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Base64.javaAPI DocAzureus 3.0.3.48706Thu Apr 19 13:42:58 BST 2007org.bouncycastle.util.encoders

Base64

public class Base64 extends Object

Fields Summary
private static final byte[]
encodingTable
private static final byte[]
decodingTable
Constructors Summary
Methods Summary
public static byte[]decode(byte[] data)
decode the base 64 encoded input data.

return
a byte array representing the decoded data.

		decodingTable = new byte[128];

		for (int i = 'A"; i <= 'Z"; i++)
		{
			decodingTable[i] = (byte)(i - 'A");
		}

		for (int i = 'a"; i <= 'z"; i++)
		{
			decodingTable[i] = (byte)(i - 'a" + 26);
		}

		for (int i = '0"; i <= '9"; i++)
		{
			decodingTable[i] = (byte)(i - '0" + 52);
		}

		decodingTable['+"] = 62;
		decodingTable['/"] = 63;
	
			// PARG - fix up for zero length encodes/decodes
		
		if ( data.length == 0 ){
			return( data );
		}
		
		byte[]	bytes;
		byte	b1, b2, b3, b4;

		if (data[data.length - 2] == '=")
		{
			bytes = new byte[(((data.length / 4) - 1) * 3) + 1];
		}
		else if (data[data.length - 1] == '=")
		{
			bytes = new byte[(((data.length / 4) - 1) * 3) + 2];
		}
		else
		{
			bytes = new byte[((data.length / 4) * 3)];
		}

		for (int i = 0, j = 0; i < data.length - 4; i += 4, j += 3)
		{
			b1 = decodingTable[data[i]];
			b2 = decodingTable[data[i + 1]];
			b3 = decodingTable[data[i + 2]];
			b4 = decodingTable[data[i + 3]];

			bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
			bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
			bytes[j + 2] = (byte)((b3 << 6) | b4);
		}

		if (data[data.length - 2] == '=")
		{
			b1 = decodingTable[data[data.length - 4]];
			b2 = decodingTable[data[data.length - 3]];

			bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
		}
		else if (data[data.length - 1] == '=")
		{
			b1 = decodingTable[data[data.length - 4]];
			b2 = decodingTable[data[data.length - 3]];
			b3 = decodingTable[data[data.length - 2]];

			bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
			bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
		}
		else
		{
			b1 = decodingTable[data[data.length - 4]];
			b2 = decodingTable[data[data.length - 3]];
			b3 = decodingTable[data[data.length - 2]];
			b4 = decodingTable[data[data.length - 1]];

			bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
			bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
			bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);
		}

		return bytes;
public static byte[]decode(java.lang.String data)
decode the base 64 encoded String data.

return
a byte array representing the decoded data.

			// PARG - fix up for zero length encodes/decodes
		
		if ( data.length() == 0 ){
			
			return( new byte[0] );
		}
		
		byte[]	bytes;
		byte	b1, b2, b3, b4;

		if (data.charAt(data.length() - 2) == '=")
		{
			bytes = new byte[(((data.length() / 4) - 1) * 3) + 1];
		}
		else if (data.charAt(data.length() - 1) == '=")
		{
			bytes = new byte[(((data.length() / 4) - 1) * 3) + 2];
		}
		else
		{
			bytes = new byte[((data.length() / 4) * 3)];
		}

		for (int i = 0, j = 0; i < data.length() - 4; i += 4, j += 3)
		{
			b1 = decodingTable[data.charAt(i)];
			b2 = decodingTable[data.charAt(i + 1)];
			b3 = decodingTable[data.charAt(i + 2)];
			b4 = decodingTable[data.charAt(i + 3)];

			bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
			bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
			bytes[j + 2] = (byte)((b3 << 6) | b4);
		}

		if (data.charAt(data.length() - 2) == '=")
		{
			b1 = decodingTable[data.charAt(data.length() - 4)];
			b2 = decodingTable[data.charAt(data.length() - 3)];

			bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
		}
		else if (data.charAt(data.length() - 1) == '=")
		{
			b1 = decodingTable[data.charAt(data.length() - 4)];
			b2 = decodingTable[data.charAt(data.length() - 3)];
			b3 = decodingTable[data.charAt(data.length() - 2)];

			bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
			bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
		}
		else
		{
			b1 = decodingTable[data.charAt(data.length() - 4)];
			b2 = decodingTable[data.charAt(data.length() - 3)];
			b3 = decodingTable[data.charAt(data.length() - 2)];
			b4 = decodingTable[data.charAt(data.length() - 1)];

			bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
			bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
			bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);
		}

		return bytes;
public static intdecode(java.lang.String data, java.io.OutputStream out)
decode the base 64 encoded String data writing it to the given output stream

return
the number of bytes produced.

