BASE64 encoder implementation
/*
* Copyright World Wide Web Consortium, (Massachusetts Institute of Technology,
* Institut National de Recherche en Informatique et en Automatique, Keio University).
* All Rights Reserved. http://www.w3.org/Consortium/Legal/
*/
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
/**
* BASE64 encoder implementation.
* This object takes as parameter an input stream and an output stream. It
* encodes the input stream, using the BASE64 encoding rules, as defined
* in <a href="http://ds.internic.net/rfc/rfc1521.txt">MIME specification</a>
* and emit the resulting data to the output stream.
* @see org.w3c.tools.codec.Base64Decoder
*/
public class Base64Encoder
{
private static final int BUFFER_SIZE = 1024;
private static byte encoding[] =
{
(byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G', (byte) 'H', // 0-7
(byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P', // 8-15
(byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U', (byte) 'V', (byte) 'W', (byte) 'X', // 16-23
(byte) 'Y', (byte) 'Z', (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f', // 24-31
(byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k', (byte) 'l', (byte) 'm', (byte) 'n', // 32-39
(byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r', (byte) 's', (byte) 't', (byte) 'u', (byte) 'v', // 40-47
(byte) 'w', (byte) 'x', (byte) 'y', (byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3', // 48-55
(byte) '4', (byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9', (byte) '+', (byte) '/', // 56-63
(byte) '=' // 64
};
InputStream in = null;
OutputStream out = null;
boolean stringp = false;
private final int get1(byte buf[], int off)
{
return (buf[off] & 0xfc) >> 2;
}
private final int get2(byte buf[], int off)
{
return ((buf[off] & 0x3) << 4) | ((buf[off + 1] & 0xf0) >>> 4);
}
private final int get3(byte buf[], int off)
{
return ((buf[off + 1] & 0x0f) << 2) | ((buf[off + 2] & 0xc0) >>> 6);
}
private static final int get4(byte buf[], int off)
{
return buf[off + 2] & 0x3f;
}
/**
* Process the data: encode the input stream to the output stream.
* This method runs through the input stream, encoding it to the output
* stream.
* @exception IOException If we weren't able to access the input stream or
* the output stream.
*/
public void process() throws IOException
{
byte buffer[] = new byte[BUFFER_SIZE];
int got = -1;
int off = 0;
int count = 0;
while ((got = in.read(buffer, off, BUFFER_SIZE - off)) > 0)
{
if (got >= 3)
{
got += off;
off = 0;
while (off + 3 <= got)
{
int c1 = get1(buffer, off);
int c2 = get2(buffer, off);
int c3 = get3(buffer, off);
int c4 = get4(buffer, off);
switch (count)
{
case 73 :
out.write(encoding[c1]);
out.write(encoding[c2]);
out.write(encoding[c3]);
out.write('\n');
out.write(encoding[c4]);
count = 1;
break;
case 74 :
out.write(encoding[c1]);
out.write(encoding[c2]);
out.write('\n');
out.write(encoding[c3]);
out.write(encoding[c4]);
count = 2;
break;
case 75 :
out.write(encoding[c1]);
out.write('\n');
out.write(encoding[c2]);
out.write(encoding[c3]);
out.write(encoding[c4]);
count = 3;
break;
case 76 :
out.write('\n');
out.write(encoding[c1]);
out.write(encoding[c2]);
out.write(encoding[c3]);
out.write(encoding[c4]);
count = 4;
break;
default :
out.write(encoding[c1]);
out.write(encoding[c2]);
out.write(encoding[c3]);
out.write(encoding[c4]);
count += 4;
break;
}
off += 3;
}
// Copy remaining bytes to beginning of buffer:
for (int i = 0; i < 3; i++)
buffer[i] = (i < got - off) ? buffer[off + i] : ((byte) 0);
off = got - off;
}
else
{
// Total read amount is less then 3 bytes:
off += got;
}
}
// Manage the last bytes, from 0 to off:
switch (off)
{
case 1 :
out.write(encoding[get1(buffer, 0)]);
out.write(encoding[get2(buffer, 0)]);
out.write('=');
out.write('=');
break;
case 2 :
out.write(encoding[get1(buffer, 0)]);
out.write(encoding[get2(buffer, 0)]);
out.write(encoding[get3(buffer, 0)]);
out.write('=');
}
return;
}
/**
* Encode the content of this encoder, as a string.
* This methods encode the String content, that was provided at creation
* time, following the BASE64 rules, as specified in the rfc1521.
* @return A String, reprenting the encoded content of the input String.
*/
public String processString()
{
if (!stringp)
throw new RuntimeException(
this.getClass().getName()
+ "[processString]"
+ "invalid call (not a String)");
try
{
process();
}
catch (IOException e)
{
}
return ((ByteArrayOutputStream) out).toString();
}
/**
* Create a new Base64 encoder, to encode the given string.
* @param input The String to be encoded.
*/
public Base64Encoder(String input)
{
byte bytes[];
try
{
bytes = input.getBytes("ISO-8859-1");
}
catch (UnsupportedEncodingException ex)
{
throw new RuntimeException(
this.getClass().getName()
+ "[Constructor] Unable to convert"
+ "properly char to bytes");
}
this.stringp = true;
this.in = new ByteArrayInputStream(bytes);
this.out = new ByteArrayOutputStream();
}
/**
* Create a new Base64 encoder, encoding input to output.
* @param in The input stream to be encoded.
* @param out The output stream, to write encoded data to.
*/
public Base64Encoder(InputStream in, OutputStream out)
{
this.in = in;
this.out = out;
this.stringp = false;
}
/**
* Testing the encoder.
* Run with one argument, prints the encoded version of it.
*/
public static void main(String args[])
{
if (args.length != 1)
{
System.out.println("Base64Encoder <string>");
System.exit(0);
}
Base64Encoder b = new Base64Encoder(args[0]);
System.out.println("[" + b.processString() + "]");
// joe:eoj -> am9lOmVvag==
// 12345678:87654321 -> MTIzNDU2Nzg6ODc2NTQzMjE=
}
}
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