] << 2 ) + ( ( char_array_4[1] & 0x30 ) >> 4 );
        char_array_3[1] = ( ( char_array_4[1] & 0xf ) << 4 ) + ( ( char_array_4[2] & 0x3c ) >> 2 );
        char_array_3[2] = ( ( char_array_4[2] & 0x3 ) << 6 ) + char_array_4[3];

        for ( j = 0; ( j < i - 1 ); j++ )
        {
            ret += char_array_3[j];
        }
    }

    return ret;
}

