org.gridkit.jvmtool.util.PagedLongArray Maven / Gradle / Ivy
package org.gridkit.jvmtool.util;
/**
* Copyright 2014 Alexey Ragozin
*
* 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.
*/
import java.util.Arrays;
class PagedLongArray implements LongArray {
private final static int PAGE_BITS = 10;
private final static int PAGE_MASK = ~(-1 << PAGE_BITS);
private final static int PAGE_SIZE = 1 << PAGE_BITS;
public final static long NULL_VALUE = 0;
protected long lastIndex = -1;
protected long[][] array = new long[16][];
public long get(long n) {
int bi = (int) (n >> PAGE_BITS);
if (bi >= array.length) {
return NULL_VALUE;
}
if (bi < 0) {
throw new ArrayIndexOutOfBoundsException(bi);
}
long[] page = array[bi];
if (page == null) {
return NULL_VALUE;
}
return page[(int) (n & PAGE_MASK)];
}
public long seekNext(long start) {
long n = start;
while(true) {
int bi = (int) (n >> PAGE_BITS);
if (bi >= array.length) {
return -1;
}
if (bi < 0) {
throw new ArrayIndexOutOfBoundsException(bi);
}
long[] page = array[bi];
if (page == null) {
n = PAGE_SIZE * (bi + 1);
continue;
}
if (page[(int) (n & PAGE_MASK)] != 0) {
return n;
}
++n;
}
}
public void set(long n, long value) {
lastIndex = Math.max(lastIndex, n);
int bi = (int) (n >> PAGE_BITS);
if (bi >= array.length) {
array = Arrays.copyOf(array, bi + 1);
}
long[] page = array[bi];
if (page == null) {
if (value == NULL_VALUE) {
return;
}
array[bi] = page = new long[PAGE_SIZE];
Arrays.fill(page, NULL_VALUE);
}
page[(int) (n & PAGE_MASK)] = value;
}
}