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- /*
- * The contents of this file are subject to the terms
- * of the Common Development and Distribution License
- * (the "License"). You may not use this file except
- * in compliance with the License.
- *
- * You can obtain a copy of the license at
- * glassfish/bootstrap/legal/CDDLv1.0.txt or
- * https://glassfish.dev.java.net/public/CDDLv1.0.html.
- * See the License for the specific language governing
- * permissions and limitations under the License.
- *
- * When distributing Covered Code, include this CDDL
- * HEADER in each file and include the License file at
- * glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
- * add the following below this CDDL HEADER, with the
- * fields enclosed by brackets "[]" replaced with your
- * own identifying information: Portions Copyright [yyyy]
- * [name of copyright owner]
- */
- /*
- * @(#)BASE64DecoderStream.java 1.15 06/09/25
- *
- * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
- */
- import java.io.*;
- /**
- * This class implements a BASE64 Decoder. It is implemented as
- * a FilterInputStream, so one can just wrap this class around
- * any input stream and read bytes from this filter. The decoding
- * is done as the bytes are read out.
- *
- * @author John Mani
- * @author Bill Shannon
- */
- public class BASE64DecoderStream extends FilterInputStream {
- // buffer of decoded bytes for single byte reads
- private byte[] buffer = new byte[3];
- private int bufsize = 0; // size of the cache
- private int index = 0; // index into the cache
- // buffer for almost 8K of typical 76 chars + CRLF lines,
- // used by getByte method. this buffer contains encoded bytes.
- private byte[] input_buffer = new byte[78*105];
- private int input_pos = 0;
- private int input_len = 0;;
- private boolean ignoreErrors = false;
- /**
- * Create a BASE64 decoder that decodes the specified input stream.
- * The System property <code>mail.mime.base64.ignoreerrors</code>
- * controls whether errors in the encoded data cause an exception
- * or are ignored. The default is false (errors cause exception).
- *
- * @param in the input stream
- */
- public BASE64DecoderStream(InputStream in) {
- super(in);
- try {
- String s = System.getProperty("mail.mime.base64.ignoreerrors");
- // default to false
- ignoreErrors = s != null && !s.equalsIgnoreCase("false");
- } catch (SecurityException sex) {
- // ignore it
- }
- }
- /**
- * Create a BASE64 decoder that decodes the specified input stream.
- *
- * @param in the input stream
- * @param ignoreErrors ignore errors in encoded data?
- */
- public BASE64DecoderStream(InputStream in, boolean ignoreErrors) {
- super(in);
- this.ignoreErrors = ignoreErrors;
- }
- /**
- * Read the next decoded byte from this input stream. The byte
- * is returned as an <code>int</code> in the range <code>0</code>
- * to <code>255</code>. If no byte is available because the end of
- * the stream has been reached, the value <code>-1</code> 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 <code>-1</code> 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) {
- bufsize = decode(buffer, 0, buffer.length);
- 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 <code>len</code> decoded bytes of data from this input stream
- * into an array of bytes. This method blocks until some input is
- * available.
- * <p>
- *
- * @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
- * <code>-1</code> 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 {
- // empty out single byte read buffer
- int off0 = off;
- while (index < bufsize && len > 0) {
- buf[off++] = buffer[index++];
- len--;
- }
- if (index >= bufsize)
- bufsize = index = 0;
- int bsize = (len / 3) * 3; // round down to multiple of 3 bytes
- if (bsize > 0) {
- int size = decode(buf, off, bsize);
- off += size;
- len -= size;
- if (size != bsize) { // hit EOF?
- if (off == off0) // haven't returned any data
- return -1;
- else // returned some data before hitting EOF
- return off - off0;
- }
- }
- // finish up with a partial read if necessary
- for (; len > 0; len--) {
- int c = read();
- if (c == -1) // EOF
- break;
- buf[off++] = (byte)c;
- }
- if (off == off0) // haven't returned any data
- return -1;
- else // returned some data before hitting EOF
- return off - off0;
- }
- /**
- * 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. Most of the complexity here is dealing
- * with error cases. Returns the number of bytes decoded, which
- * may be zero. Decoding is done by filling an int with 4 6-bit
- * values by shifting them in from the bottom and then extracting
- * 3 8-bit bytes from the int by shifting them out from the bottom.
- *
- * @param outbuf the buffer into which to put the decoded bytes
- * @param pos position in the buffer to start filling
- * @param len the number of bytes to fill
- * @return the number of bytes filled, always a multiple
- * of three, and may be zero
- * @exception IOException if the data is incorrectly formatted
- */
- private int decode(byte[] outbuf, int pos, int len) throws IOException {
- int pos0 = pos;
- while (len >= 3) {
- /*
- * 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;
- int val = 0;
- while (got < 4) {
- int i = getByte();
- if (i == -1 || i == -2) {
- boolean atEOF;
- if (i == -1) {
- if (got == 0)
- return pos - pos0;
- if (!ignoreErrors)
- throw new IOException("Error in encoded stream: " +
- "needed 4 valid base64 characters " +
- "but only got " + got + " before EOF" +
- recentChars());
- atEOF = true; // don't read any more
- } else { // i == -2
- // found a padding character, we're at EOF
- // XXX - should do something to make EOF "sticky"
- if (got < 2 && !ignoreErrors)
- throw new IOException("Error in encoded stream: " +
- "needed at least 2 valid base64 characters," +
- " but only got " + got +
- " before padding character (=)" +
- recentChars());
- // didn't get any characters before padding character?
