/*
* Copyright(c) 2002 Center for E-Commerce Infrastructure Development, The
* University of Hong Kong (HKU). All Rights Reserved.
*
* This software is licensed under the Academic Free License Version 1.0
*
* Academic Free License
* Version 1.0
*
* This Academic Free License applies to any software and associated
* documentation (the "Software") whose owner (the "Licensor") has placed the
* statement "Licensed under the Academic Free License Version 1.0" immediately
* after the copyright notice that applies to the Software.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of the Software (1) to use, copy, modify, merge, publish, perform,
* distribute, sublicense, and/or sell copies of the Software, and to permit
* persons to whom the Software is furnished to do so, and (2) under patent
* claims owned or controlled by the Licensor that are embodied in the Software
* as furnished by the Licensor, to make, use, sell and offer for sale the
* Software and derivative works thereof, subject to the following conditions:
*
* - Redistributions of the Software in source code form must retain all
* copyright notices in the Software as furnished by the Licensor, this list
* of conditions, and the following disclaimers.
* - Redistributions of the Software in executable form must reproduce all
* copyright notices in the Software as furnished by the Licensor, this list
* of conditions, and the following disclaimers in the documentation and/or
* other materials provided with the distribution.
* - Neither the names of Licensor, nor the names of any contributors to the
* Software, nor any of their trademarks or service marks, may be used to
* endorse or promote products derived from this Software without express
* prior written permission of the Licensor.
*
* DISCLAIMERS: LICENSOR WARRANTS THAT THE COPYRIGHT IN AND TO THE SOFTWARE IS
* OWNED BY THE LICENSOR OR THAT THE SOFTWARE IS DISTRIBUTED BY LICENSOR UNDER
* A VALID CURRENT LICENSE. EXCEPT AS EXPRESSLY STATED IN THE IMMEDIATELY
* PRECEDING SENTENCE, THE SOFTWARE IS PROVIDED BY THE LICENSOR, CONTRIBUTORS
* AND COPYRIGHT OWNERS "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
* LICENSOR, CONTRIBUTORS OR COPYRIGHT OWNERS BE LIABLE FOR ANY CLAIM, DAMAGES
* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE.
*
* This license is Copyright (C) 2002 Lawrence E. Rosen. All rights reserved.
* Permission is hereby granted to copy and distribute this license without
* modification. This license may not be modified without the express written
* permission of its copyright owner.
*/
/*
* =====
*
* $Header: /home/cvsroot/ebxml-pkg/src/hk/hku/cecid/ebms/pkg/PartialInputStream.java,v 1.1 2005/07/28 09:36:24 dcmsze Exp $
*
* Code authored by:
*
* cyng [2002-07-29]
*
* Code reviewed by:
*
* username [YYYY-MM-DD]
*
* Remarks:
*
* =====
*/
package hk.hku.cecid.ebms.pkg;
import java.io.IOException;
import java.io.InputStream;
/**
* This is an implementation of <code>java.io.InputStream</code> that
* represents part of data read from an <code>InputStream</code>.
*
* @author cyng
* @version $Revision: 1.1 $
*/
class PartialInputStream extends InputStream {
private final InputStream in;
private final long length;
private long currentRead;
/**
* Constructor for the PartialInputStream object
*
* @param in the origninal input stream
* @param offset the offset the read data from the stream.
* @param length the length of the data to be read
* @exception IOException Description of the Exception
*/
PartialInputStream(InputStream in, long offset, long length)
throws IOException {
this.in = in;
this.length = length;
long skip = in.skip(offset);
long actualSkip = skip;
while (actualSkip >= 0 && skip < offset) {
actualSkip = in.skip(offset - skip);
if (actualSkip > 0) {
skip += actualSkip;
}
}
currentRead = 0;
}
/**
* close the stream
*
* @exception IOException thrown when IO error occur during closing
*/
public void close() throws IOException {
in.close();
}
/**
* read a byte from the stream
*
* @return the byte in int value from the stream.
* @exception IOException thrown when IO error occur during reading.
*/
public int read() throws IOException {
if (currentRead < length) {
int r = in.read();
if (r != -1) {
currentRead++;
}
return r;
} else {
return -1;
}
}
}