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- /*
- * Copyright (C) 2008-2009, Google Inc.
- * Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.com>
- * Copyright (C) 2007-2009, Robin Rosenberg <robin.rosenberg@dewire.com>
- * Copyright (C) 2006-2008, 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.InputStream;
- import java.util.Arrays;
- import java.util.Iterator;
- import java.util.NoSuchElementException;
- import java.util.Set;
-
- import org.eclipse.jgit.errors.CorruptObjectException;
- import org.eclipse.jgit.internal.JGitText;
- import org.eclipse.jgit.lib.AbbreviatedObjectId;
- import org.eclipse.jgit.lib.AnyObjectId;
- import org.eclipse.jgit.lib.Constants;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.util.IO;
- import org.eclipse.jgit.util.NB;
-
- class PackIndexV1 extends PackIndex {
- private static final int IDX_HDR_LEN = 256 * 4;
-
- private final long[] idxHeader;
-
- byte[][] idxdata;
-
- private long objectCnt;
-
- PackIndexV1(final InputStream fd, final byte[] hdr)
- throws CorruptObjectException, IOException {
- final byte[] fanoutTable = new byte[IDX_HDR_LEN];
- System.arraycopy(hdr, 0, fanoutTable, 0, hdr.length);
- IO.readFully(fd, fanoutTable, hdr.length, IDX_HDR_LEN - hdr.length);
-
- idxHeader = new long[256]; // really unsigned 32-bit...
- for (int k = 0; k < idxHeader.length; k++)
- idxHeader[k] = NB.decodeUInt32(fanoutTable, k * 4);
- idxdata = new byte[idxHeader.length][];
- for (int k = 0; k < idxHeader.length; k++) {
- int n;
- if (k == 0) {
- n = (int) (idxHeader[k]);
- } else {
- n = (int) (idxHeader[k] - idxHeader[k - 1]);
- }
- if (n > 0) {
- final long len = n * (Constants.OBJECT_ID_LENGTH + 4);
- if (len > Integer.MAX_VALUE - 8) // http://stackoverflow.com/a/8381338
- throw new IOException(JGitText.get().indexFileIsTooLargeForJgit);
-
- idxdata[k] = new byte[(int) len];
- IO.readFully(fd, idxdata[k], 0, idxdata[k].length);
- }
- }
- objectCnt = idxHeader[255];
-
- packChecksum = new byte[20];
- IO.readFully(fd, packChecksum, 0, packChecksum.length);
- }
-
- /** {@inheritDoc} */
- @Override
- public long getObjectCount() {
- return objectCnt;
- }
-
- /** {@inheritDoc} */
- @Override
- public long getOffset64Count() {
- long n64 = 0;
- for (MutableEntry e : this) {
- if (e.getOffset() >= Integer.MAX_VALUE)
- n64++;
- }
- return n64;
- }
-
- private int findLevelOne(long nthPosition) {
- int levelOne = Arrays.binarySearch(idxHeader, nthPosition + 1);
- if (levelOne >= 0) {
- // If we hit the bucket exactly the item is in the bucket, or
- // any bucket before it which has the same object count.
- //
- long base = idxHeader[levelOne];
- while (levelOne > 0 && base == idxHeader[levelOne - 1])
- levelOne--;
- } else {
- // The item is in the bucket we would insert it into.
