/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.sshd.common.util;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.stream.IntStream;
/**
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public final class NumberUtils {
/**
* A {@link List} of all the {@link Class} types used to represent the
* primitive numerical values
*/
public static final List<Class<?>> NUMERIC_PRIMITIVE_CLASSES =
GenericUtils.unmodifiableList(
Byte.TYPE, Short.TYPE, Integer.TYPE, Long.TYPE,
Float.TYPE, Double.TYPE
);
/**
* A {@link List} containing all the pure powers of 2 for a {@code long}
* value. The value at index <I>n</I> is 2 to the power of <I>n</I>
*/
public static final List<Long> POWERS_OF_TWO =
GenericUtils.unmodifiableList(IntStream.range(0, 64)
.mapToObj(i -> 1L << i));
private NumberUtils() {
throw new UnsupportedOperationException("No instance");
}
public static boolean isPowerOf2(long value) {
for (Long l : POWERS_OF_TWO) {
if (value == l) {
return true;
}
}
return false;
}
public static long getNextPowerOf2(long value) {
long j = 1L;
while (j < value) {
j <<= 1;
}
return j;
}
public static int getNextPowerOf2(int value) {
int j = 1;
while (j < value) {
j <<= 1;
}
return j;
}
public static int hashCode(long... values) {
return Arrays.hashCode(values);
}
public static int hashCode(int... values) {
return Arrays.hashCode(values);
}
public static int hashCode(byte... values) {
return Arrays.hashCode(values);
}
public static int hashCode(byte[] a, int offset, int len) {
if (len == 0) {
return 0;
}
int result = 1;
for (int pos = offset, count = 0; count < len; pos++, count++) {
byte element = a[pos];
result = 31 * result + element;
}
return result;
}
public static int diffOffset(byte[] a1, int startPos1, byte[] a2, int startPos2, int len) {
for (int pos1 = startPos1, pos2 = startPos2, count = 0; count < len; pos1++, pos2++, count++) {
byte v1 = a1[pos1];
byte v2 = a2[pos2];
if (v1 != v2) {
return count;
}
}
return -1;
}
/**
* @param clazz The {@link Class} to examine - ignored if {@code null}
* @return If the class is a {@link Number} or one of the primitive numerical types
* @see #NUMERIC_PRIMITIVE_CLASSES
*/
public static boolean isNumericClass(Class<?> clazz) {
if (clazz == null) {
return false;
}
// turns out that the primitive types are not assignable to Number
if (Number.class.isAssignableFrom(clazz)) {
return true;
}
return NUMERIC_PRIMITIVE_CLASSES.indexOf(clazz) >= 0;
}
/**
* Converts a {@link Number} into an {@link Integer} if not already such
*
* @param n The {@link Number} - ignored if {@code null}
* @return The equivalent {@link Integer} value
*/
public static Integer toInteger(Number n) {
if (n == null) {
return null;
} else if (n instanceof Integer) {
return (Integer) n;
} else {
return n.intValue();
}
}
public static String join(CharSequence separator, long... values) {
if (NumberUtils.isEmpty(values)) {
return "";
}
StringBuilder sb = new StringBuilder(values.length * Byte.SIZE);
for (long v : values) {
if (sb.length() > 0) {
sb.append(separator);
}
sb.append(v);
}
return sb.toString();
}
public static String join(char separator, long... values) {
if (NumberUtils.isEmpty(values)) {
return "";
}
StringBuilder sb = new StringBuilder(values.length * Byte.SIZE);
for (long v : values) {
if (sb.length() > 0) {
sb.append(separator);
}
sb.append(v);
}
return sb.toString();
}
public static String join(CharSequence separator, boolean unsigned, byte... values) {
if (NumberUtils.isEmpty(values)) {
return "";
}
StringBuilder sb = new StringBuilder(values.length * Byte.SIZE);
for (byte v : values) {
if (sb.length() > 0) {
sb.append(separator);
}
sb.append(unsigned ? (v & 0xFF) : v);
}
return sb.toString();
}
public static String join(char separator, boolean unsigned, byte... values) {
if (NumberUtils.isEmpty(values)) {
return "";
}
StringBuilder sb = new StringBuilder(values.length * Byte.SIZE);
for (byte v : values) {
if (sb.length() > 0) {
sb.append(separator);
}
sb.append(unsigned ? (v & 0xFF) : v);
}
return sb.toString();
}
public static String join(CharSequence separator, int... values) {
if (NumberUtils.isEmpty(values)) {
return "";
}
StringBuilder sb = new StringBuilder(values.length * Byte.SIZE);
for (int v : values) {
if (sb.length() > 0) {
sb.append(separator);
}
sb.append(v);
}
return sb.toString();
}
public static String join(char separator, int... values) {
if (NumberUtils.isEmpty(values)) {
return "";
}
StringBuilder sb = new StringBuilder(values.length * Byte.SIZE);
for (int v : values) {
if (sb.length() > 0) {
sb.append(separator);
}
sb.append(v);
}
return sb.toString();
}
public static boolean isEmpty(byte[] a) {
return NumberUtils.length(a) <= 0;
}
public static boolean isEmpty(int[] a) {
return NumberUtils.length(a) <= 0;
}
public static boolean isEmpty(long[] a) {
return NumberUtils.length(a) <= 0;
}
public static int length(byte... a) {
return a == null ? 0 : a.length;
}
public static int length(int... a) {
return a == null ? 0 : a.length;
}
public static int length(long... a) {
return a == null ? 0 : a.length;
}
public static List<Integer> asList(int... values) {
int len = length(values);
if (len <= 0) {
return Collections.emptyList();
}
List<Integer> l = new ArrayList<>(len);
for (int v : values) {
l.add(v);
}
return l;
}
/**
* Checks if optional sign and all others are '0'-'9'
* @param cs The {@link CharSequence} to check
* @return {@code true} if valid integer number
*/
public static boolean isIntegerNumber(CharSequence cs) {
if (GenericUtils.isEmpty(cs)) {
return false;
}
for (int index = 0; index < cs.length(); index++) {
char c = cs.charAt(0);
if ((c >= '0') && (c <= '9')) {
continue;
}
if ((c == '+') || (c == '-')) {
if (index == 0) {
continue;
}
}
return false;
}
return true;
}
}