/*
* 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 other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
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);
}
@Override
public long getObjectCount() {
return objectCnt;
}
@Override
public long getOffset64Count() {
long n64 = 0;
for (final MutableEntry e : this) {
if (e.getOffset() >= Integer.MAX_VALUE)
n64++;
}
return n64;
}
private int findLevelOne(final 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(final long nthPosition, final int levelOne) {
final long base = levelOne > 0 ? idxHeader[levelOne - 1] : 0;
return (int) (nthPosition - base);
}
@Override
public ObjectId getObjectId(final 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);
}
@Override
public long findOffset(final 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;
}
@Override
public long findCRC32(AnyObjectId objId) {
throw new UnsupportedOperationException();
}
@Override
public boolean hasCRC32Support() {
return false;
}
@Override
public Iterator<MutableEntry> iterator() {
return new IndexV1Iterator();
}
@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() {
protected void ensureId() {
idBuffer.fromRaw(idxdata[levelOne], levelTwo
- Constants.OBJECT_ID_LENGTH);
}
};
}
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();
}
}
}