| /* |
| * 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 com.googlecode.javaewah.EWAHCompressedBitmap; |
| import com.googlecode.javaewah.IntIterator; |
| |
| /** |
| * A wrapper around the EWAHCompressedBitmap optimized for the contains |
| * operation. |
| */ |
| final class InflatingBitSet { |
| private static final long[] EMPTY = new long[0]; |
| |
| private final EWAHCompressedBitmap bitmap; |
| |
| private IntIterator iterator; |
| |
| private long[] inflated; |
| |
| private int nextPosition = -1; |
| |
| private final int sizeInBits; |
| |
| InflatingBitSet(EWAHCompressedBitmap bitmap) { |
| this(bitmap, EMPTY); |
| } |
| |
| private InflatingBitSet(EWAHCompressedBitmap orBitmap, long[] inflated) { |
| this.bitmap = orBitmap; |
| this.inflated = inflated; |
| this.sizeInBits = bitmap.sizeInBits(); |
| } |
| |
| final boolean maybeContains(int position) { |
| if (get(position)) |
| return true; |
| return nextPosition <= position && position < sizeInBits; |
| } |
| |
| final boolean contains(int position) { |
| if (get(position)) |
| return true; |
| if (position <= nextPosition || position >= sizeInBits) |
| return position == nextPosition; |
| |
| if (iterator == null) { |
| iterator = bitmap.intIterator(); |
| if (iterator.hasNext()) |
| nextPosition = iterator.next(); |
| else |
| return false; |
| } else if (!iterator.hasNext()) |
| return false; |
| |
| int positionBlock = block(position); |
| if (positionBlock >= inflated.length) { |
| long[] tmp = new long[block(sizeInBits) + 1]; |
| System.arraycopy(inflated, 0, tmp, 0, inflated.length); |
| inflated = tmp; |
| } |
| |
| int block = block(nextPosition); |
| long word = mask(nextPosition); |
| int end = Math.max(nextPosition, position) | 63; |
| while (iterator.hasNext()) { |
| nextPosition = iterator.next(); |
| if (end < nextPosition) |
| break; |
| |
| int b = block(nextPosition); |
| long m = mask(nextPosition); |
| if (block == b) { |
| word |= m; |
| } else { |
| inflated[block] = word; |
| block = b; |
| word = m; |
| } |
| } |
| inflated[block] = word; |
| return block == positionBlock && (word & mask(position)) != 0; |
| } |
| |
| private final boolean get(int position) { |
| int b = block(position); |
| return b < inflated.length && (inflated[b] & mask(position)) != 0; |
| } |
| |
| private static final int block(int position) { |
| return position >> 6; |
| } |
| |
| private static final long mask(int position) { |
| return 1L << position; |
| } |
| |
| private final boolean isEmpty() { |
| return sizeInBits == 0; |
| } |
| |
| final InflatingBitSet or(EWAHCompressedBitmap other) { |
| if (other.sizeInBits() == 0) |
| return this; |
| return new InflatingBitSet(bitmap.or(other), inflated); |
| } |
| |
| final InflatingBitSet andNot(EWAHCompressedBitmap other) { |
| if (isEmpty()) |
| return this; |
| return new InflatingBitSet(bitmap.andNot(other)); |
| } |
| |
| final InflatingBitSet xor(EWAHCompressedBitmap other) { |
| if (isEmpty()) { |
| if (other.sizeInBits() == 0) |
| return this; |
| return new InflatingBitSet(other); |
| } |
| return new InflatingBitSet(bitmap.xor(other)); |
| } |
| |
| final EWAHCompressedBitmap getBitmap() { |
| return bitmap; |
| } |
| } |