mcs/class/System/System.Net/ChunkStream.cs

   1 //
   2 // System.Net.ChunkStream
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //
   7 // (C) 2003 Ximian, Inc (http://www.ximian.com)
   8 //
   9
  10 using System.Collections;
  11 using System.Globalization;
  12 using System.IO;
  13 using System.Text;
  14
  15 namespace System.Net
  16 {
  17         class ChunkStream
  18         {
  19                 enum State {
  20                         None,
  21                         Body,
  22                         BodyFinished,
  23                         Trailer
  24                 }
  25
  26                 class Chunk {
  27                         public byte [] Bytes;
  28                         public int Offset;
  29
  30                         public Chunk (byte [] chunk)
  31                         {
  32                                 this.Bytes = chunk;
  33                         }
  34
  35                         public int Read (byte [] buffer, int offset, int size)
  36                         {
  37                                 int nread = (size > Bytes.Length - Offset) ? Bytes.Length - Offset : size;
  38                                 Buffer.BlockCopy (Bytes, Offset, buffer, offset, nread);
  39                                 Offset += nread;
  40                                 return nread;
  41                         }
  42                 }
  43
  44                 WebHeaderCollection headers;
  45                 int chunkSize;
  46                 int chunkRead;
  47                 State state;
  48                 //byte [] waitBuffer;
  49                 StringBuilder saved;
  50                 bool sawCR;
  51                 bool gotit;
  52                 ArrayList chunks;
  53
  54                 public ChunkStream (byte [] buffer, int offset, int size, WebHeaderCollection headers)
  55                 {
  56                         this.headers = headers;
  57                         saved = new StringBuilder ();
  58                         chunks = new ArrayList ();
  59                         chunkSize = -1;
  60                         Write (buffer, offset, size);
  61                 }
  62
  63                 public void ResetBuffer ()
  64                 {
  65                         chunkSize = -1;
  66                         chunkRead = 0;
  67                         chunks.Clear ();
  68                 }
  69
  70                 public void WriteAndReadBack (byte [] buffer, int offset, int size, ref int read)
  71                 {
  72                         Write (buffer, offset, offset+read);
  73                         read = Read (buffer, offset, size);
  74                 }
  75
  76                 public int Read (byte [] buffer, int offset, int size)
  77                 {
  78                         return ReadFromChunks (buffer, offset, size);
  79                 }
  80
  81                 int ReadFromChunks (byte [] buffer, int offset, int size)
  82                 {
  83                         int count = chunks.Count;
  84                         int nread = 0;
  85                         for (int i = 0; i < count; i++) {
  86                                 Chunk chunk = (Chunk) chunks [i];
  87                                 if (chunk == null)
  88                                         continue;
  89
  90                                 if (chunk.Offset == chunk.Bytes.Length) {
  91                                         chunks [i] = null;
  92                                         continue;
  93                                 }
  94
  95                                 nread += chunk.Read (buffer, offset + nread, size - nread);
  96                                 if (nread == size)
  97                                         break;
  98                         }
  99
 100                         return nread;
 101                 }
 102
 103                 public void Write (byte [] buffer, int offset, int size)
 104                 {
 105                         InternalWrite (buffer, ref offset, size);
 106                 }
 107
 108                 void InternalWrite (byte [] buffer, ref int offset, int size)
 109                 {
 110                         if (state == State.None) {
 111                                 state = GetChunkSize (buffer, ref offset, size);
 112                                 if (state == State.None)
 113                                         return;
 114
 115                                 saved.Length = 0;
 116                                 sawCR = false;
 117                                 gotit = false;
 118                         }
 119
 120                         if (state == State.Body && offset < size) {
 121                                 state = ReadBody (buffer, ref offset, size);
 122                                 if (state == State.Body)
 123                                         return;
 124                         }
 125
 126                         if (state == State.BodyFinished && offset < size) {
 127                                 state = ReadCRLF (buffer, ref offset, size);
 128                                 if (state == State.BodyFinished)
 129                                         return;
 130
 131                                 sawCR = false;
 132                         }
 133
 134                         if (state == State.Trailer && offset < size) {
 135                                 state = ReadTrailer (buffer, ref offset, size);
 136                                 if (state == State.Trailer)
 137                                         return;
 138
 139                                 saved.Length = 0;
