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 using Mono.Security;
  36
  37 namespace System.IO {
  38         public class BinaryReader : IDisposable {
  39                 Stream m_stream;
  40                 Encoding m_encoding;
  41                 int m_encoding_max_byte;
  42
  43                 byte[] m_buffer;
  44
  45                 Decoder decoder;
  46                 char [] charBuffer;
  47
  48                 //
  49                 // 128 chars should cover most strings in one grab.
  50                 //
  51                 const int MaxBufferSize = 128;
  52
  53
  54                 private bool m_disposed = false;
  55
  56                 public BinaryReader(Stream input) : this(input, Encoding.UTF8Unmarked) {
  57                 }
  58
  59                 public BinaryReader(Stream input, Encoding encoding) {
  60                         if (input == null || encoding == null)
  61                                 throw new ArgumentNullException(Locale.GetText ("Input or Encoding is a null reference."));
  62                         if (!input.CanRead)
  63                                 throw new ArgumentException(Locale.GetText ("The stream doesn't support reading."));
  64
  65                         m_stream = input;
  66                         m_encoding = encoding;
  67                         decoder = encoding.GetDecoder ();
  68                         m_buffer = new byte [32];
  69                 }
  70
  71                 public virtual Stream BaseStream {
  72                         get {
  73                                 return m_stream;
  74                         }
  75                 }
  76
  77                 public virtual void Close() {
  78                         Dispose (true);
  79                         m_disposed = true;
  80                 }
  81
  82                 protected virtual void Dispose (bool disposing)
  83                 {
  84                         if (disposing && m_stream != null)
  85                                 m_stream.Close ();
  86
  87                         m_disposed = true;
  88                         m_buffer = null;
  89                         m_encoding = null;
  90                         m_stream = null;
  91                         charBuffer = null;
  92                 }
  93
  94                 void IDisposable.Dispose()
  95                 {
  96                         Dispose (true);
  97                 }
  98
  99                 protected virtual void FillBuffer (int bytes)
 100                 {
 101                         if (m_disposed)
 102                                 throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 103                         if (m_stream==null)
 104                                 throw new IOException("Stream is invalid");
 105
 106                         CheckBuffer(bytes);
 107
 108                         /* Cope with partial reads */
 109                         int pos=0;
 110
 111                         while(pos<bytes) {
 112                                 int n=m_stream.Read(m_buffer, pos, bytes-pos);
 113                                 if(n==0) {
 114                                         throw new EndOfStreamException();
 115                                 }
 116
 117                                 pos+=n;
 118                         }
 119                 }
 120
 121                 public virtual int PeekChar() {
 122                         if(m_stream==null) {
 123
 124                                 if (m_disposed)
 125                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 126
 127                                 throw new IOException("Stream is invalid");
 128                         }
 129
 130                         if ( !m_stream.CanSeek )
 131                         {
 132                                 return -1;
 133                         }
 134
 135                         char[] result = new char[1];
 136                         byte[] bytes;
 137                         int bcount;
 138
 139                         int ccount = ReadCharBytes (result, 0, 1, out bytes, out bcount);
 140
 141                         // Reposition the stream
 142                         m_stream.Position -= bcount;
 143
 144                         // If we read 0 characters then return -1
 145                         if (ccount == 0)
 146                         {
 147                                 return -1;
 148                         }
 149
 150                         // Return the single character we read
 151                         return result[0];
 152                 }
 153
 154                 public virtual int Read() {
 155                         if (charBuffer == null)
 156                                 charBuffer = new char [MaxBufferSize];
 157
 158                         int count = Read (charBuffer, 0, 1);
 159                         if(count == 0) {
 160                                 /* No chars available */
 161                                 return -1;
 162                         }
 163
 164                         return charBuffer [0];
 165                 }
 166
 167                 public virtual int Read(byte[] buffer, int index, int count) {
 168                         if(m_stream==null) {
 169
 170                                 if (m_disposed)
 171                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 172
 173                                 throw new IOException("Stream is invalid");
 174                         }
 175
 176                         if (buffer == null) {
 177                                 throw new ArgumentNullException("buffer is null");
 178                         }
 179                         if (index < 0) {
 180                                 throw new ArgumentOutOfRangeException("index is less than 0");
 181                         }
 182                         if (count < 0) {
 183                                 throw new ArgumentOutOfRangeException("count is less than 0");
 184                         }
 185                         if (buffer.Length - index < count) {
 186                                 throw new ArgumentException("buffer is too small");
 187                         }
 188
 189                         int bytes_read=m_stream.Read(buffer, index, count);
 190
