/*
* Copyright (C) 2014 Indeed Inc.
*
* Licensed 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 com.indeed.flamdex.datastruct;
import java.util.Arrays;
/**
* @author jsgroth
*/
public final class FastBitSet {
private final int size;
private final long[] bits;
public FastBitSet(int size) {
this.size = size;
bits = new long[(size + 64) >> 6];
}
public final boolean get(final int i) {
return (bits[i >> 6] & (1L << (i & 0x3F))) != 0;
}
public final void set(final int i) {
bits[i >> 6] |= (1L << (i & 0x3F));
}
public final void clear(final int i) {
bits[i >> 6] &= ~(1L << (i & 0x3F));
}
public final void set(final int i, final boolean v) {
if (v)
set(i);
else
clear(i);
}
public final void setRange(final int b, final int e) {
final int bt = b >> 6;
final int et = e >> 6;
if (bt != et) {
fill(bits, bt + 1, et, -1L);
bits[bt] |= (-1L << (b & 0x3F));
bits[et] |= ~(-1L << (e & 0x3F));
} else {
bits[bt] |= ((-1L << (b & 0x3F)) & ~(-1L << (e & 0x3F)));
}
}
public final void clearRange(final int b, final int e) {
final int bt = b >> 6;
final int et = e >> 6;
if (bt != et) {
fill(bits, bt + 1, et, 0L);
bits[bt] &= ~(-1L << (b & 0x3F));
bits[et] &= (-1L << (e & 0x3F));
} else {
bits[bt] &= (~(-1L << (b & 0x3F)) | (-1L << (e & 0x3F)));
}
}
public final void setAll() {
Arrays.fill(bits, -1L);
}
public final void clearAll() {
Arrays.fill(bits, 0L);
}
public final void invertAll() {
for (int i = 0; i < bits.length; ++i)
bits[i] = ~bits[i];
}
public final void and(final FastBitSet other) {
final int end = Math.min(other.bits.length, bits.length);
for (int i = 0; i < end; ++i)
bits[i] &= other.bits[i];
}
public final void or(final FastBitSet other) {
final int end = Math.min(other.bits.length, bits.length);
for (int i = 0; i < end; ++i)
bits[i] |= other.bits[i];
}
public final void nand(final FastBitSet other) {
final int end = Math.min(other.bits.length, bits.length);
for (int i = 0; i < end; ++i)
bits[i] = ~(bits[i] & other.bits[i]);
}
public final void nor(final FastBitSet other) {
final int end = Math.min(other.bits.length, bits.length);
for (int i = 0; i < end; ++i)
bits[i] = ~(bits[i] | other.bits[i]);
}
public final void xor(final FastBitSet other) {
final int end = Math.min(other.bits.length, bits.length);
for (int i = 0; i < end; ++i)
bits[i] ^= other.bits[i];
}
public final int cardinality() {
if (size == 0) return 0;
int count = 0;
for (int i = 0; i < bits.length - 1; ++i)
count += Long.bitCount(bits[i]);
return count + Long.bitCount(bits[bits.length - 1] & ~(-1L << (size & 0x3F)));
}
public final int size() {
return size;
}
public final long memoryUsage() {
return 8L * bits.length;
}
// copied from Arrays.fill(...) with the bounds check removed
private static void fill(final long[] a, final int b, final int e, final long l) {
for (int i = b; i < e; ++i)
a[i] = l;
}
public static long calculateMemoryUsage(int entries) {
final int numLongs = (entries + 64) >> 6;
return 8L * numLongs;
}
public IntIterator iterator() {
return new IntIterator();
}
public final class IntIterator {
int index = 0;
long bitBuffer = 0;
int value = 0;
public boolean next() {
while (bitBuffer == 0) {
if (index >= bits.length) {
return false;
}
bitBuffer = bits[index];
index++;
}
final long lowBit = Long.lowestOneBit(bitBuffer);
final int bitIndex = Long.bitCount(lowBit-1);
value = ((index-1)<<6)+bitIndex;
bitBuffer = bitBuffer ^ lowBit;
return true;
}
public int getValue() {
return value;
}
}
}