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 *
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   7 * in the Software without restriction, including  without limitation the rights
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  10 * furnished to do so, subject to the following conditions:
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  12 * The above copyright notice and this permission notice shall be included in
  13 * all copies or substantial portions of the Software.
  14 *
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  17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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  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         [CLSCompliantAttribute(true)]
  41         public class Asn1Length
  42         {
  43                 /// <summary> Returns the length of this Asn1Length.</summary>
  44                 virtual public int Length
  45                 {
  46                         get
  47                         {
  48                                 return length;
  49                         }
  50
  51                 }
  52                 /// <summary> Returns the encoded length of this Asn1Length.</summary>
  53                 virtual public int EncodedLength
  54                 {
  55                         get
  56                         {
  57                                 return encodedLength;
  58                         }
  59
  60                 }
  61
  62                 /* Private variables
  63                 */
  64
  65                 private int length;
  66                 private int encodedLength;
  67
  68                 /* Constructors for Asn1Length
  69                 */
  70
  71                 /// <summary> Constructs an empty Asn1Length.  Values are added by calling reset</summary>
  72                 public Asn1Length()
  73                 {
  74                 }
  75                 /// <summary> Constructs an Asn1Length</summary>
  76                 public Asn1Length(int length)
  77                 {
  78                         this.length = length;
  79                 }
  80
  81                 /// <summary> Constructs an Asn1Length object by decoding data from an
  82                 /// input stream.
  83                 ///
  84                 /// </summary>
  85                 /// <param name="in">A byte stream that contains the encoded ASN.1
  86                 ///
  87                 /// </param>
  88                 public Asn1Length(System.IO.Stream in_Renamed)
  89                 {
  90                         int r = in_Renamed.ReadByte();
  91                         encodedLength++;
  92                         if (r == 0x80)
  93                                 length = - 1;
  94                         else if (r < 0x80)
  95                                 length = r;
  96                         else
  97                         {
  98                                 length = 0;
  99                                 for (r = r & 0x7F; r > 0; r--)
 100                                 {
 101                                         int part = in_Renamed.ReadByte();
 102                                         encodedLength++;
 103                                         if (part < 0)
 104                                                 throw new System.IO.EndOfStreamException("BERDecoder: decode: EOF in Asn1Length");
 105                                         length = (length << 8) + part;
 106                                 }
 107                         }
 108                 }
 109
 110                 /// <summary> Resets an Asn1Length object by decoding data from an
 111                 /// input stream.
 112                 ///
 113                 /// Note: this was added for optimization of Asn1.LBERdecoder.decode()
 114                 ///
 115                 /// </summary>
 116                 /// <param name="in">A byte stream that contains the encoded ASN.1
 117                 ///
 118                 /// </param>
 119                 public void  reset(System.IO.Stream in_Renamed)
 120                 {
 121                         encodedLength = 0;
 122                         int r = in_Renamed.ReadByte();
 123                         encodedLength++;
 124                         if (r == 0x80)
 125                                 length = - 1;
 126                         else if (r < 0x80)
 127                                 length = r;
 128                         else
 129                         {
 130                                 length = 0;
 131                                 for (r = r & 0x7F; r > 0; r--)
 132                                 {
 133                                         int part = in_Renamed.ReadByte();
 134                                         encodedLength++;
 135                                         if (part < 0)
 136                                                 throw new System.IO.EndOfStreamException("BERDecoder: decode: EOF in Asn1Length");
 137                                         length = (length << 8) + part;
 138                                 }
 139                         }
 140                 }
 141         }
 142 }