| /* |
| * Copyright (C) 2012, Google Inc. 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 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; |
| } |
| } |