- if (got == 0)
- return pos - pos0;
- atEOF = false; // need to keep reading
- }
- // pad partial result with zeroes
- // how many bytes will we produce on output?
- // (got always < 4, so size always < 3)
- int size = got - 1;
- if (size == 0)
- size = 1;
- // handle the one padding character we've seen
- got++;
- val <<= 6;
- while (got < 4) {
- if (!atEOF) {
- // consume the rest of the padding characters,
- // filling with zeroes
- i = getByte();
- if (i == -1) {
- if (!ignoreErrors)
- throw new IOException(
- "Error in encoded stream: " +
- "hit EOF while looking for " +
- "padding characters (=)" +
- recentChars());
- } else if (i != -2) {
- if (!ignoreErrors)
- throw new IOException(
- "Error in encoded stream: " +
- "found valid base64 character after " +
- "a padding character (=)" +
- recentChars());
- }
- }
- val <<= 6;
- got++;
- }
- // now pull out however many valid bytes we got
- val >>= 8; // always skip first one
- if (size == 2)
- outbuf[pos + 1] = (byte)(val & 0xff);
- val >>= 8;
- outbuf[pos] = (byte)(val & 0xff);
- // len -= size; // not needed, return below
- pos += size;
- return pos - pos0;
- } else {
- // got a valid byte
- val <<= 6;
- got++;
- val |= i;
- }
- }
- // read 4 valid characters, now extract 3 bytes
- outbuf[pos + 2] = (byte)(val & 0xff);
- val >>= 8;
- outbuf[pos + 1] = (byte)(val & 0xff);
- val >>= 8;
- outbuf[pos] = (byte)(val & 0xff);
- len -= 3;
- pos += 3;
- }
- return pos - pos0;
- }
- /**
- * Read the next valid byte from the input stream.
- * Buffer lots of data from underlying stream in input_buffer,
- * for efficiency.
- *
- * @return the next byte, -1 on EOF, or -2 if next byte is '='
- * (padding at end of encoded data)
- */
- private int getByte() throws IOException {
- int c;
- do {
- if (input_pos >= input_len) {
- try {
- input_len = in.read(input_buffer);
- } catch (EOFException ex) {
- return -1;
- }
- if (input_len <= 0)
- return -1;
- input_pos = 0;
- }
- // get the next byte in the buffer
- c = input_buffer[input_pos++] & 0xff;
- // is it a padding byte?
- if (c == '=')
- return -2;
- // no, convert it
- c = pem_convert_array[c];
- // loop until we get a legitimate byte
- } while (c == -1);
- return c;
- }
- /**
- * Return the most recent characters, for use in an error message.
- */
- private String recentChars() {
- // reach into the input buffer and extract up to 10
- // recent characters, to help in debugging.
- String errstr = "";
- int nc = input_pos > 10 ? 10 : input_pos;
- if (nc > 0) {
- errstr += ", the " + nc +
- " most recent characters were: \"";
- for (int k = input_pos - nc; k < input_pos; k++) {
- char c = (char)(input_buffer[k] & 0xff);
- switch (c) {
- case '\r': errstr += "\\r"; break;
- case '\n': errstr += "\\n"; break;
- case '\t': errstr += "\\t"; break;
- default:
- if (c >= ' ' && c < 0177)
- errstr += c;
- else
- errstr += ("\\" + (int)c);
- }
- }
- errstr += "\"";
- }
- return errstr;
- }
- /**
- * 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) {
- int val;
- int osize = 3;
- val = pem_convert_array[inbuf[inpos++] & 0xff];
- val <<= 6;
- val |= pem_convert_array[inbuf[inpos++] & 0xff];
- val <<= 6;
- if (inbuf[inpos] != '=') // End of this BASE64 encoding
- val |= pem_convert_array[inbuf[inpos++] & 0xff];
- else
- osize--;
- val <<= 6;
- if (inbuf[inpos] != '=') // End of this BASE64 encoding
- val |= pem_convert_array[inbuf[inpos++] & 0xff];
- else
- osize--;
- if (osize > 2)
- outbuf[outpos + 2] = (byte)(val & 0xff);
- val >>= 8;
- if (osize > 1)
- outbuf[outpos + 1] = (byte)(val & 0xff);
- val >>= 8;
- outbuf[outpos] = (byte)(val & 0xff);
- outpos += osize;
- 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 ***/
- }
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