Source for gnu.java.security.x509.Util

   1: /* Util.java -- Miscellaneous utility methods.
   2:    Copyright (C) 2004, 2006  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package gnu.java.security.x509;
  40: 
  41: /**
  42:  * A collection of useful class methods.
  43:  *
  44:  * @author Casey Marshall (rsdio@metastatic.org)
  45:  */
  46: public final class Util
  47: {
  48: 
  49:   // Constants.
  50:   // -------------------------------------------------------------------------
  51: 
  52:   public static final String HEX = "0123456789abcdef";
  53: 
  54:   // Class methods.
  55:   // -------------------------------------------------------------------------
  56: 
  57:   /**
  58:    * Convert a byte array to a hexadecimal string, as though it were a
  59:    * big-endian arbitrarily-sized integer.
  60:    *
  61:    * @param buf The bytes to format.
  62:    * @param off The offset to start at.
  63:    * @param len The number of bytes to format.
  64:    * @return A hexadecimal representation of the specified bytes.
  65:    */
  66:   public static String toHexString(byte[] buf, int off, int len)
  67:   {
  68:     StringBuffer str = new StringBuffer();
  69:     for (int i = 0; i < len; i++)
  70:       {
  71:         str.append(HEX.charAt(buf[i+off] >>> 4 & 0x0F));
  72:         str.append(HEX.charAt(buf[i+off] & 0x0F));
  73:       }
  74:     return str.toString();
  75:   }
  76: 
  77:   /**
  78:    * See {@link #toHexString(byte[],int,int)}.
  79:    */
  80:   public static String toHexString(byte[] buf)
  81:   {
  82:     return Util.toHexString(buf, 0, buf.length);
  83:   }
  84: 
  85:   /**
  86:    * Convert a byte array to a hexadecimal string, separating octets
  87:    * with the given character.
  88:    *
  89:    * @param buf The bytes to format.
  90:    * @param off The offset to start at.
  91:    * @param len The number of bytes to format.
  92:    * @param sep The character to insert between octets.
  93:    * @return A hexadecimal representation of the specified bytes.
  94:    */
  95:   public static String toHexString(byte[] buf, int off, int len, char sep)
  96:   {
  97:     StringBuffer str = new StringBuffer();
  98:     for (int i = 0; i < len; i++)
  99:       {
 100:         str.append(HEX.charAt(buf[i+off] >>> 4 & 0x0F));
 101:         str.append(HEX.charAt(buf[i+off] & 0x0F));
 102:         if (i < len - 1)
 103:           str.append(sep);
 104:       }
 105:     return str.toString();
 106:   }
 107: 
 108:   /**
 109:    * See {@link #toHexString(byte[],int,int,char)}.
 110:    */
 111:   public static String toHexString(byte[] buf, char sep)
 112:   {
 113:     return Util.toHexString(buf, 0, buf.length, sep);
 114:   }
 115: 
 116:   /**
 117:    * Create a representation of the given byte array similar to the
 118:    * output of `hexdump -C', which is
 119:    *
 120:    * <p><pre>OFFSET  SIXTEEN-BYTES-IN-HEX  PRINTABLE-BYTES</pre>
 121:    *
 122:    * <p>The printable bytes show up as-is if they are printable and
 123:    * not a newline character, otherwise showing as '.'.
 124:    *
 125:    * @param buf The bytes to format.
 126:    * @param off The offset to start at.
 127:    * @param len The number of bytes to encode.
 128:    * @return The formatted string.
 129:    */
 130:   public static String hexDump(byte[] buf, int off, int len, String prefix)
 131:   {
 132:     String nl = System.getProperty("line.separator");
 133:     StringBuffer str = new StringBuffer();
 134:     int i = 0;
 135:     while (i < len)
 136:       {
 137:         str.append(prefix);
 138:         str.append(Util.formatInt(i+off, 16, 8));
 139:         str.append("  ");
 140:         String s = Util.toHexString(buf, i+off, Math.min(16, len-i), ' ');
 141:         str.append(s);
 142:         for (int j = 56 - (56 - s.length()); j < 56; j++)
 143:           str.append(" ");
 144:         for (int j = 0; j < Math.min(16, len - i); j++)
 145:           {
 146:             if ((buf[i+off+j] & 0xFF) < 0x20 || (buf[i+off+j] & 0xFF) > 0x7E)
 147:               str.append('.');
 148:             else
 149:               str.append((char) (buf[i+off+j] & 0xFF));
 150:           }
 151:         str.append(nl);
 152:         i += 16;
 153:       }
 154:     return str.toString();
 155:   }
 156: 
 157:   /**
 158:    * See {@link #hexDump(byte[],int,int,String)}.
 159:    */
 160:   public static String hexDump(byte[] buf, String prefix)
 161:   {
 162:     return hexDump(buf, 0, buf.length, prefix);
 163:   }
 164: 
 165:   /**
 166:    * Format an integer into the specified radix, zero-filled.
 167:    *
 168:    * @param i The integer to format.
 169:    * @param radix The radix to encode to.
 170:    * @param len The target length of the string. The string is
 171:    *   zero-padded to this length, but may be longer.
 172:    * @return The formatted integer.
 173:    */
 174:   public static String formatInt(int i, int radix, int len)
 175:   {
 176:     String s = Integer.toString(i, radix);
 177:     StringBuffer buf = new StringBuffer();
 178:     for (int j = 0; j < len - s.length(); j++)
 179:       buf.append("0");
 180:     buf.append(s);
 181:     return buf.toString();
 182:   }
 183: 
 184:   /**
 185:    * Convert a hexadecimal string into its byte representation.
 186:    *
 187:    * @param hex The hexadecimal string.
 188:    * @return The converted bytes.
 189:    */
 190:   public static byte[] toByteArray(String hex)
 191:   {
 192:     hex = hex.toLowerCase();
 193:     byte[] buf = new byte[hex.length() / 2];
 194:     int j = 0;
 195:     for (int i = 0; i < buf.length; i++)
 196:       {
 197:         buf[i] = (byte) ((Character.digit(hex.charAt(j++), 16) << 4) |
 198:                           Character.digit(hex.charAt(j++), 16));
 199:       }
 200:     return buf;
 201:   }
 202: }