mcs/class/corlib/System.IO/BinaryReader.cs

   1 //
   2 // System.IO.BinaryReader
   3 //
   4 // Author:
   5 //   Matt Kimball (matt@kimball.net)
   6 //   Dick Porter (dick@ximian.com)
   7 //
   8
   9 //
  10 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System;
  33 using System.Text;
  34 using System.Globalization;
  35
  36 namespace System.IO {
  37         public class BinaryReader : IDisposable {
  38                 Stream m_stream;
  39                 Encoding m_encoding;
  40                 int m_encoding_max_byte;
  41
  42                 byte[] m_buffer;
  43
  44                 private bool m_disposed = false;
  45
  46                 public BinaryReader(Stream input) : this(input, Encoding.UTF8Unmarked) {
  47                 }
  48
  49                 public BinaryReader(Stream input, Encoding encoding) {
  50                         if (input == null || encoding == null)
  51                                 throw new ArgumentNullException(Locale.GetText ("Input or Encoding is a null reference."));
  52                         if (!input.CanRead)
  53                                 throw new ArgumentException(Locale.GetText ("The stream doesn't support reading."));
  54
  55                         m_stream = input;
  56                         m_encoding = encoding;
  57                         m_encoding_max_byte = m_encoding.GetMaxByteCount(1);
  58                         m_buffer = new byte [32];
  59                 }
  60
  61                 public virtual Stream BaseStream {
  62                         get {
  63                                 return m_stream;
  64                         }
  65                 }
  66
  67                 public virtual void Close() {
  68                         Dispose (true);
  69                         m_disposed = true;
  70                 }
  71
  72                 protected virtual void Dispose (bool disposing)
  73                 {
  74                         if (disposing && m_stream != null)
  75                                 m_stream.Close ();
  76
  77                         m_disposed = true;
  78                         m_buffer = null;
  79                         m_encoding = null;
  80                         m_stream = null;
  81                 }
  82
  83                 void IDisposable.Dispose()
  84                 {
  85                         Dispose (true);
  86                 }
  87
  88                 protected virtual void FillBuffer (int bytes)
  89                 {
  90                         if (m_disposed)
  91                                 throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
  92                         if (m_stream==null)
  93                                 throw new IOException("Stream is invalid");
  94
  95                         CheckBuffer(bytes);
  96
  97                         /* Cope with partial reads */
  98                         int pos=0;
  99
 100                         while(pos<bytes) {
 101                                 int n=m_stream.Read(m_buffer, pos, bytes-pos);
 102                                 if(n==0) {
 103                                         throw new EndOfStreamException();
 104                                 }
 105
 106                                 pos+=n;
 107                         }
 108                 }
 109
 110                 public virtual int PeekChar() {
 111                         if(m_stream==null) {
 112
 113                                 if (m_disposed)
 114                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 115
 116                                 throw new IOException("Stream is invalid");
 117                         }
 118
 119                         if ( !m_stream.CanSeek )
 120                         {
 121                                 return -1;
 122                         }
 123
 124                         char[] result = new char[1];
 125                         byte[] bytes;
 126                         int bcount;
 127
 128                         int ccount = ReadCharBytes (result, 0, 1, out bytes, out bcount);
 129
 130                         // Reposition the stream
 131                         m_stream.Position -= bcount;
 132
 133                         // If we read 0 characters then return -1
 134                         if (ccount == 0)
 135                         {
 136                                 return -1;
 137                         }
 138
 139                         // Return the single character we read
 140                         return result[0];
 141                 }
 142
 143                 public virtual int Read() {
 144                         char[] decode = new char[1];
 145
 146                         int count=Read(decode, 0, 1);
 147                         if(count==0) {
 148                                 /* No chars available */
 149                                 return(-1);
 150                         }
 151
 152                         return decode[0];
 153                 }
 154
 155                 public virtual int Read(byte[] buffer, int index, int count) {
 156                         if(m_stream==null) {
 157
 158                                 if (m_disposed)
 159                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 160
 161                                 throw new IOException("Stream is invalid");
 162                         }
 163
 164                         if (buffer == null) {
 165                                 throw new ArgumentNullException("buffer is null");
 166                         }
 167                         if (index < 0) {
 168                                 throw new ArgumentOutOfRangeException("index is less than 0");
 169                         }
 170                         if (count < 0) {
 171                                 throw new ArgumentOutOfRangeException("count is less than 0");
 172                         }
 173                         if (buffer.Length - index < count) {
 174                                 throw new ArgumentException("buffer is too small");
 175                         }
 176
 177                         int bytes_read=m_stream.Read(buffer, index, count);
 178
 179                         return(bytes_read);
 180                 }
 181
 182                 public virtual int Read(char[] buffer, int index, int count) {
 183
 184                         if(m_stream==null) {
 185
