001: /*
002: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
003: *
004: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
005: *
006: * The contents of this file are subject to the terms of either the GNU
007: * General Public License Version 2 only ("GPL") or the Common Development
008: * and Distribution License("CDDL") (collectively, the "License"). You
009: * may not use this file except in compliance with the License. You can obtain
010: * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
011: * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
012: * language governing permissions and limitations under the License.
013: *
014: * When distributing the software, include this License Header Notice in each
015: * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
016: * Sun designates this particular file as subject to the "Classpath" exception
017: * as provided by Sun in the GPL Version 2 section of the License file that
018: * accompanied this code. If applicable, add the following below the License
019: * Header, with the fields enclosed by brackets [] replaced by your own
020: * identifying information: "Portions Copyrighted [year]
021: * [name of copyright owner]"
022: *
023: * Contributor(s):
024: *
025: * If you wish your version of this file to be governed by only the CDDL or
026: * only the GPL Version 2, indicate your decision by adding "[Contributor]
027: * elects to include this software in this distribution under the [CDDL or GPL
028: * Version 2] license." If you don't indicate a single choice of license, a
029: * recipient has the option to distribute your version of this file under
030: * either the CDDL, the GPL Version 2 or to extend the choice of license to
031: * its licensees as provided above. However, if you add GPL Version 2 code
032: * and therefore, elected the GPL Version 2 license, then the option applies
033: * only if the new code is made subject to such option by the copyright
034: * holder.
035: */
036:
037: /*
038: * @(#)QPDecoderStream.java 1.11 07/05/04
039: */
040:
041: package com.sun.mail.util;
042:
043: import java.io.*;
044:
045: /**
046: * This class implements a QP Decoder. It is implemented as
047: * a FilterInputStream, so one can just wrap this class around
048: * any input stream and read bytes from this filter. The decoding
049: * is done as the bytes are read out.
050: *
051: * @author John Mani
052: */
053:
054: public class QPDecoderStream extends FilterInputStream {
055: protected byte[] ba = new byte[2];
056: protected int spaces = 0;
057:
058: /**
059: * Create a Quoted Printable decoder that decodes the specified
060: * input stream.
061: * @param in the input stream
062: */
063: public QPDecoderStream(InputStream in) {
064: super (new PushbackInputStream(in, 2)); // pushback of size=2
065: }
066:
067: /**
068: * Read the next decoded byte from this input stream. The byte
069: * is returned as an <code>int</code> in the range <code>0</code>
070: * to <code>255</code>. If no byte is available because the end of
071: * the stream has been reached, the value <code>-1</code> is returned.
072: * This method blocks until input data is available, the end of the
073: * stream is detected, or an exception is thrown.
074: *
075: * @return the next byte of data, or <code>-1</code> if the end of the
076: * stream is reached.
077: * @exception IOException if an I/O error occurs.
078: */
079: public int read() throws IOException {
080: if (spaces > 0) {
081: // We have cached space characters, return one
082: spaces--;
083: return ' ';
084: }
085:
086: int c = in.read();
087:
088: if (c == ' ') {
089: // Got space, keep reading till we get a non-space char
090: while ((c = in.read()) == ' ')
091: spaces++;
092:
093: if (c == '\r' || c == '\n' || c == -1)
094: // If the non-space char is CR/LF/EOF, the spaces we got
095: // so far is junk introduced during transport. Junk 'em.
096: spaces = 0;
097: else {
098: // The non-space char is NOT CR/LF, the spaces are valid.
099: ((PushbackInputStream) in).unread(c);
100: c = ' ';
101: }
102: return c; // return either <SPACE> or <CR/LF>
103: } else if (c == '=') {
104: // QP Encoded atom. Decode the next two bytes
105: int a = in.read();
106:
107: if (a == '\n') {
108: /* Hmm ... not really confirming QP encoding, but lets
109: * allow this as a LF terminated encoded line .. and
110: * consider this a soft linebreak and recurse to fetch
111: * the next char.
112: */
113: return read();
114: } else if (a == '\r') {
115: // Expecting LF. This forms a soft linebreak to be ignored.
116: int b = in.read();
117: if (b != '\n')
118: /* Not really confirming QP encoding, but
119: * lets allow this as well.
120: */
121: ((PushbackInputStream) in).unread(b);
122: return read();
123: } else if (a == -1) {
124: // Not valid QP encoding, but we be nice and tolerant here !
125: return -1;
126: } else {
127: ba[0] = (byte) a;
128: ba[1] = (byte) in.read();
129: try {
130: return ASCIIUtility.parseInt(ba, 0, 2, 16);
131: } catch (NumberFormatException nex) {
132: /*
133: System.err.println(
134: "Illegal characters in QP encoded stream: " +
135: ASCIIUtility.toString(ba, 0, 2)
136: );
137: */
138:
139: ((PushbackInputStream) in).unread(ba);
140: return c;
141: }
142: }
143: }
144: return c;
145: }
146:
147: /**
148: * Reads up to <code>len</code> decoded bytes of data from this input stream
149: * into an array of bytes. This method blocks until some input is
150: * available.
151: * <p>
152: *
153: * @param buf the buffer into which the data is read.
154: * @param off the start offset of the data.
155: * @param len the maximum number of bytes read.
156: * @return the total number of bytes read into the buffer, or
157: * <code>-1</code> if there is no more data because the end of
158: * the stream has been reached.
159: * @exception IOException if an I/O error occurs.
160: */
161: public int read(byte[] buf, int off, int len) throws IOException {
162: int i, c;
163: for (i = 0; i < len; i++) {
164: if ((c = read()) == -1) {
165: if (i == 0) // At end of stream, so we should
166: i = -1; // return -1 , NOT 0.
167: break;
168: }
169: buf[off + i] = (byte) c;
170: }
171: return i;
172: }
173:
174: /**
175: * Tests if this input stream supports marks. Currently this class
176: * does not support marks
177: */
178: public boolean markSupported() {
179: return false;
180: }
181:
182: /**
183: * Returns the number of bytes that can be read from this input
184: * stream without blocking. The QP algorithm does not permit
185: * a priori knowledge of the number of bytes after decoding, so
186: * this method just invokes the <code>available</code> method
187: * of the original input stream.
188: */
189: public int available() throws IOException {
190: // This is bogus ! We don't really know how much
191: // bytes are available *after* decoding
192: return in.available();
193: }
194:
195: /**** begin TEST program
196: public static void main(String argv[]) throws Exception {
197: FileInputStream infile = new FileInputStream(argv[0]);
198: QPDecoderStream decoder = new QPDecoderStream(infile);
199: int c;
200:
201: while ((c = decoder.read()) != -1)
202: System.out.print((char)c);
203: System.out.println();
204: }
205: *** end TEST program ****/
206: }
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