 140                                 sawCR = false;
 141                                 gotit = false;
 142                         }
 143
 144                         if (offset < size)
 145                                 InternalWrite (buffer, ref offset, size);
 146                 }
 147
 148                 public bool WantMore {
 149                         get { return (chunkRead != chunkSize || chunkSize != 0); }
 150                 }
 151
 152                 public int ChunkLeft {
 153                         get { return chunkSize - chunkRead; }
 154                 }
 155
 156                 State ReadBody (byte [] buffer, ref int offset, int size)
 157                 {
 158                         if (chunkSize == 0)
 159                                 return State.BodyFinished;
 160
 161                         int diff = size - offset;
 162                         if (diff + chunkRead > chunkSize)
 163                                 diff = chunkSize - chunkRead;
 164
 165                         byte [] chunk = new byte [diff];
 166                         Buffer.BlockCopy (buffer, offset, chunk, 0, diff);
 167                         chunks.Add (new Chunk (chunk));
 168                         offset += diff;
 169                         chunkRead += diff;
 170                         return (chunkRead == chunkSize) ? State.BodyFinished : State.Body;
 171
 172                 }
 173
 174                 State GetChunkSize (byte [] buffer, ref int offset, int size)
 175                 {
 176                         char c = '\0';
 177                         while (offset < size) {
 178                                 c = (char) buffer [offset++];
 179                                 if (c == '\r') {
 180                                         if (sawCR)
 181                                                 throw new ProtocolViolationException ("2 CR found");
 182
 183                                         sawCR = true;
 184                                         continue;
 185                                 }
 186
 187                                 if (sawCR && c == '\n')
 188                                         break;
 189
 190                                 if (c == ' ')
 191                                         gotit = true;
 192
 193                                 if (!gotit)
 194                                         saved.Append (c);
 195                         }
 196
 197                         if (!sawCR || c != '\n')
 198                                 return State.None;
 199
 200                         chunkRead = 0;
 201                         chunkSize = Int32.Parse (saved.ToString (), NumberStyles.HexNumber);
 202                         if (chunkSize == 0)
 203                                 return State.Trailer;
 204
 205                         return State.Body;
 206                 }
 207
 208                 State ReadCRLF (byte [] buffer, ref int offset, int size)
 209                 {
 210                         if (!sawCR) {
 211                                 if ((char) buffer [offset++] != '\r')
 212                                         throw new ProtocolViolationException ("Expecting \\r");
 213
 214                                 sawCR = true;
 215                                 if (offset == size)
 216                                         return State.BodyFinished;
 217                         }
 218
 219                         if ((char) buffer [offset++] != '\n')
 220                                 throw new ProtocolViolationException ("Expecting \\n");
 221
 222                         return State.None;
 223                 }
 224
 225                 State ReadTrailer (byte [] buffer, ref int offset, int size)
 226                 {
 227                         char c = '\0';
 228
 229                         // short path
 230                         if ((char) buffer [offset] == '\r') {
 231                                 offset++;
 232                                 if ((char) buffer [offset] == '\n') {
 233                                         offset++;
 234                                         return State.None;
 235                                 }
 236                                 offset--;
 237                         }
 238
 239                         int st = 0;
 240                         string stString = "\r\n\r";
 241                         while (offset < size && st < 4) {
 242                                 c = (char) buffer [offset++];
 243                                 if ((st == 0 || st == 2) && c == '\r') {
 244                                         st++;
 245                                         continue;
 246                                 }
 247
 248                                 if ((st == 1 || st == 3) && c == '\n') {
 249                                         st++;
 250                                         continue;
 251                                 }
 252
 253                                 if (st > 0) {
 254                                         saved.Append (stString.Substring (0, st));
 255                                         st = 0;
 256                                 }
 257                         }
 258
 259                         if (st < 4)
 260                                 return State.Trailer;
 261
 262                         StringReader reader = new StringReader (saved.ToString ());
 263                         string line;
 264                         while ((line = reader.ReadLine ()) != null && line != "")
 265                                 headers.Add (line);
 266
 267                         return State.None;
 268                 }
 269         }
 270 }
 271