| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.lucene.util; |
| |
| |
| import java.util.Arrays; |
| |
| /** |
| * BitSet of fixed length (numBits), backed by accessible ({@link #getBits}) |
| * long[], accessed with a long index. Use it only if you intend to store more |
| * than 2.1B bits, otherwise you should use {@link FixedBitSet}. |
| * |
| * @lucene.internal |
| */ |
| public final class LongBitSet implements Accountable { |
| private static final long BASE_RAM_BYTES = RamUsageEstimator.shallowSizeOfInstance(LongBitSet.class); |
| |
| private final long[] bits; // Array of longs holding the bits |
| private final long numBits; // The number of bits in use |
| private final int numWords; // The exact number of longs needed to hold numBits (<= bits.length) |
| |
| /** |
| * If the given {@link LongBitSet} is large enough to hold |
| * {@code numBits+1}, returns the given bits, otherwise returns a new |
| * {@link LongBitSet} which can hold the requested number of bits. |
| * <p> |
| * <b>NOTE:</b> the returned bitset reuses the underlying {@code long[]} of |
| * the given {@code bits} if possible. Also, calling {@link #length()} on the |
| * returned bits may return a value greater than {@code numBits}. |
| */ |
| public static LongBitSet ensureCapacity(LongBitSet bits, long numBits) { |
| if (numBits < bits.numBits) { |
| return bits; |
| } else { |
| // Depends on the ghost bits being clear! |
| // (Otherwise, they may become visible in the new instance) |
| int numWords = bits2words(numBits); |
| long[] arr = bits.getBits(); |
| if (numWords >= arr.length) { |
| arr = ArrayUtil.grow(arr, numWords + 1); |
| } |
| return new LongBitSet(arr, (long)arr.length << 6); |
| } |
| } |
| |
| /** The maximum {@code numBits} supported. */ |
| public static final long MAX_NUM_BITS = 64 * (long) ArrayUtil.MAX_ARRAY_LENGTH; |
| |
| /** Returns the number of 64 bit words it would take to hold numBits */ |
| public static int bits2words(long numBits) { |
| if (numBits < 0 || numBits > MAX_NUM_BITS) { |
| throw new IllegalArgumentException("numBits must be 0 .. " + MAX_NUM_BITS + "; got: " + numBits); |
| } |
| return (int)((numBits - 1) >> 6) + 1; // I.e.: get the word-offset of the last bit and add one (make sure to use >> so 0 returns 0!) |
| } |
| |
| /** |
| * Creates a new LongBitSet. |
| * The internally allocated long array will be exactly the size needed to accommodate the numBits specified. |
| * @param numBits the number of bits needed |
| */ |
| public LongBitSet(long numBits) { |
| this.numBits = numBits; |
| bits = new long[bits2words(numBits)]; |
| numWords = bits.length; |
| } |
| |
| /** |
| * Creates a new LongBitSet using the provided long[] array as backing store. |
| * The storedBits array must be large enough to accommodate the numBits specified, but may be larger. |
| * In that case the 'extra' or 'ghost' bits must be clear (or they may provoke spurious side-effects) |
| * @param storedBits the array to use as backing store |
| * @param numBits the number of bits actually needed |
| */ |
| public LongBitSet(long[] storedBits, long numBits) { |
| this.numWords = bits2words(numBits); |
| if (numWords > storedBits.length) { |
| throw new IllegalArgumentException("The given long array is too small to hold " + numBits + " bits"); |
| } |
| this.numBits = numBits; |
| this.bits = storedBits; |
| |
| assert verifyGhostBitsClear(); |
| } |
| |
| /** |
| * Checks if the bits past numBits are clear. |
