include/wx/stream.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/stream.h
   3 // Purpose:     stream classes
   4 // Author:      Guilhem Lavaux, Guillermo Rodriguez Garcia, Vadim Zeitlin
   5 // Modified by:
   6 // Created:     11/07/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Guilhem Lavaux
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_WXSTREAM_H__
  13 #define _WX_WXSTREAM_H__
  14
  15 #include "wx/defs.h"
  16
  17 #if wxUSE_STREAMS
  18
  19 #include <stdio.h>
  20 #include "wx/object.h"
  21 #include "wx/string.h"
  22 #include "wx/filefn.h"  // for wxFileOffset, wxInvalidOffset and wxSeekMode
  23
  24 class WXDLLIMPEXP_BASE wxStreamBase;
  25 class WXDLLIMPEXP_BASE wxInputStream;
  26 class WXDLLIMPEXP_BASE wxOutputStream;
  27
  28 typedef wxInputStream& (*__wxInputManip)(wxInputStream&);
  29 typedef wxOutputStream& (*__wxOutputManip)(wxOutputStream&);
  30
  31 WXDLLIMPEXP_BASE wxOutputStream& wxEndL(wxOutputStream& o_stream);
  32
  33 // ----------------------------------------------------------------------------
  34 // constants
  35 // ----------------------------------------------------------------------------
  36
  37 enum wxStreamError
  38 {
  39     wxSTREAM_NO_ERROR = 0,      // stream is in good state
  40     wxSTREAM_EOF,               // EOF reached in Read() or similar
  41     wxSTREAM_WRITE_ERROR,       // generic write error
  42     wxSTREAM_READ_ERROR         // generic read error
  43 };
  44
  45 // compatibility
  46 #if WXWIN_COMPATIBILITY_2_2
  47     #define wxStream_NOERROR    wxSTREAM_NOERROR
  48     #define wxStream_EOF        wxSTREAM_EOF
  49     #define wxStream_WRITE_ERR  wxSTREAM_WRITE_ERROR
  50     #define wxStream_READ_ERR   wxSTREAM_READ_ERROR
  51
  52     #define wxSTREAM_NO_ERR     wxSTREAM_NO_ERROR
  53     #define wxSTREAM_NOERROR    wxSTREAM_NO_ERROR
  54     #define wxSTREAM_WRITE_ERR  wxSTREAM_WRITE_ERROR
  55     #define wxSTREAM_READ_ERR   wxSTREAM_READ_ERROR
  56 #endif // WXWIN_COMPATIBILITY_2_2
  57
  58 // ============================================================================
  59 // base stream classes: wxInputStream and wxOutputStream
  60 // ============================================================================
  61
  62 // ---------------------------------------------------------------------------
  63 // wxStreamBase: common (but non virtual!) base for all stream classes
  64 // ---------------------------------------------------------------------------
  65
  66 class WXDLLIMPEXP_BASE wxStreamBase
  67 {
  68 public:
  69     wxStreamBase();
  70     virtual ~wxStreamBase();
  71
  72     // error testing
  73     wxStreamError GetLastError() const { return m_lasterror; }
  74     bool IsOk() const { return GetLastError() == wxSTREAM_NO_ERROR; }
  75     bool operator!() const { return !IsOk(); }
  76
  77     // reset the stream state
  78     void Reset() { m_lasterror = wxSTREAM_NO_ERROR; }
  79
  80     // this doesn't make sense for all streams, always test its return value
  81     virtual size_t GetSize() const;
  82     virtual wxFileOffset GetLength() const { return wxInvalidOffset; }
  83
  84     // returns true if the streams supports seeking to arbitrary offsets
  85     virtual bool IsSeekable() const { return false; }
  86
  87 #if WXWIN_COMPATIBILITY_2_2
  88     // deprecated, for compatibility only
  89     wxDEPRECATED( wxStreamError LastError() const );
  90     wxDEPRECATED( size_t StreamSize() const );
