PackInputStream.java

/*
 * Copyright (C) 2010, Google Inc. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.internal.storage.file;

import java.io.IOException;
import java.io.InputStream;

class PackInputStream extends InputStream {
    private final WindowCursor wc;

    private final Pack pack;

    private long pos;

    PackInputStream(Pack pack, long pos, WindowCursor wc)
            throws IOException {
        this.pack = pack;
        this.pos = pos;
        this.wc = wc;

        // Pin the first window, to ensure the pack is open and valid.
        //
        wc.pin(pack, pos);
    }

    /** {@inheritDoc} */
    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        int n = wc.copy(pack, pos, b, off, len);
        pos += n;
        return n;
    }

    /** {@inheritDoc} */
    @Override
    public int read() throws IOException {
        byte[] buf = new byte[1];
        int n = read(buf, 0, 1);
        return n == 1 ? buf[0] & 0xff : -1;
    }

    /** {@inheritDoc} */
    @Override
    public void close() {
        wc.close();
    }
}