| /* |
| * Copyright (C) 2012, 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.internal.storage.file; |
| |
| import java.util.Arrays; |
| |
| import com.googlecode.javaewah.EWAHCompressedBitmap; |
| |
| /** |
| * A random access BitSet to supports efficient conversions to |
| * EWAHCompressedBitmap. |
| */ |
| final class BitSet { |
| |
| private long[] words; |
| |
| BitSet(int initialCapacity) { |
| words = new long[block(initialCapacity) + 1]; |
| } |
| |
| final void clear() { |
| Arrays.fill(words, 0); |
| } |
| |
| final void set(int position) { |
| int block = block(position); |
| if (block >= words.length) { |
| long[] buf = new long[2 * block(position)]; |
| System.arraycopy(words, 0, buf, 0, words.length); |
| words = buf; |
| } |
| words[block] |= mask(position); |
| } |
| |
| final void clear(int position) { |
| int block = block(position); |
| if (block < words.length) |
| words[block] &= ~mask(position); |
| } |
| |
| final boolean get(int position) { |
| int block = block(position); |
| return block < words.length && (words[block] & mask(position)) != 0; |
| } |
| |
| final EWAHCompressedBitmap toEWAHCompressedBitmap() { |
| EWAHCompressedBitmap compressed = new EWAHCompressedBitmap( |
| words.length); |
| int runningEmptyWords = 0; |
| long lastNonEmptyWord = 0; |
| for (long word : words) { |
| if (word == 0) { |
| runningEmptyWords++; |
| continue; |
| } |
| |
| if (lastNonEmptyWord != 0) |
| compressed.addWord(lastNonEmptyWord); |
| |
| if (runningEmptyWords > 0) { |
| compressed.addStreamOfEmptyWords(false, runningEmptyWords); |
| runningEmptyWords = 0; |
| } |
| |
| lastNonEmptyWord = word; |
| } |
| int bitsThatMatter = 64 - Long.numberOfLeadingZeros(lastNonEmptyWord); |
| if (bitsThatMatter > 0) |
| compressed.addWord(lastNonEmptyWord, bitsThatMatter); |
| return compressed; |
| } |
| |
| private static final int block(int position) { |
| return position >> 6; |
| } |
| |
| private static final long mask(int position) { |
| return 1L << position; |
| } |
| } |