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/*
* Copyright (C) 2008 ScalAgent Distributed Technologies
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA.
*/
package fr.dyade.aaa.agent;
import java.io.IOException;
/**
* Class used to recv messages through a stream in a byte array.
*
* Be careful this InputStream is not synchronized.
*/
public abstract class ByteArrayMessageInputStream extends MessageInputStream {
/**
* Creates a ByteArrayMessageInputStream that uses
* buf as its buffer array.
*
* Be careful, the buffer array is not copied. The initial value of
* pos is 0 and the initial value of count
* is the length of buf.
*
* @param buf the input buffer.
*/
public ByteArrayMessageInputStream(byte[] buf) {
this(buf, 0, buf.length);
}
/**
* Creates ByteArrayMessageInputStream that uses
* buf as its buffer array.
*
* Be careful, the buffer array is not copied. The initial value of
* pos is offset and the initial value of
* count is the minimum of offset+length and
* buf.length.
*
* @param buf the input buffer.
* @param offset the offset in the buffer of the first byte to read.
* @param length the maximum number of bytes to read from the buffer.
*/
public ByteArrayMessageInputStream(byte[] buf, int offset, int length) {
this.buf = buf;
pos = offset;
count = Math.min(offset + length, buf.length);
}
/**
* Reads the next byte of data from the input stream. The value byte is
* returned as an int in the range 0 to
* 255. If no byte is available because the end of the stream
* has been reached, the value -1 is returned. This method
* blocks until input data is available, the end of the stream is detected,
* or an exception is thrown.
*
* @return the next byte of data, or -1 if the end of the
* stream is reached.
*/
public final int read() {
return (pos < count)?(buf[pos++] & 0xff):-1;
}
/**
* Reads up to len bytes of data from the input stream into
* an array of bytes. An attempt is made to read as many as
* len bytes, but a smaller number may be read.
* The number of bytes actually read is returned as an integer.
*
* This method blocks until input data is available, end of file is
* detected, or an exception is thrown.
*
* @param b the buffer into which the data is read.
* @param off the start offset in array b
* at which the data is written.
* @param len the maximum number of bytes to read.
* @return the total number of bytes read into the buffer, or
* -1 if there is no more data because the end of
* the stream has been reached.
* @exception NullPointerException If b is null.
* @exception IndexOutOfBoundsException If off is negative,
* len is negative, or len is greater than
* b.length - off
*/
public final int read(byte b[], int off, int len) throws IOException {
if (b == null)
throw new NullPointerException();
if (off < 0 || len < 0 || len > b.length - off)
throw new IndexOutOfBoundsException();
if (pos >= count)
return -1;
if (pos + len > count)
len = count - pos;
if (len <= 0) return 0;
System.arraycopy(buf, pos, b, off, len);
pos += len;
return len;
}
/**
* Reads length bytes of data from the input stream.
*/
protected final void readFully(int length) throws IOException {
// Data are fully available in the buffer.
}
}