gecko-dev/grendel/storage/PartialFileInputStream.java
1998-09-09 00:52:38 +00:00

76 lines
2.0 KiB
Java

/* -*- Mode: java; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* 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 the Grendel mail/news client.
*
* The Initial Developer of the Original Code is Netscape Communications
* Corporation. Portions created by Netscape are Copyright (C) 1997
* Netscape Communications Corporation. All Rights Reserved.
*
* Created: Terry Weissman <terry@netscape.com>, 28 Aug 1997.
*/
package grendel.storage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.IOException;
/** Implements an input stream that comes from just a portion of a file. */
class PartialFileInputStream extends FileInputStream {
int remaining = 1 << 30;
public PartialFileInputStream(File f, int start, int length)
throws IOException, FileNotFoundException
{
super(f);
skip(start);
remaining = length;
}
public int read() throws IOException {
if (remaining <= 0) return -1;
remaining--;
return super.read();
}
public int read(byte b[]) throws IOException {
if (remaining <= 0) return -1;
int result = super.read(b);
if (result > 0) {
if (result > remaining) result = remaining;
remaining -= result;
}
return result;
}
public int read(byte b[], int off, int length) throws IOException {
if (remaining <= 0) return -1;
if (length > remaining) length = remaining;
int result = super.read(b, off, length);
if (result > 0) {
if (result > remaining) result = remaining;
remaining -= result;
}
return result;
}
}