 191                         return(bytes_read);
 192                 }
 193
 194                 public virtual int Read(char[] buffer, int index, int count) {
 195
 196                         if(m_stream==null) {
 197
 198                                 if (m_disposed)
 199                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 200
 201                                 throw new IOException("Stream is invalid");
 202                         }
 203
 204                         if (buffer == null) {
 205                                 throw new ArgumentNullException("buffer is null");
 206                         }
 207                         if (index < 0) {
 208                                 throw new ArgumentOutOfRangeException("index is less than 0");
 209                         }
 210                         if (count < 0) {
 211                                 throw new ArgumentOutOfRangeException("count is less than 0");
 212                         }
 213                         if (buffer.Length - index < count) {
 214                                 throw new ArgumentException("buffer is too small");
 215                         }
 216
 217                         int bytes_read;
 218                         byte[] bytes;
 219                         return ReadCharBytes (buffer, index, count, out bytes, out bytes_read);
 220                 }
 221
 222                 private int ReadCharBytes(char[] buffer, int index, int count, out byte[] bytes, out int bytes_read) \r
 223                 {
 224                         int chars_read=0;
 225                         bytes_read=0;
 226
 227                         while(chars_read < count)
 228                         {
 229                                 CheckBuffer(bytes_read + 1);
 230
 231                                 int read_byte = m_stream.ReadByte();
 232
 233                                 if(read_byte==-1)
 234                                 {
 235                                         /* EOF */
 236                                         bytes = m_buffer;
 237                                         return(chars_read);
 238                                 }
 239
 240                                 m_buffer[bytes_read]=(byte)read_byte;
 241                                 bytes_read++;
 242
 243                                 chars_read=m_encoding.GetChars(m_buffer, 0,
 244                                                                                  bytes_read,
 245                                                                                  buffer, index);
 246
 247                         }
 248
 249                         bytes = m_buffer;
 250                         return(chars_read);
 251                 }
 252
 253                 protected int Read7BitEncodedInt() {
 254                         int ret = 0;
 255                         int shift = 0;
 256                         byte b;
 257
 258                         do {
 259                                 b = ReadByte();
 260
 261                                 ret = ret | ((b & 0x7f) << shift);
 262                                 shift += 7;
 263                         } while ((b & 0x80) == 0x80);
 264
 265                         return ret;
 266                 }
 267
 268                 public virtual bool ReadBoolean() {
 269                         // Return value:
 270                         //  true if the byte is non-zero; otherwise false.
 271                         return ReadByte() != 0;
 272                 }
 273
 274                 public virtual byte ReadByte() {
 275                         if (m_stream == null) {
 276                                 if (m_disposed)
 277                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 278
 279                                 throw new IOException ("Stream is invalid");
 280                         }
 281
 282                         int val = m_stream.ReadByte ();
 283                         if (val != -1)
 284                                 return (byte) val;
 285
 286                         throw new EndOfStreamException ();
 287                 }
 288
 289                 public virtual byte[] ReadBytes(int count) {
 290                         if(m_stream==null) {
 291
 292                                 if (m_disposed)
 293                                         throw new ObjectDisposedException ("BinaryReader", "Cannot read from a closed BinaryReader.");
 294
 295                                 throw new IOException("Stream is invalid");
 296                         }
 297
 298                         if (count < 0) {
 299                                 throw new ArgumentOutOfRangeException("count is less than 0");
 300                         }
 301
 302                         /* Can't use FillBuffer() here, because it's OK to
 303                          * return fewer bytes than were requested
 304                          */
 305
 306                         byte[] buf = new byte[count];
 307                         int pos=0;
 308
 309                         while(pos < count) \r
 310                         {
 311                                 int n=m_stream.Read(buf, pos, count-pos);
 312                                 if(n==0) {
 313                                         /* EOF */
 314                                         break;
 315                                 }
 316
 317                                 pos+=n;
 318                         }
 319
 320                         if (pos!=count) {
 321                                 byte[] new_buffer=new byte[pos];
 322                                 Buffer.BlockCopyInternal (buf, 0, new_buffer, 0, pos);
 323                                 return(new_buffer);
 324                         }
 325
 326                         return(buf);
 327                 }
 328
 329                 public virtual char ReadChar() {
 330                         int ch=Read();
 331
 332                         if(ch==-1) {
 333                                 throw new EndOfStreamException();
 334                         }
 335
 336                         return((char)ch);
 337                 }
 338
 339                 public virtual char[] ReadChars(int count) {
 340                         if (count < 0) {
 341                                 throw new ArgumentOutOfRangeException("count is less than 0");
