class/I18N/CJK/DbcsEncoding.cs

   1 //
   2 // I18N.CJK.DbcsEncoding
   3 //
   4 // Author:
   5 //   Alan Tam Siu Lung (Tam@SiuLung.com)
   6 //
   7
   8 using System;
   9 using System.Text;
  10 using I18N.Common;
  11
  12 namespace I18N.CJK
  13 {
  14         [Serializable]
  15         internal abstract class DbcsEncoding : MonoEncoding
  16         {
  17                 public DbcsEncoding (int codePage) : this (codePage, 0)
  18                 {
  19                 }
  20
  21                 public DbcsEncoding (int codePage, int windowsCodePage)
  22                         : base (codePage, windowsCodePage)
  23                 {
  24                 }
  25
  26                 internal abstract DbcsConvert GetConvert ();
  27
  28                 // Get the number of bytes needed to encode a character buffer.
  29                 public override int GetByteCount(char[] chars, int index, int count)
  30                 {
  31                         if (chars == null)
  32                                 throw new ArgumentNullException("chars");
  33                         if (index < 0 || index > chars.Length)
  34                                 throw new ArgumentOutOfRangeException("index", Strings.GetString("ArgRange_Array"));
  35                         if (count < 0 || index + count > chars.Length)
  36                                 throw new ArgumentOutOfRangeException("count", Strings.GetString("ArgRange_Array"));
  37                         byte[] buffer = new byte[count * 2];
  38                         return GetBytes(chars, index, count, buffer, 0);
  39                 }
  40
  41 /*
  42                 // Get the bytes that result from encoding a character buffer.
  43                 public override int GetBytes(char[] chars, int charIndex, int charCount,
  44                                              byte[] bytes, int byteIndex)
  45                 {
  46                         if (chars == null)
  47                                 throw new ArgumentNullException("chars");
  48                         if (bytes == null)
  49                                 throw new ArgumentNullException("bytes");
  50                         if (charIndex < 0 || charIndex > chars.Length)
  51                                 throw new ArgumentOutOfRangeException("charIndex", Strings.GetString("ArgRange_Array"));
  52                         if (charCount < 0 || charIndex + charCount > chars.Length)
  53                                 throw new ArgumentOutOfRangeException("charCount", Strings.GetString("ArgRange_Array"));
  54                         if (byteIndex < 0 || byteIndex > bytes.Length)
  55                                 throw new ArgumentOutOfRangeException("byteIndex", Strings.GetString("ArgRange_Array"));
  56                         return 0; // For subclasses to implement
  57                 }
  58 */
  59
  60                 // Get the number of characters needed to decode a byte buffer.
  61                 public override int GetCharCount(byte[] bytes, int index, int count)
  62                 {
  63                         if (bytes == null)
  64                                 throw new ArgumentNullException("bytes");
  65                         if (index < 0 || index > bytes.Length)
  66                                 throw new ArgumentOutOfRangeException("index", Strings.GetString("ArgRange_Array"));
  67                         if (count < 0 || index + count > bytes.Length)
  68                                 throw new ArgumentOutOfRangeException("count", Strings.GetString("ArgRange_Array"));
  69                         char[] buffer = new char[count];
  70                         return GetChars(bytes, index, count, buffer, 0);
  71                 }
  72
  73                 // Get the characters that result from decoding a byte buffer.
  74                 public override int GetChars(byte[] bytes, int byteIndex, int byteCount,
  75                                              char[] chars, int charIndex)
  76                 {
  77                         if (bytes == null)
  78                                 throw new ArgumentNullException("bytes");
  79                         if (chars == null)
  80                                 throw new ArgumentNullException("chars");
  81                         if (byteIndex < 0 || byteIndex > bytes.Length)
  82                                 throw new ArgumentOutOfRangeException("byteIndex", Strings.GetString("ArgRange_Array"));
  83                         if (byteCount < 0 || byteIndex + byteCount > bytes.Length)
  84                                 throw new ArgumentOutOfRangeException("byteCount", Strings.GetString("ArgRange_Array"));
  85                         if (charIndex < 0 || charIndex > chars.Length)
  86                                 throw new ArgumentOutOfRangeException("charIndex", Strings.GetString("ArgRange_Array"));
  87                         return 0; // For subclasses to implement
  88                 }
  89
  90                 // Get the maximum number of bytes needed to encode a
  91                 // specified number of characters.
  92                 public override int GetMaxByteCount(int charCount)
  93                 {
  94                         if (charCount < 0)
  95                                 throw new ArgumentOutOfRangeException("charCount", Strings.GetString("ArgRange_NonNegative"));
  96                         return charCount * 2;
  97                 }
  98
  99                 // Get the maximum number of characters needed to decode a
 100                 // specified number of bytes.
 101                 public override int GetMaxCharCount(int byteCount)
 102                 {
 103                         if (byteCount < 0) {
 104                                 throw new ArgumentOutOfRangeException("byteCount", Strings.GetString("ArgRange_NonNegative"));
 105                         }
 106                         return byteCount;
 107                 }
 108
 109                 // Determine if this encoding can be displayed in a Web browser.
 110                 public override bool IsBrowserDisplay
 111                 {
 112                         get { return true; }
 113                 }
 114
 115                 // Determine if this encoding can be saved from a Web browser.
 116                 public override bool IsBrowserSave
 117                 {
 118                         get { return true; }
 119                 }
 120
 121                 // Determine if this encoding can be displayed in a mail/news agent.
 122                 public override bool IsMailNewsDisplay
 123                 {
 124                         get { return true; }
 125                 }
 126
 127                 // Determine if this encoding can be saved from a mail/news agent.
 128                 public override bool IsMailNewsSave
 129                 {
 130                         get { return true; }
 131                 }
 132
 133                 // Decoder that handles a rolling state.
 134                 internal abstract class DbcsDecoder : Decoder
 135                 {
 136                         protected DbcsConvert convert;
 137
 138                         // Constructor.
 139                         public DbcsDecoder(DbcsConvert convert)
 140                         {
 141                                 this.convert = convert;
 142                         }
 143
 144                         internal void CheckRange (byte[] bytes, int index, int count)
 145                         {
 146                                 if (bytes == null)
 147                                         throw new ArgumentNullException("bytes");
 148                                 if (index < 0 || index > bytes.Length)
 149                                         throw new ArgumentOutOfRangeException("index", Strings.GetString("ArgRange_Array"));
 150                                 if (count < 0 || count > (bytes.Length - index))
 151                                         throw new ArgumentOutOfRangeException("count", Strings.GetString("ArgRange_Array"));
 152                         }
 153
 154                         internal void CheckRange (byte[] bytes, int byteIndex, int byteCount,
 155                                                      char[] chars, int charIndex)
 156                         {
 157                                 if (bytes == null)
 158                                         throw new ArgumentNullException("bytes");
 159                                 if (chars == null)
 160                                         throw new ArgumentNullException("chars");
 161                                 if (byteIndex < 0 || byteIndex > bytes.Length)
 162                                         throw new ArgumentOutOfRangeException("byteIndex", Strings.GetString("ArgRange_Array"));
 163                                 if (byteCount < 0 || byteIndex + byteCount > bytes.Length)
 164                                         throw new ArgumentOutOfRangeException("byteCount", Strings.GetString("ArgRange_Array"));
 165                                 if (charIndex < 0 || charIndex > chars.Length)
 166                                         throw new ArgumentOutOfRangeException("charIndex", Strings.GetString("ArgRange_Array"));
 167                         }
 168                 }
 169         }
 170 }