PackIndexWriterV2.java

/*
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> 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.OutputStream;

import org.eclipse.jgit.transport.PackedObjectInfo;
import org.eclipse.jgit.util.NB;

/**
 * Creates the version 2 pack table of contents files.
 *
 * @see PackIndexWriter
 * @see PackIndexV2
 */
class PackIndexWriterV2 extends PackIndexWriter {
    private static final int MAX_OFFSET_32 = 0x7fffffff;
    private static final int IS_OFFSET_64 = 0x80000000;

    PackIndexWriterV2(final OutputStream dst) {
        super(dst);
    }

    /** {@inheritDoc} */
    @Override
    protected void writeImpl() throws IOException {
        writeTOC(2);
        writeFanOutTable();
        writeObjectNames();
        writeCRCs();
        writeOffset32();
        writeOffset64();
        writeChecksumFooter();
    }

    private void writeObjectNames() throws IOException {
        for (PackedObjectInfo oe : entries)
            oe.copyRawTo(out);
    }

    private void writeCRCs() throws IOException {
        for (PackedObjectInfo oe : entries) {
            NB.encodeInt32(tmp, 0, oe.getCRC());
            out.write(tmp, 0, 4);
        }
    }

    private void writeOffset32() throws IOException {
        int o64 = 0;
        for (PackedObjectInfo oe : entries) {
            final long o = oe.getOffset();
            if (o <= MAX_OFFSET_32)
                NB.encodeInt32(tmp, 0, (int) o);
            else
                NB.encodeInt32(tmp, 0, IS_OFFSET_64 | o64++);
            out.write(tmp, 0, 4);
        }
    }

    private void writeOffset64() throws IOException {
        for (PackedObjectInfo oe : entries) {
            final long o = oe.getOffset();
            if (MAX_OFFSET_32 < o) {
                NB.encodeInt64(tmp, 0, o);
                out.write(tmp, 0, 8);
            }
        }
    }
}