 342                         }
 343
 344                         if (count == 0)
 345                                 return new char [0];
 346
 347                         char[] full = new char[count];
 348                         int chars = Read(full, 0, count);
 349
 350                         if (chars == 0) {
 351                                 throw new EndOfStreamException();
 352                         } else if (chars != full.Length) {
 353                                 char[] ret = new char[chars];
 354                                 Array.Copy(full, 0, ret, 0, chars);
 355                                 return ret;
 356                         } else {
 357                                 return full;
 358                         }
 359                 }
 360
 361                 unsafe public virtual decimal ReadDecimal() {
 362                         FillBuffer(16);
 363
 364                         decimal ret;
 365                         byte* ret_ptr = (byte *)&ret;
 366
 367                         /*
 368                          * internal representation of decimal is
 369                          * ss32, hi32, lo32, mi32,
 370                          * but in stream it is
 371                          * lo32, mi32, hi32, ss32
 372                          * So we have to rerange this int32 values
 373                          */
 374
 375                         if (BitConverter.IsLittleEndian) {
 376                                 for (int i = 0; i < 16; i++) {
 377                                         if (i < 4) {
 378                                                 // lo 8 - 12
 379                                                 ret_ptr [i + 8] = m_buffer [i];
 380                                         } else if (i < 8) {
 381                                                 // mid 12 - 16
 382                                                 ret_ptr [i + 8] = m_buffer [i];
 383                                         } else if (i < 12) {
 384                                                 // hi 4 - 8
 385                                                 ret_ptr [i - 4] = m_buffer [i];
 386                                         } else if (i < 16) {
 387                                                 // ss 0 - 4
 388                                                 ret_ptr [i - 12] = m_buffer [i];
 389                                         }
 390                                 }
 391                         } else {
 392                                 for (int i = 0; i < 16; i++) {
 393                                         if (i < 4) {
 394                                                 // lo 8 - 12
 395                                                 ret_ptr [11 - i] = m_buffer [i];
 396                                         } else if (i < 8) {
 397                                                 // mid 12 - 16
 398                                                 ret_ptr [19 - i] = m_buffer [i];
 399                                         } else if (i < 12) {
 400                                                 // hi 4 - 8
 401                                                 ret_ptr [15 - i] = m_buffer [i];
 402                                         } else if (i < 16) {
 403                                                 // ss 0 - 4
 404                                                 ret_ptr [15 - i] = m_buffer [i];
 405                                         }
 406                                 }
 407                         }
 408
 409                         return ret;
 410                 }
 411
 412                 public virtual double ReadDouble() {
 413                         FillBuffer(8);
 414
 415                         return(BitConverterLE.ToDouble(m_buffer, 0));
 416                 }
 417
 418                 public virtual short ReadInt16() {
 419                         FillBuffer(2);
 420
 421                         return((short) (m_buffer[0] | (m_buffer[1] << 8)));
 422                 }
 423
 424                 public virtual int ReadInt32() {
 425                         FillBuffer(4);
 426
 427                         return(m_buffer[0] | (m_buffer[1] << 8) |
 428                                (m_buffer[2] << 16) | (m_buffer[3] << 24));
 429                 }
 430
 431                 public virtual long ReadInt64() {
 432                         FillBuffer(8);
 433
 434                         uint ret_low  = (uint) (m_buffer[0]            |
 435                                                (m_buffer[1] << 8)  |
 436                                                (m_buffer[2] << 16) |
 437                                                (m_buffer[3] << 24)
 438                                                );
 439                         uint ret_high = (uint) (m_buffer[4]        |
 440                                                (m_buffer[5] << 8)  |
 441                                                (m_buffer[6] << 16) |
 442                                                (m_buffer[7] << 24)
 443                                                );
 444                         return (long) ((((ulong) ret_high) << 32) | ret_low);
 445                 }
 446
 447                 [CLSCompliant(false)]
 448                 public virtual sbyte ReadSByte() {
 449                         return (sbyte) ReadByte ();
 450                 }
 451
 452                 public virtual string ReadString() {
 453                         /* Inspection of BinaryWriter-written files
 454                          * shows that the length is given in bytes,
 455                          * not chars
 456                          */
 457                         int len = Read7BitEncodedInt();
 458
 459                         if (len < 0)
 460                                 throw new IOException ("Invalid binary file (string len < 0)");
 461
 462                         if (len == 0)
 463                                 return String.Empty;
 464
 465
 466                         if (charBuffer == null)
 467                                 charBuffer = new char [MaxBufferSize];
 468
 469                         //
 470                         // We read the string here in small chunks. Also, we
 471                         // Attempt to optimize the common case of short strings.
