src/org/objectweb/cjdbc/common/stream/encoding/HexaEncoding.java

説明を見る。

package org.objectweb.cjdbc.common.stream.encoding;

public class HexaEncoding
{
  public static final String data2hex(byte[] data)
  {
    if (data == null)
      return null;

    int len = data.length;
    StringBuffer buf = new StringBuffer(len * 2);
    for (int pos = 0; pos < len; pos++)
      buf.append(toHexChar((data[pos] >>> 4) & 0x0F)).append(
          toHexChar(data[pos] & 0x0F));
    return buf.toString();
  }

  public static final byte[] hex2data(String str)
  {
    if (str == null)
      return new byte[0];

    int len = str.length();
    char hex[] = str.toCharArray();
    byte[] buf = new byte[len / 2];

    for (int pos = 0; pos < len / 2; pos++)
      buf[pos] = (byte) (((toDataNibble(hex[2 * pos]) << 4) & 0xF0) | (toDataNibble(hex[2 * pos + 1]) & 0x0F));

    return buf;
  }

  public static char toHexChar(int i)
  {
    if ((0 <= i) && (i <= 9))
      return (char) ('0' + i);
    else
      return (char) ('a' + (i - 10));
  }

  public static byte toDataNibble(char c)
  {
    if (('0' <= c) && (c <= '9'))
      return (byte) ((byte) c - (byte) '0');
    else if (('a' <= c) && (c <= 'f'))
      return (byte) ((byte) c - (byte) 'a' + 10);
    else if (('A' <= c) && (c <= 'F'))
      return (byte) ((byte) c - (byte) 'A' + 10);
    else
      return -1;
  }
}

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