Base64 Decoding

Decodes data encoded with MIME base64.

• C#
• VB.Net
• C
• C++
• PHP

									public static byte[] Base64Decoding(char[] data)
{
	int length, length2, length3;
	int blockCount;
	int paddingCount = 0;

	length = data.Length;
	blockCount = length / 4;
	length2 = blockCount * 3;

	for (int x = 0; x < 2; x++)
	{
		if (data[length - x - 1] == '=')
			paddingCount++;
	}

	byte[] buffer = new byte[length];
	byte[] buffer2 = new byte[length2];

	for (int x = 0; x < length; x++)
	{
		buffer[x] = CharToSixBit(data[x]);
	}

	byte b, b1, b2, b3;
	byte temp1, temp2, temp3, temp4;

	for (int x = 0; x < blockCount; x++)
	{
		temp1 = buffer[x * 4];
		temp2 = buffer[x * 4 + 1];
		temp3 = buffer[x * 4 + 2];
		temp4 = buffer[x * 4 + 3];

		b = (byte)(temp1 << 2);
		b1 = (byte)((temp2 & 48) >> 4);
		b1 += b;

		b = (byte)((temp2 & 15) << 4);
		b2 = (byte)((temp3 & 60) >> 2);
		b2 += b;

		b = (byte)((temp3 & 3) << 6);
		b3 = temp4;
		b3 += b;

		buffer2[x * 3] = b1;
		buffer2[x * 3 + 1] = b2;
		buffer2[x * 3 + 2] = b3;
	}

	length3 = length2 - paddingCount;
	byte[] result = new byte[length3];

	for (int x = 0; x < length3; x++)
	{
		result[x] = buffer2[x];
	}

	return result;
}

private static byte CharToSixBit(char c)
{
	char[] lookupTable = new char[64] {
		'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','+','/'
	};

	if (c == '=')
	{
		return 0;
	}
	else
	{
		for (int x = 0; x < 64; x++)
		{
			if (lookupTable[x] == c)
				return (byte)x;
		}

		return 0;
	}
}
								

Example

									string data = "amRmZ3NkaGZzZGZzZCA2NDQ1ZHNmc2Q3ZmcvKi8rYmZqc2RnZiUkXg==";
byte[] value = Base64Decoding(data.ToCharArray());
								

Output

									jdfgsdhfsdfsd 6445dsfsd7fg/*/+bfjsdgf%$^