Convert the bytes within the specified range of the given byte array into a signed long : Byte Array « File Input Output « Java
Convert the bytes within the specified range of the given byte array into a signed long
/*
* The contents of this file are subject to the terms
* of the Common Development and Distribution License
* (the "License"). You may not use this file except
* in compliance with the License.
*
* You can obtain a copy of the license at
* glassfish/bootstrap/legal/CDDLv1.0.txt or
* https://glassfish.dev.java.net/public/CDDLv1.0.html.
* See the License for the specific language governing
* permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL
* HEADER in each file and include the License file at
* glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
* add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your
* own identifying information: Portions Copyright [yyyy]
* [name of copyright owner]
*/
/*
* @(#)ASCIIUtility.java 1.10 05/08/29
*
* Copyright 1997-2005 Sun Microsystems, Inc. All Rights Reserved.
*/
public class Utils {
/**
* Convert the bytes within the specified range of the given byte array into a
* signed long . The range extends from <code>start</code> till, but not
* including <code>end</code>.
* <p>
*/
public static long parseLong(byte[] b, int start, int end) throws NumberFormatException {
return parseLong(b, start, end, 10);
}
/**
* Convert the bytes within the specified range of the given byte array into a
* signed long in the given radix . The range extends from <code>start</code>
* till, but not including <code>end</code>.
* <p>
*
* Based on java.lang.Long.parseLong()
*/
public static long parseLong(byte[] b, int start, int end, int radix)
throws NumberFormatException {
if (b == null)
throw new NumberFormatException("null");
long result = 0;
boolean negative = false;
int i = start;
long limit;
long multmin;
int digit;
if (end > start) {
if (b[i] == '-') {
negative = true;
limit = Long.MIN_VALUE;
i++;
} else {
limit = -Long.MAX_VALUE;
}
multmin = limit / radix;
if (i < end) {
digit = Character.digit((char) b[i++], radix);
if (digit < 0) {
throw new NumberFormatException("illegal number: " + toString(b, start, end));
} else {
result = -digit;
}
}
while (i < end) {
// Accumulating negatively avoids surprises near MAX_VALUE
digit = Character.digit((char) b[i++], radix);
if (digit < 0) {
throw new NumberFormatException("illegal number");
}
if (result < multmin) {
throw new NumberFormatException("illegal number");
}
result *= radix;
if (result < limit + digit) {
throw new NumberFormatException("illegal number");
}
result -= digit;
}
} else {
throw new NumberFormatException("illegal number");
}
if (negative) {
if (i > start + 1) {
return result;
} else { /* Only got "-" */
throw new NumberFormatException("illegal number");
}
} else {
return -result;
}
}
/**
* Convert the bytes within the specified range of the given byte array into a
* String. The range extends from <code>start</code> till, but not including
* <code>end</code>.
* <p>
*/
public static String toString(byte[] b, int start, int end) {
int size = end - start;
char[] theChars = new char[size];
for (int i = 0, j = start; i < size;)
theChars[i++] = (char) (b[j++] & 0xff);
return new String(theChars);
}
}
