aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: 
aoqi@0: /* FROM mail.jar */
aoqi@0: package com.sun.xml.internal.org.jvnet.mimepull;
aoqi@0: 
aoqi@0: import java.io.*;
aoqi@0: 
aoqi@0: /**
aoqi@0:  * This class is to support reading CRLF terminated lines that
aoqi@0:  * contain only US-ASCII characters from an input stream. Provides
aoqi@0:  * functionality that is similar to the deprecated
aoqi@0:  * <code>DataInputStream.readLine()</code>. Expected use is to read
aoqi@0:  * lines as String objects from a RFC822 stream.
aoqi@0:  *
aoqi@0:  * It is implemented as a FilterInputStream, so one can just wrap
aoqi@0:  * this class around any input stream and read bytes from this filter.
aoqi@0:  *
aoqi@0:  * @author John Mani
aoqi@0:  */
aoqi@0: 
aoqi@0: final class LineInputStream extends FilterInputStream {
aoqi@0: 
aoqi@0:     private char[] lineBuffer = null; // reusable byte buffer
aoqi@0:     private static int MAX_INCR = 1024*1024;    // 1MB
aoqi@0: 
aoqi@0:     public LineInputStream(InputStream in) {
aoqi@0:         super(in);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Read a line containing only ASCII characters from the input
aoqi@0:      * stream. A line is terminated by a CR or NL or CR-NL sequence.
aoqi@0:      * A common error is a CR-CR-NL sequence, which will also terminate
aoqi@0:      * a line.
aoqi@0:      * The line terminator is not returned as part of the returned
aoqi@0:      * String. Returns null if no data is available. <p>
aoqi@0:      *
aoqi@0:      * This class is similar to the deprecated
aoqi@0:      * <code>DataInputStream.readLine()</code>
aoqi@0:      */
aoqi@0:     public String readLine() throws IOException {
aoqi@0:         //InputStream in = this.in;
aoqi@0:         char[] buf = lineBuffer;
aoqi@0: 
aoqi@0:         if (buf == null) {
aoqi@0:             buf = lineBuffer = new char[128];
aoqi@0:         }
aoqi@0: 
aoqi@0:         int c1;
aoqi@0:         int room = buf.length;
aoqi@0:         int offset = 0;
aoqi@0: 
aoqi@0:         while ((c1 = in.read()) != -1) {
aoqi@0:             if (c1 == '\n') {
aoqi@0:                 break;
aoqi@0:             } else if (c1 == '\r') {
aoqi@0:                 // Got CR, is the next char NL ?
aoqi@0:                 boolean twoCRs = false;
aoqi@0:                 if (in.markSupported()) {
aoqi@0:                     in.mark(2);
aoqi@0:                 }
aoqi@0:                 int c2 = in.read();
aoqi@0:                 if (c2 == '\r') {               // discard extraneous CR
aoqi@0:                     twoCRs = true;
aoqi@0:                     c2 = in.read();
aoqi@0:                 }
aoqi@0:                 if (c2 != '\n') {
aoqi@0:                     /*
aoqi@0:                      * If the stream supports it (which we hope will always
aoqi@0:                      * be the case), reset to after the first CR.  Otherwise,
aoqi@0:                      * we wrap a PushbackInputStream around the stream so we
aoqi@0:                      * can unread the characters we don't need.  The only
aoqi@0:                      * problem with that is that the caller might stop
aoqi@0:                      * reading from this LineInputStream, throw it away,
aoqi@0:                      * and then start reading from the underlying stream.
aoqi@0:                      * If that happens, the pushed back characters will be
aoqi@0:                      * lost forever.
aoqi@0:                      */
aoqi@0:                     if (in.markSupported()) {
aoqi@0:                         in.reset();
aoqi@0:                     } else {
aoqi@0:                         if (!(in instanceof PushbackInputStream)) {
aoqi@0:                             in /*= this.in*/ = new PushbackInputStream(in, 2);
aoqi@0:                         }
aoqi@0:                         if (c2 != -1) {
aoqi@0:                             ((PushbackInputStream)in).unread(c2);
aoqi@0:                         }
aoqi@0:                         if (twoCRs) {
aoqi@0:                             ((PushbackInputStream)in).unread('\r');
aoqi@0:                         }
aoqi@0:                     }
aoqi@0:                 }
aoqi@0:                 break; // outa here.
aoqi@0:             }
aoqi@0: 
aoqi@0:             // Not CR, NL or CR-NL ...
aoqi@0:             // .. Insert the byte into our byte buffer
aoqi@0:             if (--room < 0) { // No room, need to grow.
aoqi@0:                 if (buf.length < MAX_INCR) {
aoqi@0:                     buf = new char[buf.length * 2];
aoqi@0:                 } else {
aoqi@0:                     buf = new char[buf.length + MAX_INCR];
aoqi@0:                 }
aoqi@0:                 room = buf.length - offset - 1;
aoqi@0:                 System.arraycopy(lineBuffer, 0, buf, 0, offset);
aoqi@0:                 lineBuffer = buf;
aoqi@0:             }
aoqi@0:             buf[offset++] = (char)c1;
aoqi@0:         }
aoqi@0: 
aoqi@0:         if ((c1 == -1) && (offset == 0)) {
aoqi@0:             return null;
aoqi@0:         }
aoqi@0: 
aoqi@0:         return String.copyValueOf(buf, 0, offset);
aoqi@0:     }
aoqi@0: }