  91 #endif // WXWIN_COMPATIBILITY_2_2
  92
  93
  94     // Reserved for future use
  95     virtual void ReservedStreamFunc1() {}
  96     virtual void ReservedStreamFunc2() {}
  97     virtual void ReservedStreamFunc3() {}
  98     virtual void ReservedStreamFunc4() {}
  99     virtual void ReservedStreamFunc5() {}
 100     virtual void ReservedStreamFunc6() {}
 101     virtual void ReservedStreamFunc7() {}
 102     virtual void ReservedStreamFunc8() {}
 103     virtual void ReservedStreamFunc9() {}
 104
 105 protected:
 106     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 107     virtual wxFileOffset OnSysTell() const;
 108
 109     size_t m_lastcount;
 110     wxStreamError m_lasterror;
 111
 112     friend class wxStreamBuffer;
 113
 114     DECLARE_NO_COPY_CLASS(wxStreamBase)
 115 };
 116
 117 // ----------------------------------------------------------------------------
 118 // wxInputStream: base class for the input streams
 119 // ----------------------------------------------------------------------------
 120
 121 class WXDLLIMPEXP_BASE wxInputStream : public wxStreamBase
 122 {
 123 public:
 124     // ctor and dtor, nothing exciting
 125     wxInputStream();
 126     virtual ~wxInputStream();
 127
 128
 129     // IO functions
 130     // ------------
 131
 132     // return a character from the stream without removing it, i.e. it will
 133     // still be returned by the next call to GetC()
 134     //
 135     // blocks until something appears in the stream if necessary, if nothing
 136     // ever does (i.e. EOF) LastRead() will return 0 (and the return value is
 137     // undefined), otherwise 1
 138     virtual char Peek();
 139
 140     // return one character from the stream, blocking until it appears if
 141     // necessary
 142     //
 143     // if EOF, return value is undefined and LastRead() will return 0 and not 1
 144     char GetC();
 145
 146     // read at most the given number of bytes from the stream
 147     //
 148     // there are 2 possible situations here: either there is nothing at all in
 149     // the stream right now in which case Read() blocks until something appears
 150     // (use CanRead() to avoid this) or there is already some data available in
 151     // the stream and then Read() doesn't block but returns just the data it
 152     // can read without waiting for more
 153     //
 154     // in any case, if there are not enough bytes in the stream right now,
 155     // LastRead() value will be less than size but greater than 0. If it is 0,
 156     // it means that EOF has been reached.
 157     virtual wxInputStream& Read(void *buffer, size_t size);
 158
 159     // copy the entire contents of this stream into streamOut, stopping only
 160     // when EOF is reached or an error occurs
 161     wxInputStream& Read(wxOutputStream& streamOut);
 162
 163
 164     // status functions
 165     // ----------------
 166
 167     // returns the number of bytes read by the last call to Read(), GetC() or
 168     // Peek()
 169     //
 170     // this should be used to discover whether that call succeeded in reading
 171     // all the requested data or not
 172     virtual size_t LastRead() const { return wxStreamBase::m_lastcount; }
 173
 174     // returns true if some data is available in the stream right now, so that
 175     // calling Read() wouldn't block
 176     virtual bool CanRead() const;
 177
 178     // is the stream at EOF?
