/*
* 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 com.indeed.util.mmap.LongArray;
import com.indeed.util.mmap.MMapBuffer;
import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
/**
* @author jsgroth
*
* copy-paste of FastBitSet that operates on an mmap'd file instead of a long array
*/
public final class MMapFastBitSet implements Closeable {
private final int size;
private final int arraySize;
private final MMapBuffer buffer;
private final int bufferLength;
private final LongArray bits;
public MMapFastBitSet(File file, int size, FileChannel.MapMode mapMode) throws IOException {
this.size = size;
this.arraySize = (size + 64) >> 6;
this.bufferLength = arraySize * 8;
this.buffer = new MMapBuffer(file, 0, bufferLength, mapMode, ByteOrder.LITTLE_ENDIAN);
this.bits = buffer.memory().longArray(0, arraySize);
}
public final boolean get(final int i) {
return (bits.get(i >> 6) & (1L << (i & 0x3F))) != 0;
}
public final void set(final int i) {
bits.set(i >> 6, bits.get(i >> 6) | (1L << (i & 0x3F)));
}
public final void clear(final int i) {
bits.set(i >> 6, bits.get(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.set(bt, bits.get(bt) | (-1L << (b & 0x3F)));
bits.set(et, bits.get(et) | ~(-1L << (e & 0x3F)));
} else {
bits.set(bt, bits.get(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.set(bt, bits.get(bt) & ~(-1L << (b & 0x3F)));
bits.set(et, bits.get(et) & (-1L << (e & 0x3F)));
} else {
bits.set(bt, bits.get(bt) & (~(-1L << (b & 0x3F)) | (-1L << (e & 0x3F))));
}
}
public final void setAll() {
fill(bits, 0, arraySize, -1L);
}
public final void clearAll() {
fill(bits, 0, arraySize, 0L);
}
public final void invertAll() {
for (int i = 0; i < arraySize; ++i)
bits.set(i, ~bits.get(i));
}
public final void and(final MMapFastBitSet other) {
for (int i = 0; i < arraySize; ++i)
bits.set(i, bits.get(i) & other.bits.get(i));
}
public final void or(final MMapFastBitSet other) {
for (int i = 0; i < arraySize; ++i)
bits.set(i, bits.get(i) | other.bits.get(i));
}
public final void nand(final MMapFastBitSet other) {
for (int i = 0; i < arraySize; ++i)
bits.set(i, ~(bits.get(i) & other.bits.get(i)));
}
public final void nor(final MMapFastBitSet other) {
for (int i = 0; i < arraySize; ++i)
bits.set(i, ~(bits.get(i) | other.bits.get(i)));
}
public final void xor(final MMapFastBitSet other) {
for (int i = 0; i < arraySize; ++i)
bits.set(i, bits.get(i) ^ other.bits.get(i));
}
public final int cardinality() {
if (size == 0) return 0;
int count = 0;
for (int i = 0; i < arraySize - 1; ++i)
count += Long.bitCount(bits.get(i));
return count + Long.bitCount(bits.get(arraySize - 1) & ~(-1L << (size & 0x3F)));
}
public final int size() {
return size;
}
public final long memoryUsage() {
return 0;
}
private static void fill(final LongArray a, final int b, final int e, final long l) {
for (int i = b; i < e; ++i)
a.set(i, l);
}
public void sync() throws IOException {
buffer.sync(0, bufferLength);
}
@Override
public void close() throws IOException {
buffer.close();
}
}