 186                                 if (m_disposed)
 187                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 188
 189                                 throw new IOException("Stream is invalid");
 190                         }
 191
 192                         if (buffer == null) {
 193                                 throw new ArgumentNullException("buffer is null");
 194                         }
 195                         if (index < 0) {
 196                                 throw new ArgumentOutOfRangeException("index is less than 0");
 197                         }
 198                         if (count < 0) {
 199                                 throw new ArgumentOutOfRangeException("count is less than 0");
 200                         }
 201                         if (buffer.Length - index < count) {
 202                                 throw new ArgumentException("buffer is too small");
 203                         }
 204
 205                         int bytes_read;
 206                         byte[] bytes;
 207                         return ReadCharBytes (buffer, index, count, out bytes, out bytes_read);
 208                 }
 209
 210                 private int ReadCharBytes(char[] buffer, int index, int count, out byte[] bytes, out int bytes_read)
 211                 {
 212                         int chars_read=0;
 213                         bytes_read=0;
 214
 215                         while(chars_read < count)
 216                         {
 217                                 CheckBuffer(bytes_read + 1);
 218
 219                                 int read_byte = m_stream.ReadByte();
 220
 221                                 if(read_byte==-1)
 222                                 {
 223                                         /* EOF */
 224                                         bytes = m_buffer;
 225                                         return(chars_read);
 226                                 }
 227
 228                                 m_buffer[bytes_read]=(byte)read_byte;
 229                                 bytes_read++;
 230
 231                                 chars_read=m_encoding.GetChars(m_buffer, 0,
 232                                                                                  bytes_read,
 233                                                                                  buffer, index);
 234
 235                         }
 236
 237                         bytes = m_buffer;
 238                         return(chars_read);
 239                 }
 240
 241                 protected int Read7BitEncodedInt() {
 242                         int ret = 0;
 243                         int shift = 0;
 244                         byte b;
 245
 246                         do {
 247                                 b = ReadByte();
 248
 249                                 ret = ret | ((b & 0x7f) << shift);
 250                                 shift += 7;
 251                         } while ((b & 0x80) == 0x80);
 252
 253                         return ret;
 254                 }
 255
 256                 public virtual bool ReadBoolean() {
 257                         // Return value:
 258                         //  true if the byte is non-zero; otherwise false.
 259                         return ReadByte() != 0;
 260                 }
 261
 262                 public virtual byte ReadByte() {
 263                         int val = m_stream.ReadByte ();
 264                         if (val != -1)
 265                                 return (byte) val;
 266
 267                         throw new EndOfStreamException ();
 268                 }
 269
 270                 public virtual byte[] ReadBytes(int count) {
 271                         if(m_stream==null) {
 272
 273                                 if (m_disposed)
 274                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 275
 276                                 throw new IOException("Stream is invalid");
 277                         }
 278
 279                         if (count < 0) {
 280                                 throw new ArgumentOutOfRangeException("count is less than 0");
 281                         }
 282
 283                         /* Can't use FillBuffer() here, because it's OK to
 284                          * return fewer bytes than were requested
 285                          */
 286
 287                         byte[] buf = new byte[count];
 288                         int pos=0;
 289
 290                         while(pos < count)
 291                         {
 292                                 int n=m_stream.Read(buf, pos, count-pos);
 293                                 if(n==0) {
 294                                         /* EOF */
 295                                         break;
 296                                 }
 297
 298                                 pos+=n;
 299                         }
 300
 301                         if (pos!=count) {
 302                                 byte[] new_buffer=new byte[pos];
 303                                 Array.Copy(buf, new_buffer, pos);
 304                                 return(new_buffer);
 305                         }
 306
 307                         return(buf);
 308                 }
 309
 310                 public virtual char ReadChar() {
 311                         int ch=Read();
 312
 313                         if(ch==-1) {
 314                                 throw new EndOfStreamException();
 315                         }
 316
 317                         return((char)ch);
 318                 }
 319
 320                 public virtual char[] ReadChars(int count) {
 321                         if (count < 0) {
 322                                 throw new ArgumentOutOfRangeException("count is less than 0");
 323                         }
 324
 325                         char[] full = new char[count];
 326                         int chars = Read(full, 0, count);
 327
 328                         if (chars == 0) {
 329                                 throw new EndOfStreamException();
 330                         } else if (chars != full.Length) {
 331                                 char[] ret = new char[chars];
 332                                 Array.Copy(full, 0, ret, 0, chars);
 333                                 return ret;
 334                         } else {
 335                                 return full;
 336                         }
 337                 }