| * Some methods rely on this implicit assumption: search for "Depends on the ghost bits being clear!" |
| * @return true if the bits past numBits are clear. |
| */ |
| private boolean verifyGhostBitsClear() { |
| for (int i = numWords; i < bits.length; i++) { |
| if (bits[i] != 0) return false; |
| } |
| |
| if ((numBits & 0x3f) == 0) return true; |
| |
| long mask = -1L << numBits; |
| |
| return (bits[numWords - 1] & mask) == 0; |
| } |
| |
| /** Returns the number of bits stored in this bitset. */ |
| public long length() { |
| return numBits; |
| } |
| |
| /** Expert. */ |
| public long[] getBits() { |
| return bits; |
| } |
| |
| /** Returns number of set bits. NOTE: this visits every |
| * long in the backing bits array, and the result is not |
| * internally cached! |
| */ |
| public long cardinality() { |
| // Depends on the ghost bits being clear! |
| return BitUtil.pop_array(bits, 0, numWords); |
| } |
| |
| public boolean get(long index) { |
| assert index >= 0 && index < numBits: "index=" + index + ", numBits=" + numBits; |
| int i = (int) (index >> 6); // div 64 |
| // signed shift will keep a negative index and force an |
| // array-index-out-of-bounds-exception, removing the need for an explicit check. |
| long bitmask = 1L << index; |
| return (bits[i] & bitmask) != 0; |
| } |
| |
| public void set(long index) { |
| assert index >= 0 && index < numBits: "index=" + index + " numBits=" + numBits; |
| int wordNum = (int) (index >> 6); // div 64 |
| long bitmask = 1L << index; |
| bits[wordNum] |= bitmask; |
| } |
| |
| public boolean getAndSet(long index) { |
| assert index >= 0 && index < numBits: "index=" + index + ", numBits=" + numBits; |
| int wordNum = (int) (index >> 6); // div 64 |
| long bitmask = 1L << index; |
| boolean val = (bits[wordNum] & bitmask) != 0; |
| bits[wordNum] |= bitmask; |
| return val; |
| } |
| |
| public void clear(long index) { |
| assert index >= 0 && index < numBits: "index=" + index + ", numBits=" + numBits; |
| int wordNum = (int) (index >> 6); |
| long bitmask = 1L << index; |
| bits[wordNum] &= ~bitmask; |
| } |
| |
| public boolean getAndClear(long index) { |
| assert index >= 0 && index < numBits: "index=" + index + ", numBits=" + numBits; |
| int wordNum = (int) (index >> 6); // div 64 |
| long bitmask = 1L << index; |
| boolean val = (bits[wordNum] & bitmask) != 0; |
| bits[wordNum] &= ~bitmask; |
| return val; |
| } |
| |
| /** Returns the index of the first set bit starting at the index specified. |
| * -1 is returned if there are no more set bits. |
| */ |
| public long nextSetBit(long index) { |
| // Depends on the ghost bits being clear! |
| assert index >= 0 && index < numBits: "index=" + index + ", numBits=" + numBits; |
| int i = (int) (index >> 6); |
| long word = bits[i] >> index; // skip all the bits to the right of index |
| |
| if (word!=0) { |
| return index + Long.numberOfTrailingZeros(word); |
| } |
| |
| while(++i < numWords) { |
| word = bits[i]; |
| if (word != 0) { |
| return (i<<6) + Long.numberOfTrailingZeros(word); |
| } |
| } |
| |
| return -1; |
| } |
| |
| /** Returns the index of the last set bit before or on the index specified. |
| * -1 is returned if there are no more set bits. |
| */ |
| public long prevSetBit(long index) { |
| assert index >= 0 && index < numBits: "index=" + index + " numBits=" + numBits; |
| int i = (int) (index >> 6); |
| final int subIndex = (int) (index & 0x3f); // index within the word |
| long word = (bits[i] << (63-subIndex)); // skip all the bits to the left of index |
