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

     
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 * 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] 
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 */

/*
 * @(#)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);
  }
}

   
    
    
    
    
  








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