- //
- levelOne = -(levelOne + 1);
- }
- return levelOne;
- }
-
- private int getLevelTwo(long nthPosition, int levelOne) {
- final long base = levelOne > 0 ? idxHeader[levelOne - 1] : 0;
- return (int) (nthPosition - base);
- }
-
- /** {@inheritDoc} */
- @Override
- public ObjectId getObjectId(long nthPosition) {
- final int levelOne = findLevelOne(nthPosition);
- final int p = getLevelTwo(nthPosition, levelOne);
- final int dataIdx = idOffset(p);
- return ObjectId.fromRaw(idxdata[levelOne], dataIdx);
- }
-
- @Override
- long getOffset(long nthPosition) {
- final int levelOne = findLevelOne(nthPosition);
- final int levelTwo = getLevelTwo(nthPosition, levelOne);
- final int p = (4 + Constants.OBJECT_ID_LENGTH) * levelTwo;
- return NB.decodeUInt32(idxdata[levelOne], p);
- }
-
- /** {@inheritDoc} */
- @Override
- public long findOffset(AnyObjectId objId) {
- final int levelOne = objId.getFirstByte();
- byte[] data = idxdata[levelOne];
- if (data == null)
- return -1;
- int high = data.length / (4 + Constants.OBJECT_ID_LENGTH);
- int low = 0;
- do {
- final int mid = (low + high) >>> 1;
- final int pos = idOffset(mid);
- final int cmp = objId.compareTo(data, pos);
- if (cmp < 0)
- high = mid;
- else if (cmp == 0) {
- int b0 = data[pos - 4] & 0xff;
- int b1 = data[pos - 3] & 0xff;
- int b2 = data[pos - 2] & 0xff;
- int b3 = data[pos - 1] & 0xff;
- return (((long) b0) << 24) | (b1 << 16) | (b2 << 8) | (b3);
- } else
- low = mid + 1;
- } while (low < high);
- return -1;
- }
-
- /** {@inheritDoc} */
- @Override
- public long findCRC32(AnyObjectId objId) {
- throw new UnsupportedOperationException();
- }
-
- /** {@inheritDoc} */
- @Override
- public boolean hasCRC32Support() {
- return false;
- }
-
- /** {@inheritDoc} */
- @Override
- public Iterator<MutableEntry> iterator() {
- return new IndexV1Iterator();
- }
-
- /** {@inheritDoc} */
- @Override
- public void resolve(Set<ObjectId> matches, AbbreviatedObjectId id,
- int matchLimit) throws IOException {
- byte[] data = idxdata[id.getFirstByte()];
- if (data == null)
- return;
- int max = data.length / (4 + Constants.OBJECT_ID_LENGTH);
- int high = max;
- int low = 0;
- do {
- int p = (low + high) >>> 1;
- final int cmp = id.prefixCompare(data, idOffset(p));
- if (cmp < 0)
- high = p;
- else if (cmp == 0) {
- // We may have landed in the middle of the matches. Move
- // backwards to the start of matches, then walk forwards.
- //
- while (0 < p && id.prefixCompare(data, idOffset(p - 1)) == 0)
- p--;
- for (; p < max && id.prefixCompare(data, idOffset(p)) == 0; p++) {
- matches.add(ObjectId.fromRaw(data, idOffset(p)));
- if (matches.size() > matchLimit)
- break;
- }
- return;
- } else
- low = p + 1;
- } while (low < high);
- }
-
- private static int idOffset(int mid) {
- return ((4 + Constants.OBJECT_ID_LENGTH) * mid) + 4;
- }
-
- private class IndexV1Iterator extends EntriesIterator {
- int levelOne;
-
- int levelTwo;
-
- @Override
- protected MutableEntry initEntry() {
- return new MutableEntry() {
- @Override
- protected void ensureId() {
- idBuffer.fromRaw(idxdata[levelOne], levelTwo
- - Constants.OBJECT_ID_LENGTH);
- }
- };
- }
-
- @Override
- public MutableEntry next() {
- for (; levelOne < idxdata.length; levelOne++) {
- if (idxdata[levelOne] == null)
- continue;
- if (levelTwo < idxdata[levelOne].length) {
- entry.offset = NB.decodeUInt32(idxdata[levelOne], levelTwo);
- levelTwo += Constants.OBJECT_ID_LENGTH + 4;
- returnedNumber++;
- return entry;
- }
- levelTwo = 0;
- }
- throw new NoSuchElementException();
- }
- }
- }
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