/**************************************************************
 * 
 * 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 <stdio.h>
#include <string.h>
#include "base64.h"

static const char base64_tab[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

extern "C" size_t base64_encode( FILE *fin, FILE *fout )
{
	size_t nBytesRead = 0;
	size_t nLineLength = 0;
	size_t nBytesWritten = 0;

	size_t nBytes = 0;

	do
	{
		unsigned char in_buffer[3];

		memset( in_buffer, 0, sizeof(in_buffer) );
		nBytes = fread( in_buffer, 1, sizeof(in_buffer), fin );
		nBytesRead += nBytes;

		if ( nBytes )
		{
			unsigned long value = 
				((unsigned long)in_buffer[0]) << 16 |
				((unsigned long)in_buffer[1]) << 8 |
				((unsigned long)in_buffer[2]) << 0;

			unsigned char out_buffer[4];

			memset( out_buffer, '=', sizeof(out_buffer) );

			out_buffer[0] = base64_tab[(value >> 18) & 0x3F];
			out_buffer[1] = base64_tab[(value >> 12) & 0x3F];

			if ( nBytes > 1 )
			{
				out_buffer[2] = base64_tab[(value >> 6) & 0x3F];
				if ( nBytes > 2 )
					out_buffer[3] = base64_tab[(value >> 0) & 0x3F];
			}

			if ( nLineLength >= 76 )
			{
				fputs( "\n", fout );
				nLineLength = 0;
			}

			nBytesWritten += fwrite( out_buffer, 1, sizeof(out_buffer), fout );
			nLineLength += sizeof(out_buffer);
		}
	} while ( nBytes );

	return nBytesWritten;
}