using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace WMFConverter.Util
{
///
/// Base 64 encode
///
public class Base64
{
#region Local Variables
private static char[] ENCODE_DATA = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/'
};
#endregion
#region Public Methods
///
/// Encode byte array.
///
///
///
public static string Encode(byte[] data)
{
char[] buffer = null;
if (data.Length % 3 == 0)
buffer = new char[data.Length / 3 * 4];
else
buffer = new char[(data.Length / 3 + 1) * 4];
int buf = 0;
for (int i = 0; i < data.Length; i++)
{
switch (i % 3)
{
case 0 :
buffer[i / 3 * 4] = ENCODE_DATA[(data[i] & 0xFC) >> 2];
buf = (data[i] & 0x03) << 4;
if (i + 1 == data.Length)
{
buffer[i / 3 * 4 + 1] = ENCODE_DATA[buf];
buffer[i / 3 * 4 + 2] = '=';
buffer[i / 3 * 4 + 3] = '=';
}
break;
case 1 :
buf += (data[i] & 0xF0) >> 4;
buffer[i / 3 * 4 + 1] = ENCODE_DATA[buf];
buf = (data[i] & 0x0F) << 2;
if (i + 1 == data.Length)
{
buffer[i / 3 * 4 + 2] = ENCODE_DATA[buf];
buffer[i / 3 * 4 + 3] = '=';
}
break;
case 2 :
buf += (data[i] & 0xC0) >> 6;
buffer[i / 3 * 4 + 2] = ENCODE_DATA[buf];
buffer[i / 3 * 4 + 3] = ENCODE_DATA[data[i] & 0x3F];
break;
}
}
return new string(buffer);
}
#endregion
}
}