 338
 339                 unsafe public virtual decimal ReadDecimal() {
 340                         FillBuffer(16);
 341
 342                         decimal ret;
 343                         byte* ret_ptr = (byte *)&ret;
 344                         for (int i = 0; i < 16; i++) {
 345
 346                                 /*
 347                                  * internal representation of decimal is
 348                                  * ss32, hi32, lo32, mi32,
 349                                  * but in stream it is
 350                                  * lo32, mi32, hi32, ss32
 351                                  * So we have to rerange this int32 values
 352                                  */
 353
 354                                 if (i < 4) {
 355                                         // lo 8 - 12
 356                                         ret_ptr [i + 8] = m_buffer [i];
 357                                 } else if (i < 8) {
 358                                         // mid 12 - 16
 359                                         ret_ptr [i + 8] = m_buffer [i];
 360                                 } else if (i < 12) {
 361                                         // hi 4 - 8
 362                                         ret_ptr [i - 4] = m_buffer [i];
 363                                 } else if (i < 16) {
 364                                         // ss 0 - 4
 365                                         ret_ptr [i - 12] = m_buffer [i];
 366                                 }
 367                         }
 368
 369                         return ret;
 370                 }
 371
 372                 public virtual double ReadDouble() {
 373                         FillBuffer(8);
 374
 375                         return(BitConverter.ToDouble(m_buffer, 0));
 376                 }
 377
 378                 public virtual short ReadInt16() {
 379                         FillBuffer(2);
 380
 381                         return((short) (m_buffer[0] | (m_buffer[1] << 8)));
 382                 }
 383
 384                 public virtual int ReadInt32() {
 385                         FillBuffer(4);
 386
 387                         return(m_buffer[0] | (m_buffer[1] << 8) |
 388                                (m_buffer[2] << 16) | (m_buffer[3] << 24));
 389                 }
 390
 391                 public virtual long ReadInt64() {
 392                         FillBuffer(8);
 393
 394                         uint ret_low  = (uint) (m_buffer[0]            |
 395                                                (m_buffer[1] << 8)  |
 396                                                (m_buffer[2] << 16) |
 397                                                (m_buffer[3] << 24)
 398                                                );
 399                         uint ret_high = (uint) (m_buffer[4]        |
 400                                                (m_buffer[5] << 8)  |
 401                                                (m_buffer[6] << 16) |
 402                                                (m_buffer[7] << 24)
 403                                                );
 404                         return (long) ((((ulong) ret_high) << 32) | ret_low);
 405                 }
 406
 407                 [CLSCompliant(false)]
 408                 public virtual sbyte ReadSByte() {
 409                         return (sbyte) ReadByte ();
 410                 }
 411
 412                 public virtual string ReadString() {
 413                         /* Inspection of BinaryWriter-written files
 414                          * shows that the length is given in bytes,
 415                          * not chars
 416                          */
 417                         int len = Read7BitEncodedInt();
 418
 419                         FillBuffer(len);
 420
 421                         char[] str = m_encoding.GetChars(m_buffer, 0, len);
 422
 423                         return(new String(str));
 424                 }
 425
 426                 public virtual float ReadSingle() {
 427                         FillBuffer(4);
 428
 429                         return(BitConverter.ToSingle(m_buffer, 0));
 430                 }
 431
 432                 [CLSCompliant(false)]
 433                 public virtual ushort ReadUInt16() {
 434                         FillBuffer(2);
 435
 436                         return((ushort) (m_buffer[0] | (m_buffer[1] << 8)));
 437                 }
 438
 439                 [CLSCompliant(false)]
 440                 public virtual uint ReadUInt32() {
 441                         FillBuffer(4);
 442
 443
 444                         return((uint) (m_buffer[0] |
 445                                        (m_buffer[1] << 8) |
 446                                        (m_buffer[2] << 16) |
 447                                        (m_buffer[3] << 24)));
 448                 }
 449
 450                 [CLSCompliant(false)]
 451                 public virtual ulong ReadUInt64() {
 452                         FillBuffer(8);
 453
 454                         uint ret_low  = (uint) (m_buffer[0]            |
 455                                                (m_buffer[1] << 8)  |
 456                                                (m_buffer[2] << 16) |
 457                                                (m_buffer[3] << 24)
 458                                                );
 459                         uint ret_high = (uint) (m_buffer[4]        |
 460                                                (m_buffer[5] << 8)  |
 461                                                (m_buffer[6] << 16) |
 462                                                (m_buffer[7] << 24)
 463                                                );
 464                         return (((ulong) ret_high) << 32) | ret_low;
 465                 }
 466
 467                 /* Ensures that m_buffer is at least length bytes
 468                  * long, growing it if necessary
 469                  */
 470                 private void CheckBuffer(int length)
 471                 {
 472                         if(m_buffer.Length <= length) {
 473                                 byte[] new_buffer=new byte[length];
 474                                 Array.Copy(m_buffer, new_buffer,
 475                                            m_buffer.Length);
 476                                 m_buffer=new_buffer;
 477                         }
 478                 }
 479         }
 480 }