pjs/grendel/dog/mail/util/MessageInputStream.java

110 строки
2.8 KiB
Java

/*
* MessageInputStream.java
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
* License for the specific language governing rights and limitations
* under the License.
*
* The Original Code is Knife.
*
* The Initial Developer of the Original Code is dog.
* Portions created by dog are Copyright (C) 1998 dog <dog@dog.net.uk>. All Rights Reserved.
*
* Contributor(s): n/a.
*/
package dog.mail.util;
import java.io.*;
/**
* A utility class for feeding message contents to messages.
*
* @author dog@dog.net.uk
* @version 0.1
*/
public class MessageInputStream extends FilterInputStream {
/**
* The stream termination octet.
*/
public static final int END = 46;
/**
* The line termination octet.
*/
public static final int LF = 10;
boolean done = false;
int last = -1; // register for the last octet read
/**
* Constructs a message input stream connected to the specified pushback input stream.
*/
public MessageInputStream(PushbackInputStream in) {
super(in);
}
/**
* Reads the next byte of data from this message input stream.
* Returns -1 if the end of the message stream has been reached.
* @exception IOException if an I/O error occurs
*/
public int read() throws IOException {
if (done) return -1;
int ch = in.read();
if (ch==END && last==LF) {
int ch2 = in.read(); // look ahead for LF
if (ch2==LF) {
done = true;
return -1; // swallow the END and LF
} else
((PushbackInputStream)in).unread(ch2);
}
last = ch;
return ch;
}
/**
* Reads up to b.length bytes of data from this input stream into
* an array of bytes.
* Returns -1 if the end of the stream has been reached.
* @exception IOException if an I/O error occurs
*/
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
/**
* Reads up to len bytes of data from this input stream into an
* array of bytes, starting at the specified offset.
* Returns -1 if the end of the stream has been reached.
* @exception IOException if an I/O error occurs
*/
public int read(byte[] b, int off, int len) throws IOException {
if (done) return -1;
int l = in.read(b, off, len);
int i = indexOfEnd(b, off, l);
if (i>-1) {
((PushbackInputStream)in).unread(b, i+2, (l-(off+i+2)));
done = true;
return i-off;
}
return l;
}
// Discover the index of END in a byte array.
int indexOfEnd(byte[] b, int off, int len) {
for (int i=off+2; i<(off+len); i++)
if (b[i]==LF && b[i-1]==END && b[i-2]==LF)
return i-1;
return -1;
}
}