82b0db5013
Motivation: Netty uses own Integer.compare and Long.compare methods. Since Java 7 we can use Java implementation instead. Modification: Remove own implementation Result: Less code to maintain
68 lines
2.8 KiB
Java
68 lines
2.8 KiB
Java
/*
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* Copyright 2015 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License, version 2.0 (the
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* "License"); you may not use this file except in compliance with the License. You may obtain a
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* copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software distributed under the License
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* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
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* or implied. See the License for the specific language governing permissions and limitations under
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* the License.
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*/
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package io.netty.util.internal;
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/**
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* Math utility methods.
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*/
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public final class MathUtil {
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private MathUtil() {
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}
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/**
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* Fast method of finding the next power of 2 greater than or equal to the supplied value.
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*
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* <p>If the value is {@code <= 0} then 1 will be returned.
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* This method is not suitable for {@link Integer#MIN_VALUE} or numbers greater than 2^30.
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*
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* @param value from which to search for next power of 2
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* @return The next power of 2 or the value itself if it is a power of 2
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*/
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public static int findNextPositivePowerOfTwo(final int value) {
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assert value > Integer.MIN_VALUE && value < 0x40000000;
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return 1 << (32 - Integer.numberOfLeadingZeros(value - 1));
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}
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/**
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* Fast method of finding the next power of 2 greater than or equal to the supplied value.
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* <p>This method will do runtime bounds checking and call {@link #findNextPositivePowerOfTwo(int)} if within a
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* valid range.
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* @param value from which to search for next power of 2
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* @return The next power of 2 or the value itself if it is a power of 2.
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* <p>Special cases for return values are as follows:
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* <ul>
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* <li>{@code <= 0} -> 1</li>
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* <li>{@code >= 2^30} -> 2^30</li>
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* </ul>
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*/
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public static int safeFindNextPositivePowerOfTwo(final int value) {
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return value <= 0 ? 1 : value >= 0x40000000 ? 0x40000000 : findNextPositivePowerOfTwo(value);
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}
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/**
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* Determine if the requested {@code index} and {@code length} will fit within {@code capacity}.
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* @param index The starting index.
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* @param length The length which will be utilized (starting from {@code index}).
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* @param capacity The capacity that {@code index + length} is allowed to be within.
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* @return {@code true} if the requested {@code index} and {@code length} will fit within {@code capacity}.
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* {@code false} if this would result in an index out of bounds exception.
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*/
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public static boolean isOutOfBounds(int index, int length, int capacity) {
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return (index | length | (index + length) | (capacity - (index + length))) < 0;
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}
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}
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