int in the range 0
- * to 255. If no byte is available because the end of
- * the stream has been reached, the value -1 is returned.
- * This method blocks until input data is available, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return next byte of data, or -1 if the end of the
- * stream is reached.
- * @exception IOException if an I/O error occurs.
- * @see java.io.FilterInputStream#in
- */
- public int read() throws IOException {
- if (index >= bufsize) {
- decode(); // Fills up buffer
- if (bufsize == 0) // buffer is empty
- return -1;
- index = 0; // reset index into buffer
- }
- return buffer[index++] & 0xff; // Zero off the MSB
- }
-
- /**
- * Reads up to len decoded bytes of data from this input stream
- * into an array of bytes. This method blocks until some input is
- * available.
- *
- *
- * @param buf the buffer into which the data is read.
- * @param off the start offset of the data.
- * @param len the maximum number of bytes read.
- * @return the total number of bytes read into the buffer, or
- * -1 if there is no more data because the end of
- * the stream has been reached.
- * @exception IOException if an I/O error occurs.
- */
- public int read(byte[] buf, int off, int len) throws IOException {
- int i, c;
- for (i = 0; i < len; i++) {
- if ((c = read()) == -1) {
- if (i == 0) // At end of stream, so we should
- i = -1; // return -1 , NOT 0.
- break;
- }
- buf[off+i] = (byte)c;
- }
-
- return i;
- }
-
- /**
- * Tests if this input stream supports marks. Currently this class
- * does not support marks
- */
- public boolean markSupported() {
- return false; // Maybe later ..
- }
-
- /**
- * Returns the number of bytes that can be read from this input
- * stream without blocking. However, this figure is only
- * a close approximation in case the original encoded stream
- * contains embedded CRLFs; since the CRLFs are discarded, not decoded
- */
- public int available() throws IOException {
- // This is only an estimate, since in.available()
- // might include CRLFs too ..
- return ((in.available() * 3)/4 + (bufsize-index));
- }
-
- /**
- * This character array provides the character to value map
- * based on RFC1521.
- */
- private final static char pem_array[] = {
- 'A','B','C','D','E','F','G','H', // 0
- 'I','J','K','L','M','N','O','P', // 1
- 'Q','R','S','T','U','V','W','X', // 2
- 'Y','Z','a','b','c','d','e','f', // 3
- 'g','h','i','j','k','l','m','n', // 4
- 'o','p','q','r','s','t','u','v', // 5
- 'w','x','y','z','0','1','2','3', // 6
- '4','5','6','7','8','9','+','/' // 7
- };
-
- private final static byte pem_convert_array[] = new byte[256];
-
- static {
- for (int i = 0; i < 255; i++)
- pem_convert_array[i] = -1;
- for(int i = 0; i < pem_array.length; i++)
- pem_convert_array[pem_array[i]] = (byte) i;
- }
-
- /* The decoder algorithm */
- private byte[] decode_buffer = new byte[4];
- private void decode() throws IOException {
- bufsize = 0;
- /*
- * We need 4 valid base64 characters before we start decoding.
- * We skip anything that's not a valid base64 character (usually
- * just CRLF).
- */
- int got = 0;
- while (got < 4) {
- int i = in.read();
- if (i == -1) {
- if (got == 0)
- return; // EOF before any data is ok
- throw new IOException("Error in encoded stream, got " + got);
- }
- if (i >= 0 && i < 256 && i == '=' || pem_convert_array[i] != -1)
- decode_buffer[got++] = (byte)i;
- }
-
- byte a, b;
- a = pem_convert_array[decode_buffer[0] & 0xff];
- b = pem_convert_array[decode_buffer[1] & 0xff];
- // The first decoded byte
- buffer[bufsize++] = (byte)(((a << 2) & 0xfc) | ((b >>> 4) & 3));
-
- if (decode_buffer[2] == '=') // End of this BASE64 encoding
- return;
- a = b;
- b = pem_convert_array[decode_buffer[2] & 0xff];
- // The second decoded byte
- buffer[bufsize++] = (byte)(((a << 4) & 0xf0) | ((b >>> 2) & 0xf));
-
- if (decode_buffer[3] == '=') // End of this BASE64 encoding
- return;
- a = b;
- b = pem_convert_array[decode_buffer[3] & 0xff];
- // The third decoded byte
- buffer[bufsize++] = (byte)(((a << 6) & 0xc0) | (b & 0x3f));
- }
-
- /**
- * Base64 decode a byte array. No line breaks are allowed.
- * This method is suitable for short strings, such as those
- * in the IMAP AUTHENTICATE protocol, but not to decode the
- * entire content of a MIME part.
- *
- * NOTE: inbuf may only contain valid base64 characters.
- * Whitespace is not ignored.
- */
- public static byte[] decode(byte[] inbuf) {
- int size = (inbuf.length / 4) * 3;
- if (size == 0)
- return inbuf;
-
- if (inbuf[inbuf.length - 1] == '=') {
- size--;
- if (inbuf[inbuf.length - 2] == '=')
- size--;
- }
- byte[] outbuf = new byte[size];
-
- int inpos = 0, outpos = 0;
- size = inbuf.length;
- while (size > 0) {
- byte a, b;
- a = pem_convert_array[inbuf[inpos++] & 0xff];
- b = pem_convert_array[inbuf[inpos++] & 0xff];
- // The first decoded byte
- outbuf[outpos++] = (byte)(((a << 2) & 0xfc) | ((b >>> 4) & 3));
-
- if (inbuf[inpos] == '=') // End of this BASE64 encoding
- return outbuf;
- a = b;
- b = pem_convert_array[inbuf[inpos++] & 0xff];
- // The second decoded byte
- outbuf[outpos++] = (byte)(((a << 4) & 0xf0) | ((b >>> 2) & 0xf));
-
- if (inbuf[inpos] == '=') // End of this BASE64 encoding
- return outbuf;
- a = b;
- b = pem_convert_array[inbuf[inpos++] & 0xff];
- // The third decoded byte
- outbuf[outpos++] = (byte)(((a << 6) & 0xc0) | (b & 0x3f));
- size -= 4;
- }
- return outbuf;
- }
-
- /*** begin TEST program ***
- public static void main(String argv[]) throws Exception {
- FileInputStream infile = new FileInputStream(argv[0]);
- BASE64DecoderStream decoder = new BASE64DecoderStream(infile);
- int c;
-
- while ((c = decoder.read()) != -1)
- System.out.print((char)c);
- System.out.flush();
- }
- *** end TEST program ***/
-}