 472                         //
 473                         StringBuilder sb = null;
 474                         do {
 475                                 int readLen = (len > MaxBufferSize)
 476                                                 ? MaxBufferSize
 477                                                 : len;
 478
 479                                 FillBuffer (readLen);
 480
 481                                 int cch = decoder.GetChars (m_buffer, 0, readLen, charBuffer, 0);
 482
 483                                 if (sb == null && readLen == len) // ok, we got out the easy way, dont bother with the sb
 484                                         return new String (charBuffer, 0, cch);
 485
 486                                 if (sb == null)
 487                                         // Len is a fairly good estimate of the number of chars in a string
 488                                         // Most of the time 1 byte == 1 char
 489                                         sb = new StringBuilder (len);
 490
 491                                 sb.Append (charBuffer, 0, cch);
 492                                 len -= readLen;
 493                         } while (len > 0);
 494
 495                         return sb.ToString();
 496                 }
 497
 498                 public virtual float ReadSingle() {
 499                         FillBuffer(4);
 500
 501                         return(BitConverterLE.ToSingle(m_buffer, 0));
 502                 }
 503
 504                 [CLSCompliant(false)]
 505                 public virtual ushort ReadUInt16() {
 506                         FillBuffer(2);
 507
 508                         return((ushort) (m_buffer[0] | (m_buffer[1] << 8)));
 509                 }
 510
 511                 [CLSCompliant(false)]
 512                 public virtual uint ReadUInt32() {
 513                         FillBuffer(4);
 514
 515
 516                         return((uint) (m_buffer[0] |
 517                                        (m_buffer[1] << 8) |
 518                                        (m_buffer[2] << 16) |
 519                                        (m_buffer[3] << 24)));
 520                 }
 521
 522                 [CLSCompliant(false)]
 523                 public virtual ulong ReadUInt64() {
 524                         FillBuffer(8);
 525
 526                         uint ret_low  = (uint) (m_buffer[0]            |
 527                                                (m_buffer[1] << 8)  |
 528                                                (m_buffer[2] << 16) |
 529                                                (m_buffer[3] << 24)
 530                                                );
 531                         uint ret_high = (uint) (m_buffer[4]        |
 532                                                (m_buffer[5] << 8)  |
 533                                                (m_buffer[6] << 16) |
 534                                                (m_buffer[7] << 24)
 535                                                );
 536                         return (((ulong) ret_high) << 32) | ret_low;
 537                 }
 538
 539                 /* Ensures that m_buffer is at least length bytes
 540                  * long, growing it if necessary
 541                  */
 542                 private void CheckBuffer(int length)
 543                 {
 544                         if(m_buffer.Length <= length) {
 545                                 byte[] new_buffer=new byte[length];
 546                                 Buffer.BlockCopyInternal (m_buffer, 0, new_buffer, 0, m_buffer.Length);
 547                                 m_buffer=new_buffer;
 548                         }
 549                 }
 550         }
 551 }