| |
| if (word != 0) { |
| return (i << 6) + subIndex - Long.numberOfLeadingZeros(word); // See LUCENE-3197 |
| } |
| |
| while (--i >= 0) { |
| word = bits[i]; |
| if (word !=0 ) { |
| return (i << 6) + 63 - Long.numberOfLeadingZeros(word); |
| } |
| } |
| |
| return -1; |
| } |
| |
| /** this = this OR other */ |
| public void or(LongBitSet other) { |
| assert other.numWords <= numWords : "numWords=" + numWords + ", other.numWords=" + other.numWords; |
| int pos = Math.min(numWords, other.numWords); |
| while (--pos >= 0) { |
| bits[pos] |= other.bits[pos]; |
| } |
| } |
| |
| /** this = this XOR other */ |
| public void xor(LongBitSet other) { |
| assert other.numWords <= numWords : "numWords=" + numWords + ", other.numWords=" + other.numWords; |
| int pos = Math.min(numWords, other.numWords); |
| while (--pos >= 0) { |
| bits[pos] ^= other.bits[pos]; |
| } |
| } |
| |
| /** returns true if the sets have any elements in common */ |
| public boolean intersects(LongBitSet other) { |
| // Depends on the ghost bits being clear! |
| int pos = Math.min(numWords, other.numWords); |
| while (--pos>=0) { |
| if ((bits[pos] & other.bits[pos]) != 0) return true; |
| } |
| return false; |
| } |
| |
| /** this = this AND other */ |
| public void and(LongBitSet other) { |
| int pos = Math.min(numWords, other.numWords); |
| while (--pos >= 0) { |
| bits[pos] &= other.bits[pos]; |
| } |
| if (numWords > other.numWords) { |
| Arrays.fill(bits, other.numWords, numWords, 0L); |
| } |
| } |
| |
| /** this = this AND NOT other */ |
| public void andNot(LongBitSet other) { |
| int pos = Math.min(numWords, other.numWords); |
| while (--pos >= 0) { |
| bits[pos] &= ~other.bits[pos]; |
| } |
| } |
| |
| /** |
| * Scans the backing store to check if all bits are clear. |
| * The method is deliberately not called "isEmpty" to emphasize it is not low cost (as isEmpty usually is). |
| * @return true if all bits are clear. |
| */ |
| public boolean scanIsEmpty() { |
| // This 'slow' implementation is still faster than any external one could be |
| // (e.g.: (bitSet.length() == 0 || bitSet.nextSetBit(0) == -1)) |
| // especially for small BitSets |
| // Depends on the ghost bits being clear! |
| final int count = numWords; |
| |
| for (int i = 0; i < count; i++) { |
| if (bits[i] != 0) return false; |
| } |
| |
| return true; |
| } |
| |
| /** Flips a range of bits |
| * |
| * @param startIndex lower index |
| * @param endIndex one-past the last bit to flip |
| */ |
| public void flip(long startIndex, long endIndex) { |
| assert startIndex >= 0 && startIndex < numBits; |
| assert endIndex >= 0 && endIndex <= numBits; |
| if (endIndex <= startIndex) { |
| return; |
| } |
| |
| int startWord = (int) (startIndex >> 6); |
| int endWord = (int) ((endIndex-1) >> 6); |
| |
| /*** Grrr, java shifting uses only the lower 6 bits of the count so -1L>>>64 == -1 |
| * for that reason, make sure not to use endmask if the bits to flip will |
| * be zero in the last word (redefine endWord to be the last changed...) |
| long startmask = -1L << (startIndex & 0x3f); // example: 11111...111000 |
| long endmask = -1L >>> (64-(endIndex & 0x3f)); // example: 00111...111111 |
| ***/ |
| |
| long startmask = -1L << startIndex; |
| long endmask = -1L >>> -endIndex; // 64-(endIndex&0x3f) is the same as -endIndex since only the lowest 6 bits are used |
| |
| if (startWord == endWord) { |
| bits[startWord] ^= (startmask & endmask); |
| return; |
| } |
| |
| bits[startWord] ^= startmask; |
| |
