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The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar
contains APIs for JDK 1.5 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one
provided with the Bouncy Castle Cryptography APIs.
package org.bouncycastle.util.encoders;
import java.io.IOException;
import java.io.OutputStream;
/**
* A streaming Base64 encoder.
*/
public class Base64Encoder
implements Encoder
{
protected 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)'/'
};
protected byte padding = (byte)'=';
/*
* set up the decoding table.
*/
protected final byte[] decodingTable = new byte[128];
protected void initialiseDecodingTable()
{
for (int i = 0; i < decodingTable.length; i++)
{
decodingTable[i] = (byte)0xff;
}
for (int i = 0; i < encodingTable.length; i++)
{
decodingTable[encodingTable[i]] = (byte)i;
}
}
public Base64Encoder()
{
initialiseDecodingTable();
}
public int encode(byte[] inBuf, int inOff, int inLen, byte[] outBuf, int outOff) throws IOException
{
int inPos = inOff;
int inEnd = inOff + inLen - 2;
int outPos = outOff;
while (inPos < inEnd)
{
int a1 = inBuf[inPos++];
int a2 = inBuf[inPos++] & 0xFF;
int a3 = inBuf[inPos++] & 0xFF;
outBuf[outPos++] = encodingTable[(a1 >>> 2) & 0x3F];
outBuf[outPos++] = encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3F];
outBuf[outPos++] = encodingTable[((a2 << 2) | (a3 >>> 6)) & 0x3F];
outBuf[outPos++] = encodingTable[a3 & 0x3F];
}
switch (inLen - (inPos - inOff))
{
case 1:
{
int a1 = inBuf[inPos++] & 0xFF;
outBuf[outPos++] = encodingTable[(a1 >>> 2) & 0x3F];
outBuf[outPos++] = encodingTable[(a1 << 4) & 0x3F];
outBuf[outPos++] = padding;
outBuf[outPos++] = padding;
break;
}
case 2:
{
int a1 = inBuf[inPos++] & 0xFF;
int a2 = inBuf[inPos++] & 0xFF;
outBuf[outPos++] = encodingTable[(a1 >>> 2) & 0x3F];
outBuf[outPos++] = encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3F];
outBuf[outPos++] = encodingTable[(a2 << 2) & 0x3F];
outBuf[outPos++] = padding;
break;
}
}
return outPos - outOff;
}
/**
* encode the input data producing a base 64 output stream.
*
* @return the number of bytes produced.
*/
public int encode(byte[] buf, int off, int len, OutputStream out)
throws IOException
{
byte[] tmp = new byte[72];
while (len > 0)
{
int inLen = Math.min(54, len);
int outLen = encode(buf, off, inLen, tmp, 0);
out.write(tmp, 0, outLen);
off += inLen;
len -= inLen;
}
return ((len + 2) / 3) * 4;
}
private boolean ignore(
char c)
{
return (c == '\n' || c =='\r' || c == '\t' || c == ' ');
}
/**
* decode the base 64 encoded byte data writing it to the given output stream,
* whitespace characters will be ignored.
*
* @return the number of bytes produced.
*/
public int decode(
byte[] data,
int off,
int length,
OutputStream out)
throws IOException
{
byte b1, b2, b3, b4;
byte[] outBuffer = new byte[54]; // S/MIME standard
int bufOff = 0;
int outLen = 0;
int end = off + length;
while (end > off)
{
if (!ignore((char)data[end - 1]))
{
break;
}
end--;
}
// empty data!
