class/corlib/System.Text/Encoder.cs

   1 /*
   2  * Encoder.cs - Implementation of the "System.Text.Encoder" class.
   3  *
   4  * Copyright (c) 2001  Southern Storm Software, Pty Ltd
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining
   7  * a copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 namespace System.Text
  26 {
  27
  28 using System;
  29 using System.Runtime.InteropServices;
  30
  31 [Serializable]
  32 [ComVisible (true)]
  33 public abstract class Encoder
  34 {
  35
  36         // Constructor.
  37         protected Encoder() {}
  38
  39         EncoderFallback fallback = new EncoderReplacementFallback ();
  40         EncoderFallbackBuffer fallback_buffer;
  41
  42         [ComVisible (false)]
  43         public EncoderFallback Fallback {
  44                 get { return fallback; }
  45                 set {
  46                         if (value == null)
  47                                 throw new ArgumentNullException ();
  48                         fallback = value;
  49                         fallback_buffer = null;
  50                 }
  51         }
  52
  53         [ComVisible (false)]
  54         public EncoderFallbackBuffer FallbackBuffer {
  55                 get {
  56                         if (fallback_buffer == null)
  57                                 fallback_buffer = Fallback.CreateFallbackBuffer ();
  58                         return fallback_buffer;
  59                 }
  60         }
  61
  62         // Get the number of bytes needed to encode a buffer.
  63         public abstract int GetByteCount(char[] chars, int index,
  64                                                                          int count, bool flush);
  65
  66         // Get the bytes that result from decoding a buffer.
  67         public abstract int GetBytes(char[] chars, int charIndex, int charCount,
  68                                                                  byte[] bytes, int byteIndex, bool flush);
  69
  70         [CLSCompliant (false)]
  71         [ComVisible (false)]
  72         public unsafe virtual int GetByteCount (char* chars, int count, bool flush)
  73         {
  74                 if (chars == null)
  75                         throw new ArgumentNullException ("chars");
  76                 if (count < 0)
  77                         throw new ArgumentOutOfRangeException ("count");
  78
  79                 char [] carr = new char [count];
  80                 Marshal.Copy ((IntPtr) chars, carr, 0, count);
  81                 return GetByteCount (carr, 0, count, flush);
  82         }
  83
  84         [CLSCompliant (false)]
  85         [ComVisible (false)]
  86         public unsafe virtual int GetBytes (char* chars, int charCount,
  87                 byte* bytes, int byteCount, bool flush)
  88         {
  89                 CheckArguments (chars, charCount, bytes, byteCount);
  90
  91                 char [] carr = new char [charCount];
  92                 Marshal.Copy ((IntPtr) chars, carr, 0, charCount);
  93                 byte [] barr = new byte [byteCount];
  94                 Marshal.Copy ((IntPtr) bytes, barr, 0, byteCount);
  95                 return GetBytes (carr, 0, charCount, barr, 0, flush);
  96         }
  97
  98         [ComVisible (false)]
  99         public virtual void Reset ()
 100         {
 101                 if (fallback_buffer != null)
 102                         fallback_buffer.Reset ();
 103         }
 104
 105         [CLSCompliant (false)]
 106         [ComVisible (false)]
 107         public unsafe virtual void Convert (
 108                 char* chars, int charCount,
 109                 byte* bytes, int byteCount, bool flush,
 110                 out int charsUsed, out int bytesUsed, out bool completed)
 111         {
 112                 CheckArguments (chars, charCount, bytes, byteCount);
 113
 114                 charsUsed = charCount;
 115                 while (true) {
 116                         bytesUsed = GetByteCount (chars, charsUsed, flush);
 117                         if (bytesUsed <= byteCount)
 118                                 break;
 119                         flush = false;
 120                         charsUsed >>= 1;
 121                 }
 122                 completed = charsUsed == charCount;
 123                 bytesUsed = GetBytes (chars, charsUsed, bytes, byteCount, flush);
 124         }
 125
 126         [ComVisible (false)]
 127         public virtual void Convert (
 128                 char [] chars, int charIndex, int charCount,
 129                 byte [] bytes, int byteIndex, int byteCount, bool flush,
 130                 out int charsUsed, out int bytesUsed, out bool completed)
 131         {
 132                 if (chars == null)
 133                         throw new ArgumentNullException ("chars");
 134                 if (bytes == null)
 135                         throw new ArgumentNullException ("bytes");
 136                 if (charIndex < 0 || chars.Length <= charIndex)
 137                         throw new ArgumentOutOfRangeException ("charIndex");
 138                 if (charCount < 0 || chars.Length < charIndex + charCount)
 139                         throw new ArgumentOutOfRangeException ("charCount");
 140                 if (byteIndex < 0 || bytes.Length <= byteIndex)
 141                         throw new ArgumentOutOfRangeException ("byteIndex");
 142                 if (byteCount < 0 || bytes.Length < byteIndex + byteCount)
 143                         throw new ArgumentOutOfRangeException ("byteCount");
 144
 145                 charsUsed = charCount;
 146                 while (true) {
 147                         bytesUsed = GetByteCount (chars, charIndex, charsUsed, flush);
 148                         if (bytesUsed <= byteCount)
 149                                 break;
 150                         flush = false;
 151                         charsUsed >>= 1;
 152                 }
 153                 completed = charsUsed == charCount;
 154                 bytesUsed = GetBytes (chars, charIndex, charsUsed, bytes, byteIndex, flush);
 155         }
 156
 157         unsafe void CheckArguments (char* chars, int charCount, byte* bytes, int byteCount)
 158         {
 159                 if (chars == null)
 160                         throw new ArgumentNullException ("chars");
 161                 if (bytes == null)
 162                         throw new ArgumentNullException ("bytes");
 163                 if (charCount < 0)
 164                         throw new ArgumentOutOfRangeException ("charCount");
 165                 if (byteCount < 0)
 166                         throw new ArgumentOutOfRangeException ("byteCount");
 167         }
 168 }; // class Encoder
 169
 170 }; // namespace System.Text