org.jooq.tools.Longs Maven / Gradle / Ivy
/*
* Copyright (C) 2008 The Guava Authors
*
* 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 org.jooq.tools;
import java.util.Arrays;
/**
* Static utility methods pertaining to {@code long} primitives, that are not already found in
* either {@link Long} or {@link Arrays}.
*
* See the Guava User Guide article on primitive utilities.
*
* @author Kevin Bourrillion
* @since 1.0
*/
public final class Longs {
private Longs() {}
// adapted from com.google.common.primitives.Longs#tryParse()
// modified for performance and to allow parsing numbers with leading '+'
public static Long tryParse(String string) {
if (string.isEmpty())
return null;
int radix = 10;
char firstChar = string.charAt(0);
boolean negative = firstChar == '-';
int index = negative || firstChar == '+' ? 1 : 0;
int length = string.length();
if (index == length)
return null;
int digit = Character.digit(string.charAt(index++), 10);
if (digit < 0 || digit >= radix)
return null;
long accum = -digit;
long cap = Long.MIN_VALUE / radix;
while (index < length) {
digit = Character.digit(string.charAt(index++), 10);
if (digit < 0 || digit >= radix || accum < cap)
return null;
accum *= radix;
if (accum < Long.MIN_VALUE + digit)
return null;
accum -= digit;
}
if (negative)
return accum;
else if (accum == Long.MIN_VALUE)
return null;
else
return -accum;
}
}