| for (int i=startWord+1; i<endWord; i++) { |
| bits[i] = ~bits[i]; |
| } |
| |
| bits[endWord] ^= endmask; |
| } |
| |
| /** Flip the bit at the provided index. */ |
| public void flip(long index) { |
| assert index >= 0 && index < numBits: "index=" + index + " numBits=" + numBits; |
| int wordNum = (int) (index >> 6); // div 64 |
| long bitmask = 1L << index; // mod 64 is implicit |
| bits[wordNum] ^= bitmask; |
| } |
| |
| /** Sets a range of bits |
| * |
| * @param startIndex lower index |
| * @param endIndex one-past the last bit to set |
| */ |
| public void set(long startIndex, long endIndex) { |
| assert startIndex >= 0 && startIndex < numBits : "startIndex=" + startIndex + ", numBits=" + numBits; |
| assert endIndex >= 0 && endIndex <= numBits : "endIndex=" + endIndex + ", numBits=" + numBits; |
| if (endIndex <= startIndex) { |
| return; |
| } |
| |
| int startWord = (int) (startIndex >> 6); |
| int endWord = (int) ((endIndex-1) >> 6); |
| |
| long startmask = -1L << startIndex; |
| long endmask = -1L >>> -endIndex; // 64-(endIndex&0x3f) is the same as -endIndex since only the lowest 6 bits are used |
| |
| if (startWord == endWord) { |
| bits[startWord] |= (startmask & endmask); |
| return; |
| } |
| |
| bits[startWord] |= startmask; |
| Arrays.fill(bits, startWord+1, endWord, -1L); |
| bits[endWord] |= endmask; |
| } |
| |
| /** Clears a range of bits. |
| * |
| * @param startIndex lower index |
| * @param endIndex one-past the last bit to clear |
| */ |
| public void clear(long startIndex, long endIndex) { |
| assert startIndex >= 0 && startIndex < numBits : "startIndex=" + startIndex + ", numBits=" + numBits; |
| assert endIndex >= 0 && endIndex <= numBits : "endIndex=" + endIndex + ", numBits=" + numBits; |
| if (endIndex <= startIndex) { |
| return; |
| } |
| |
| int startWord = (int) (startIndex >> 6); |
| int endWord = (int) ((endIndex-1) >> 6); |
| |
| long startmask = -1L << startIndex; |
| long endmask = -1L >>> -endIndex; // 64-(endIndex&0x3f) is the same as -endIndex since only the lowest 6 bits are used |
| |
| // invert masks since we are clearing |
| startmask = ~startmask; |
| endmask = ~endmask; |
| |
| if (startWord == endWord) { |
| bits[startWord] &= (startmask | endmask); |
| return; |
| } |
| |
| bits[startWord] &= startmask; |
| Arrays.fill(bits, startWord+1, endWord, 0L); |
| bits[endWord] &= endmask; |
| } |
| |
| @Override |
| public LongBitSet clone() { |
| long[] bits = new long[this.bits.length]; |
| System.arraycopy(this.bits, 0, bits, 0, numWords); |
| return new LongBitSet(bits, numBits); |
| } |
| |
| /** returns true if both sets have the same bits set */ |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) { |
| return true; |
| } |
| if (!(o instanceof LongBitSet)) { |
| return false; |
| } |
| LongBitSet other = (LongBitSet) o; |
| if (numBits != other.numBits) { |
| return false; |
| } |
| // Depends on the ghost bits being clear! |
| return Arrays.equals(bits, other.bits); |
| } |
| |
| @Override |
| public int hashCode() { |
| // Depends on the ghost bits being clear! |
| long h = 0; |
| for (int i = numWords; --i>=0;) { |
| h ^= bits[i]; |
| h = (h << 1) | (h >>> 63); // rotate left |
| } |
| // fold leftmost bits into right and add a constant to prevent |
| // empty sets from returning 0, which is too common. |
| return (int) ((h>>32) ^ h) + 0x98761234; |
| } |
| |
| @Override |
| public long ramBytesUsed() { |
| return BASE_RAM_BYTES + |
| RamUsageEstimator.sizeOfObject(bits); |
| } |
| } |