/*
* 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.facebook.presto.array;
// Note: this code was forked from fastutil (http://fastutil.di.unimi.it/)
// Copyright (C) 2010-2013 Sebastiano Vigna
final class BigArrays
{
private BigArrays() {}
/**
* Initial number of segments to support in array.
*/
public static final int INITIAL_SEGMENTS = 1024;
/**
* The shift used to compute the segment associated with an index (equivalently, the logarithm of the segment size).
*/
public static final int SEGMENT_SHIFT = 10;
/**
* Size of a single segment of a BigArray
*/
public static final int SEGMENT_SIZE = 1 << SEGMENT_SHIFT;
/**
* The mask used to compute the offset associated to an index.
*/
public static final int SEGMENT_MASK = SEGMENT_SIZE - 1;
/**
* Computes the segment associated with a given index.
*
* @param index an index into a big array.
* @return the associated segment.
*/
@SuppressWarnings("NumericCastThatLosesPrecision")
public static int segment(long index)
{
return (int) (index >>> SEGMENT_SHIFT);
}
/**
* Computes the offset associated with a given index.
*
* @param index an index into a big array.
* @return the associated offset (in the associated {@linkplain #segment(long) segment}).
*/
@SuppressWarnings("NumericCastThatLosesPrecision")
public static int offset(long index)
{
return (int) (index & SEGMENT_MASK);
}
}