org/argeo/util/BytesUtils.java

   1 package org.argeo.util;
   2
   3 /** Utilities around byte arrays and byte buffers. */
   4 public class BytesUtils {
   5         final private static char[] hexArray = "0123456789abcdef".toCharArray();
   6
   7         /** Convert two longs to a byte array with length 16. */
   8         public static byte[] toBytes(long long1, long long2) {
   9                 byte[] result = new byte[16];
  10                 for (int i = 0; i < 8; i++)
  11                         result[i] = (byte) ((long1 >> ((7 - i) * 8)) & 0xff);
  12                 for (int i = 8; i < 16; i++)
  13                         result[i] = (byte) ((long2 >> ((15 - i) * 8)) & 0xff);
  14                 return result;
  15         }
  16
  17         public static void copyBytes(long long1, long long2, byte[] arr, int offset) {
  18                 assert arr.length >= 16 + offset;
  19                 for (int i = offset; i < 8 + offset; i++)
  20                         arr[i] = (byte) ((long1 >> ((7 - i) * 8)) & 0xff);
  21                 for (int i = 8 + offset; i < 16 + offset; i++)
  22                         arr[i] = (byte) ((long2 >> ((15 - i) * 8)) & 0xff);
  23         }
  24
  25         /** Converts a byte array to an hex String. */
  26         public static String toHexString(byte[] bytes) {
  27                 char[] hexChars = new char[bytes.length * 2];
  28                 for (int j = 0; j < bytes.length; j++) {
  29                         int v = bytes[j] & 0xFF;
  30                         hexChars[j * 2] = hexArray[v >>> 4];
  31                         hexChars[j * 2 + 1] = hexArray[v & 0x0F];
  32                 }
  33                 return new String(hexChars);
  34         }
  35
  36         /** singleton */
  37         private BytesUtils() {
  38
  39         }
  40
  41 }