if (end == 0)
{
return 0;
}
int i = 0;
int finish = end;
while (finish > off && i != 4)
{
if (!ignore((char)data[finish - 1]))
{
i++;
}
finish--;
}
i = nextI(data, off, finish);
while (i < finish)
{
b1 = decodingTable[data[i++]];
i = nextI(data, i, finish);
b2 = decodingTable[data[i++]];
i = nextI(data, i, finish);
b3 = decodingTable[data[i++]];
i = nextI(data, i, finish);
b4 = decodingTable[data[i++]];
if ((b1 | b2 | b3 | b4) < 0)
{
throw new IOException("invalid characters encountered in base64 data");
}
outBuffer[bufOff++] = (byte)((b1 << 2) | (b2 >> 4));
outBuffer[bufOff++] = (byte)((b2 << 4) | (b3 >> 2));
outBuffer[bufOff++] = (byte)((b3 << 6) | b4);
if (bufOff == outBuffer.length)
{
out.write(outBuffer);
bufOff = 0;
}
outLen += 3;
i = nextI(data, i, finish);
}
if (bufOff > 0)
{
out.write(outBuffer, 0, bufOff);
}
int e0 = nextI(data, i, end);
int e1 = nextI(data, e0 + 1, end);
int e2 = nextI(data, e1 + 1, end);
int e3 = nextI(data, e2 + 1, end);
outLen += decodeLastBlock(out, (char)data[e0], (char)data[e1], (char)data[e2], (char)data[e3]);
return outLen;
}
private int nextI(byte[] data, int i, int finish)
{
while ((i < finish) && ignore((char)data[i]))
{
i++;
}
return i;
}
/**
* decode the base 64 encoded String data writing it to the given output stream,
* whitespace characters will be ignored.
*
* @return the number of bytes produced.
*/
public int decode(
String data,
OutputStream out)
throws IOException
{
byte b1, b2, b3, b4;
byte[] outBuffer = new byte[54]; // S/MIME standard
int bufOff = 0;
int length = 0;
int end = data.length();
while (end > 0)
{
if (!ignore(data.charAt(end - 1)))
{
break;
}
end--;
}
// empty data!
if (end == 0)
{
return 0;
}
int i = 0;
int finish = end;
while (finish > 0 && i != 4)
{
if (!ignore(data.charAt(finish - 1)))
{
i++;
}
finish--;
}
i = nextI(data, 0, finish);
while (i < finish)
{
b1 = decodingTable[data.charAt(i++)];
i = nextI(data, i, finish);
b2 = decodingTable[data.charAt(i++)];
i = nextI(data, i, finish);
b3 = decodingTable[data.charAt(i++)];
i = nextI(data, i, finish);
b4 = decodingTable[data.charAt(i++)];
if ((b1 | b2 | b3 | b4) < 0)
{
throw new IOException("invalid characters encountered in base64 data");
}
outBuffer[bufOff++] = (byte)((b1 << 2) | (b2 >> 4));
outBuffer[bufOff++] = (byte)((b2 << 4) | (b3 >> 2));
outBuffer[bufOff++] = (byte)((b3 << 6) | b4);
length += 3;
if (bufOff == outBuffer.length)
{
out.write(outBuffer);
bufOff = 0;
}
i = nextI(data, i, finish);
}
if (bufOff > 0)
{
out.write(outBuffer, 0, bufOff);
}
int e0 = nextI(data, i, end);
int e1 = nextI(data, e0 + 1, end);
int e2 = nextI(data, e1 + 1, end);
int e3 = nextI(data, e2 + 1, end);
length += decodeLastBlock(out, data.charAt(e0), data.charAt(e1), data.charAt(e2), data.charAt(e3));
return length;
}
private int decodeLastBlock(OutputStream out, char c1, char c2, char c3, char c4)
throws IOException
{
byte b1, b2, b3, b4;
if (c3 == padding)
{
if (c4 != padding)
{
throw new IOException("invalid characters encountered at end of base64 data");
}
b1 = decodingTable[c1];
b2 = decodingTable[c2];
if ((b1 | b2) < 0)
{
throw new IOException("invalid characters encountered at end of base64 data");
}
out.write((b1 << 2) | (b2 >> 4));
return 1;
}
else if (c4 == padding)
{
b1 = decodingTable[c1];
b2 = decodingTable[c2];
b3 = decodingTable[c3];
if ((b1 | b2 | b3) < 0)
{
throw new IOException("invalid characters encountered at end of base64 data");
}
out.write((b1 << 2) | (b2 >> 4));
out.write((b2 << 4) | (b3 >> 2));
return 2;
}
else
{
b1 = decodingTable[c1];
b2 = decodingTable[c2];
b3 = decodingTable[c3];
b4 = decodingTable[c4];
if ((b1 | b2 | b3 | b4) < 0)
{
throw new IOException("invalid characters encountered at end of base64 data");
}
out.write((b1 << 2) | (b2 >> 4));
out.write((b2 << 4) | (b3 >> 2));
out.write((b3 << 6) | b4);
return 3;
}
}
private int nextI(String data, int i, int finish)
{
while ((i < finish) && ignore(data.charAt(i)))
{
i++;
}
return i;
}
}