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// This code is derived from jcifs smb client library <jcifs at samba dot org>
// Ported by J. Arturo <webmaster at komodosoft dot net>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
using System;
using System.Text;
namespace SharpCifs.Util
{
public class Base64
{
private static readonly string Alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/// <summary>Base-64 encodes the supplied block of data.</summary>
/// <remarks>
/// Base-64 encodes the supplied block of data. Line wrapping is not
/// applied on output.
/// </remarks>
/// <param name="bytes">The block of data that is to be Base-64 encoded.</param>
/// <returns>A <code>String</code> containing the encoded data.</returns>
public static string Encode(byte[] bytes)
{
int length = bytes.Length;
if (length == 0)
{
return string.Empty;
}
StringBuilder buffer = new StringBuilder((int)Math.Ceiling(length / 3d) * 4);
int remainder = length % 3;
length -= remainder;
int block;
int i = 0;
while (i < length)
{
block = ((bytes[i++] & unchecked(0xff)) << 16) | ((bytes[i++] & unchecked(
0xff)) << 8) | (bytes[i++] & unchecked(0xff));
buffer.Append(Alphabet[(int)(((uint)block) >> 18)]);
buffer.Append(Alphabet[((int)(((uint)block) >> 12)) & unchecked(0x3f)]);
buffer.Append(Alphabet[((int)(((uint)block) >> 6)) & unchecked(0x3f)]);
buffer.Append(Alphabet[block & unchecked(0x3f)]);
}
if (remainder == 0)
{
return buffer.ToString();
}
if (remainder == 1)
{
block = (bytes[i] & unchecked(0xff)) << 4;
buffer.Append(Alphabet[(int)(((uint)block) >> 6)]);
buffer.Append(Alphabet[block & unchecked(0x3f)]);
buffer.Append("==");
return buffer.ToString();
}
block = (((bytes[i++] & unchecked(0xff)) << 8) | ((bytes[i]) & unchecked(0xff))) << 2;
buffer.Append(Alphabet[(int)(((uint)block) >> 12)]);
buffer.Append(Alphabet[((int)(((uint)block) >> 6)) & unchecked(0x3f)]);
buffer.Append(Alphabet[block & unchecked(0x3f)]);
buffer.Append("=");
return buffer.ToString();
}
/// <summary>Decodes the supplied Base-64 encoded string.</summary>
/// <remarks>Decodes the supplied Base-64 encoded string.</remarks>
/// <param name="string">The Base-64 encoded string that is to be decoded.</param>
/// <returns>A <code>byte[]</code> containing the decoded data block.</returns>
public static byte[] Decode(string @string)
{
int length = @string.Length;
if (length == 0)
{
return new byte[0];
}
int pad = (@string[length - 2] == '=') ? 2 : (@string[length - 1] == '=') ? 1 : 0;
int size = length * 3 / 4 - pad;
byte[] buffer = new byte[size];
int block;
int i = 0;
int index = 0;
while (i < length)
{
block = (Alphabet.IndexOf(@string[i++]) & unchecked(0xff)) << 18 | (Alphabet
.IndexOf(@string[i++]) & unchecked(0xff)) << 12 | (Alphabet.IndexOf(@string
[i++]) & unchecked(0xff)) << 6 | (Alphabet.IndexOf(@string[i++]) & unchecked(
0xff));
buffer[index++] = unchecked((byte)((int)(((uint)block) >> 16)));
if (index < size)
{
buffer[index++] = unchecked((byte)(((int)(((uint)block) >> 8)) & unchecked(0xff)));
}
if (index < size)
{
buffer[index++] = unchecked((byte)(block & unchecked(0xff)));
}
}
return buffer;
}
}
}
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