franta-hg@115: /*
franta-hg@115:  *   SONEWS News Server
franta-hg@115:  *   see AUTHORS for the list of contributors
franta-hg@115:  *
franta-hg@115:  *   This program is free software: you can redistribute it and/or modify
franta-hg@115:  *   it under the terms of the GNU General Public License as published by
franta-hg@115:  *   the Free Software Foundation, either version 3 of the License, or
franta-hg@115:  *   (at your option) any later version.
franta-hg@115:  *
franta-hg@115:  *   This program is distributed in the hope that it will be useful,
franta-hg@115:  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
franta-hg@115:  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
franta-hg@115:  *   GNU General Public License for more details.
franta-hg@115:  *
franta-hg@115:  *   You should have received a copy of the GNU General Public License
franta-hg@115:  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
franta-hg@115:  */
franta-hg@115: package org.sonews.util.io;
franta-hg@115: 
franta-hg@115: import java.io.FilterInputStream;
franta-hg@115: import java.io.IOException;
franta-hg@115: import java.io.InputStream;
franta-hg@115: 
franta-hg@115: /**
franta-hg@115:  * Filter input stream for reading from SMTP (or NNTP or similar) socket
franta-hg@115:  * where lines containing single dot have special meaning – end of message.
franta-hg@115:  * 
franta-hg@115:  * @author František Kučera (frantovo.cz)
franta-hg@115:  */
franta-hg@115: public class SMTPInputStream extends FilterInputStream {
franta-hg@115: 
franta-hg@115: 	public static final int CR = 0x0d;
franta-hg@115: 	public static final int LF = 0x0a;
franta-hg@115: 	public static final int DOT = 0x2e;
franta-hg@115: 	protected int last;
franta-hg@115: 
franta-hg@115: 	public SMTPInputStream(InputStream in) {
franta-hg@115: 		super(in);
franta-hg@115: 	}
franta-hg@115: 
franta-hg@115: 	/**
franta-hg@115: 	 * @return one byte as expected 
franta-hg@115: 	 * or -2 if there was line with single dot (which means end of message)
franta-hg@115: 	 * @throws IOException 
franta-hg@115: 	 */
franta-hg@115: 	@Override
franta-hg@115: 	public int read() throws IOException {
franta-hg@115: 		// read current character
franta-hg@115: 		int ch = super.read();
franta-hg@115: 
franta-hg@115: 		if (ch == DOT) {
franta-hg@115: 			if (last == LF) {
franta-hg@115: 				int next = super.read();
franta-hg@115: 
franta-hg@115: 				if (next == CR || next == LF) { // There should be CRLF, but we may accept also just LF or CR with missing LF. Or should we be more strict?
franta-hg@115: 					// <CRLF>.<CRLF> → end of current message
franta-hg@115: 					ch = -2;
franta-hg@115: 				} else {
franta-hg@115: 					// <CRLF>.… → eat one dot and return next character
franta-hg@115: 					ch = next;
franta-hg@115: 				}
franta-hg@115: 			}
franta-hg@115: 		}
franta-hg@115: 
franta-hg@115: 		last = ch;
franta-hg@115: 		return ch;
franta-hg@115: 	}
franta-hg@115: 
franta-hg@115: 	/**
franta-hg@115: 	 * @param buffer
franta-hg@115: 	 * @param offset
franta-hg@115: 	 * @param length
franta-hg@115: 	 * @return See {@link FilterInputStream#read(byte[], int, int)} or -2 (then see {@link #read(byte[])})
franta-hg@115: 	 * @throws IOException 
franta-hg@115: 	 */
franta-hg@115: 	@Override
franta-hg@115: 	public int read(byte[] buffer, int offset, int length) throws IOException {
franta-hg@115: 		if (buffer == null) {
franta-hg@115: 			throw new NullPointerException("Byte array should not be null.");
franta-hg@115: 		} else if ((offset < 0) || (offset > buffer.length) || (length < 0) || ((offset + length) > buffer.length) || ((offset + length) < 0)) {
franta-hg@115: 			throw new IndexOutOfBoundsException("Invalid offset or length.");
franta-hg@115: 		} else if (length == 0) {
franta-hg@115: 			return 0;
franta-hg@115: 		}
franta-hg@115: 
franta-hg@115: 		int ch = read();
franta-hg@115: 
franta-hg@115: 		if (ch == -1 || ch == -2) {
franta-hg@115: 			return ch;
franta-hg@115: 		}
franta-hg@115: 
franta-hg@115: 		buffer[offset] = (byte) ch;
franta-hg@115: 
franta-hg@115: 		int readCounter = 1;
franta-hg@115: 
franta-hg@115: 		for (; readCounter < length; readCounter++) {
franta-hg@115: 			ch = read();
franta-hg@115: 
franta-hg@115: 			if (ch == -1 || ch == -2) {
franta-hg@115: 				break;
franta-hg@115: 			}
franta-hg@115: 
franta-hg@115: 			if (buffer != null) {
franta-hg@115: 				buffer[offset + readCounter] = (byte) ch;
franta-hg@115: 			}
franta-hg@115: 		}
franta-hg@115: 
franta-hg@115: 		return readCounter;
franta-hg@115: 	}
franta-hg@115: }