			// PARG
		if ( data.length()== 0 ){
			
			return( 0 );
		}
		
		byte	b1, b2, b3, b4;
		int		length;

		if (data.charAt(data.length() - 2) == '=")
		{
			length = (((data.length() / 4) - 1) * 3) + 1;
		}
		else if (data.charAt(data.length() - 1) == '=")
		{
			length = (((data.length() / 4) - 1) * 3) + 2;
		}
		else
		{
			length = ((data.length() / 4) * 3);
		}
		
		for (int i = 0, j = 0; i < data.length() - 4; i += 4, j += 3)
		{
			b1 = decodingTable[data.charAt(i)];
			b2 = decodingTable[data.charAt(i + 1)];
			b3 = decodingTable[data.charAt(i + 2)];
			b4 = decodingTable[data.charAt(i + 3)];

			out.write((b1 << 2) | (b2 >> 4));
			out.write((b2 << 4) | (b3 >> 2));
			out.write((b3 << 6) | b4);
		}

		if (data.charAt(data.length() - 2) == '=")
		{
			b1 = decodingTable[data.charAt(data.length() - 4)];
			b2 = decodingTable[data.charAt(data.length() - 3)];

			out.write((b1 << 2) | (b2 >> 4));
		}
		else if (data.charAt(data.length() - 1) == '=")
		{
			b1 = decodingTable[data.charAt(data.length() - 4)];
			b2 = decodingTable[data.charAt(data.length() - 3)];
			b3 = decodingTable[data.charAt(data.length() - 2)];

			out.write((b1 << 2) | (b2 >> 4));
			out.write((b2 << 4) | (b3 >> 2));
		}
		else
		{
			b1 = decodingTable[data.charAt(data.length() - 4)];
			b2 = decodingTable[data.charAt(data.length() - 3)];
			b3 = decodingTable[data.charAt(data.length() - 2)];
			b4 = decodingTable[data.charAt(data.length() - 1)];

			out.write((b1 << 2) | (b2 >> 4));
			out.write((b2 << 4) | (b3 >> 2));
			out.write((b3 << 6) | b4);
		}

		return length;
public static byte[]encode(byte[] data)
encode the input data producong a base 64 encoded byte array.

return
a byte array containing the base 64 encoded data.


	                     	 
	   
			
	
		byte[]	bytes;
		
		int modulus = data.length % 3;
		if (modulus == 0)
		{
			bytes = new byte[4 * data.length / 3];
		}
		else
		{
			bytes = new byte[4 * ((data.length / 3) + 1)];
		}

        int dataLength = (data.length - modulus);
		int a1, a2, a3;
		for (int i = 0, j = 0; i < dataLength; i += 3, j += 4)
		{
			a1 = data[i] & 0xff;
			a2 = data[i + 1] & 0xff;
			a3 = data[i + 2] & 0xff;

			bytes[j] = encodingTable[(a1 >>> 2) & 0x3f];
			bytes[j + 1] = encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3f];
			bytes[j + 2] = encodingTable[((a2 << 2) | (a3 >>> 6)) & 0x3f];
			bytes[j + 3] = encodingTable[a3 & 0x3f];
		}

		/*
		 * process the tail end.
		 */
		int	b1, b2, b3;
		int	d1, d2;

		switch (modulus)
		{
		case 0:		/* nothing left to do */
			break;
		case 1:
			d1 = data[data.length - 1] & 0xff;
			b1 = (d1 >>> 2) & 0x3f;
			b2 = (d1 << 4) & 0x3f;

			bytes[bytes.length - 4] = encodingTable[b1];
			bytes[bytes.length - 3] = encodingTable[b2];
			bytes[bytes.length - 2] = (byte)'=";
			bytes[bytes.length - 1] = (byte)'=";
			break;
		case 2:
			d1 = data[data.length - 2] & 0xff;
			d2 = data[data.length - 1] & 0xff;

			b1 = (d1 >>> 2) & 0x3f;
			b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;
			b3 = (d2 << 2) & 0x3f;

			bytes[bytes.length - 4] = encodingTable[b1];
			bytes[bytes.length - 3] = encodingTable[b2];
			bytes[bytes.length - 2] = encodingTable[b3];
			bytes[bytes.length - 1] = (byte)'=";
			break;
		}

		return bytes;