package org.bouncycastle.util.encoders;
import java.io.IOException;
import java.io.OutputStream;
public class Base64
{
private static final byte[] encodingTable =
{
(byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
(byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
(byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
(byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
(byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
(byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
(byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
(byte)'v',
(byte)'w', (byte)'x', (byte)'y', (byte)'z',
(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6',
(byte)'7', (byte)'8', (byte)'9',
(byte)'+', (byte)'/'
};
/**
* encode the input data producong a base 64 encoded byte array.
*
* @return a byte array containing the base 64 encoded data.
*/
public static byte[] encode(
byte[] 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;
}
/*
* set up the decoding table.
*/
private static final byte[] decodingTable;
static
{
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;
}
/**
* decode the base 64 encoded input data.
*
* @return a byte array representing the decoded data.
*/
public static byte[] decode(
byte[] data)
{
// 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;
}
/**
* decode the base 64 encoded String data.
*
* @return a byte array representing the decoded data.
*/
public static byte[] decode(
String 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;
}
/**
* decode the base 64 encoded String data writing it to the given output stream
*
* @return the number of bytes produced.
*/
public static int decode(
String data,
OutputStream out)
throws IOException
{
// 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;
}
}
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