mcs/class/Novell.Directory.Ldap/Novell.Directory.Ldap.Asn1/Asn1Length.cs

   1 /******************************************************************************
   2 * The MIT License
   3 * Copyright (c) 2003 Novell Inc.  www.novell.com
   4 *
   5 * Permission is hereby granted, free of charge, to any person obtaining  a copy
   6 * of this software and associated documentation files (the Software), to deal
   7 * in the Software without restriction, including  without limitation the rights
   8 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9 * copies of the Software, and to  permit persons to whom the Software is
  10 * furnished to do so, subject to the following conditions:
  11 *
  12 * The above copyright notice and this permission notice shall be included in
  13 * all copies or substantial portions of the Software.
  14 *
  15 * THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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  20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21 * SOFTWARE.
  22 *******************************************************************************/
  23 //
  24 // Novell.Directory.Ldap.Asn1.Asn1Length.cs
  25 //
  26 // Author:
  27 //   Sunil Kumar (Sunilk@novell.com)
  28 //
  29 // (C) 2003 Novell, Inc (http://www.novell.com)
  30 //
  31
  32 using System;
  33
  34 namespace Novell.Directory.Ldap.Asn1
  35 {
  36
  37         /// <summary> This class provides a means to manipulate ASN.1 Length's. It will
  38         /// be used by Asn1Encoder's and Asn1Decoder's by composition.
  39         /// </summary>
  40         public class Asn1Length
  41         {
  42                 /// <summary> Returns the length of this Asn1Length.</summary>
  43                 virtual public int Length
  44                 {
  45                         get
  46                         {
  47                                 return length;
  48                         }
  49
  50                 }
  51                 /// <summary> Returns the encoded length of this Asn1Length.</summary>
  52                 virtual public int EncodedLength
  53                 {
  54                         get
  55                         {
  56                                 return encodedLength;
  57                         }
  58
  59                 }
  60
  61                 /* Private variables
  62                 */
  63
  64                 private int length;
  65                 private int encodedLength;
  66
  67                 /* Constructors for Asn1Length
  68                 */
  69
  70                 /// <summary> Constructs an empty Asn1Length.  Values are added by calling reset</summary>
  71                 public Asn1Length()
  72                 {
  73                 }
  74                 /// <summary> Constructs an Asn1Length</summary>
  75                 public Asn1Length(int length)
  76                 {
  77                         this.length = length;
  78                 }
  79
  80                 /// <summary> Constructs an Asn1Length object by decoding data from an
  81                 /// input stream.
  82                 ///
  83                 /// </summary>
  84                 /// <param name="in">A byte stream that contains the encoded ASN.1
  85                 ///
  86                 /// </param>
  87                 public Asn1Length(System.IO.Stream in_Renamed)
  88                 {
  89                         int r = in_Renamed.ReadByte();
  90                         encodedLength++;
  91                         if (r == 0x80)
  92                                 length = - 1;
  93                         else if (r < 0x80)
  94                                 length = r;
  95                         else
  96                         {
  97                                 length = 0;
  98                                 for (r = r & 0x7F; r > 0; r--)
  99                                 {
 100                                         int part = in_Renamed.ReadByte();
 101                                         encodedLength++;
 102                                         if (part < 0)
 103                                                 throw new System.IO.EndOfStreamException("BERDecoder: decode: EOF in Asn1Length");
 104                                         length = (length << 8) + part;
 105                                 }
 106                         }
 107                 }
 108
 109                 /// <summary> Resets an Asn1Length object by decoding data from an
 110                 /// input stream.
 111                 ///
 112                 /// Note: this was added for optimization of Asn1.LBERdecoder.decode()
 113                 ///
 114                 /// </summary>
 115                 /// <param name="in">A byte stream that contains the encoded ASN.1
 116                 ///
 117                 /// </param>
 118                 public void  reset(System.IO.Stream in_Renamed)
 119                 {
 120                         encodedLength = 0;
 121                         int r = in_Renamed.ReadByte();
 122                         encodedLength++;
 123                         if (r == 0x80)
 124                                 length = - 1;
 125                         else if (r < 0x80)
 126                                 length = r;
 127                         else
 128                         {
 129                                 length = 0;
 130                                 for (r = r & 0x7F; r > 0; r--)
 131                                 {
 132                                         int part = in_Renamed.ReadByte();
 133                                         encodedLength++;
 134                                         if (part < 0)
 135                                                 throw new System.IO.EndOfStreamException("BERDecoder: decode: EOF in Asn1Length");
 136                                         length = (length << 8) + part;
 137                                 }
 138                         }
 139                 }
 140         }
 141 }