| /* |
| * Copyright (C) 2011, Google Inc. |
| * 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.storage.dht; |
| |
| import java.text.MessageFormat; |
| import java.util.List; |
| |
| import org.eclipse.jgit.generated.storage.dht.proto.GitStore.ChunkMeta; |
| import org.eclipse.jgit.generated.storage.dht.proto.GitStore.ChunkMeta.BaseChunk; |
| |
| class ChunkMetaUtil { |
| static BaseChunk getBaseChunk(ChunkKey chunkKey, ChunkMeta meta, |
| long position) throws DhtException { |
| // Chunks are sorted by ascending relative_start order. |
| // Thus for a pack sequence of: A B C, we have: |
| // |
| // -- C relative_start = 10,000 |
| // -- B relative_start = 20,000 |
| // -- A relative_start = 30,000 |
| // |
| // Indicating that chunk C starts 10,000 bytes before us, |
| // chunk B starts 20,000 bytes before us (and 10,000 before C), |
| // chunk A starts 30,000 bytes before us (and 10,000 before B), |
| // |
| // If position falls within: |
| // |
| // -- C (10k), then position is between 0..10,000 |
| // -- B (20k), then position is between 10,000 .. 20,000 |
| // -- A (30k), then position is between 20,000 .. 30,000 |
| |
| List<BaseChunk> baseChunks = meta.getBaseChunkList(); |
| int high = baseChunks.size(); |
| int low = 0; |
| while (low < high) { |
| final int mid = (low + high) >>> 1; |
| final BaseChunk base = baseChunks.get(mid); |
| |
| if (position > base.getRelativeStart()) { |
| low = mid + 1; |
| |
| } else if (mid == 0 || position == base.getRelativeStart()) { |
| return base; |
| |
| } else if (baseChunks.get(mid - 1).getRelativeStart() < position) { |
| return base; |
| |
| } else { |
| high = mid; |
| } |
| } |
| |
| throw new DhtException(MessageFormat.format( |
| DhtText.get().missingLongOffsetBase, chunkKey, |
| Long.valueOf(position))); |
| } |
| |
| static ChunkKey getNextFragment(ChunkMeta meta, ChunkKey chunkKey) { |
| int cnt = meta.getFragmentCount(); |
| for (int i = 0; i < cnt - 1; i++) { |
| ChunkKey key = ChunkKey.fromString(meta.getFragment(i)); |
| if (chunkKey.equals(key)) |
| return ChunkKey.fromString(meta.getFragment(i + 1)); |
| } |
| return null; |
| } |
| |
| private ChunkMetaUtil() { |
| // Static utilities only, do not create instances. |
| } |
| } |