 179     //
 180     // note that this cannot be really implemented for all streams and
 181     // CanRead() is more reliable than Eof()
 182     virtual bool Eof() const;
 183
 184
 185     // write back buffer
 186     // -----------------
 187
 188     // put back the specified number of bytes into the stream, they will be
 189     // fetched by the next call to the read functions
 190     //
 191     // returns the number of bytes really stuffed back
 192     size_t Ungetch(const void *buffer, size_t size);
 193
 194     // put back the specified character in the stream
 195     //
 196     // returns true if ok, false on error
 197     bool Ungetch(char c);
 198
 199
 200     // position functions
 201     // ------------------
 202
 203     // move the stream pointer to the given position (if the stream supports
 204     // it)
 205     //
 206     // returns wxInvalidOffset on error
 207     virtual wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 208
 209     // return the current position of the stream pointer or wxInvalidOffset
 210     virtual wxFileOffset TellI() const;
 211
 212
 213     // stream-like operators
 214     // ---------------------
 215
 216     wxInputStream& operator>>(wxOutputStream& out) { return Read(out); }
 217     wxInputStream& operator>>(__wxInputManip func) { return func(*this); }
 218
 219 protected:
 220     // do read up to size bytes of data into the provided buffer
 221     //
 222     // this method should return 0 if EOF has been reached or an error occurred
 223     // (m_lasterror should be set accordingly as well) or the number of bytes
 224     // read
 225     virtual size_t OnSysRead(void *buffer, size_t size) = 0;
 226
 227     // write-back buffer support
 228     // -------------------------
 229
 230     // return the pointer to a buffer big enough to hold sizeNeeded bytes
 231     char *AllocSpaceWBack(size_t sizeNeeded);
 232
 233     // read up to size data from the write back buffer, return the number of
 234     // bytes read
 235     size_t GetWBack(void *buf, size_t size);
 236
 237     // write back buffer or NULL if none
 238     char *m_wback;
 239
 240     // the size of the buffer
 241     size_t m_wbacksize;
 242
 243     // the current position in the buffer
 244     size_t m_wbackcur;
 245
 246     friend class wxStreamBuffer;
 247
 248     DECLARE_NO_COPY_CLASS(wxInputStream)
 249 };
 250
 251 // ----------------------------------------------------------------------------
 252 // wxOutputStream: base for the output streams
 253 // ----------------------------------------------------------------------------
 254
 255 class WXDLLIMPEXP_BASE wxOutputStream : public wxStreamBase
 256 {
 257 public:
 258     wxOutputStream();
 259     virtual ~wxOutputStream();
 260
 261     void PutC(char c);
 262     virtual wxOutputStream& Write(const void *buffer, size_t size);
 263     wxOutputStream& Write(wxInputStream& stream_in);
 264
 265     virtual wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 266     virtual wxFileOffset TellO() const;
 267
 268     virtual size_t LastWrite() const { return wxStreamBase::m_lastcount; }
 269
 270     virtual void Sync();
 271     virtual bool Close() { return true; }
 272
 273     wxOutputStream& operator<<(wxInputStream& out) { return Write(out); }
 274     wxOutputStream& operator<<( __wxOutputManip func) { return func(*this); }
 275
 276 protected:
 277     // to be implemented in the derived classes (it should have been pure
 278     // virtual)
 279     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 280
 281     friend class wxStreamBuffer;
 282
 283     DECLARE_NO_COPY_CLASS(wxOutputStream)
 284 };
 285
 286 // ============================================================================
 287 // helper stream classes
 288 // ============================================================================
 289
 290 // ---------------------------------------------------------------------------
 291 // A stream for measuring streamed output
 292 // ---------------------------------------------------------------------------
 293
 294 class WXDLLIMPEXP_BASE wxCountingOutputStream : public wxOutputStream
 295 {
 296 public:
 297     wxCountingOutputStream();
 298
 299     wxFileOffset GetLength() const;
 300     bool Ok() const { return true; }
 301
 302 protected:
 303     virtual size_t OnSysWrite(const void *buffer, size_t size);
 304     virtual wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode);
 305     virtual wxFileOffset OnSysTell() const;
 306
 307     size_t m_currentPos;
 308
 309     DECLARE_NO_COPY_CLASS(wxCountingOutputStream)
 310 };
 311
 312 // ---------------------------------------------------------------------------
 313 // "Filter" streams
 314 // ---------------------------------------------------------------------------
 315
 316 class WXDLLIMPEXP_BASE wxFilterInputStream : public wxInputStream
 317 {
 318 public:
 319     wxFilterInputStream();
 320     wxFilterInputStream(wxInputStream& stream);
 321     virtual ~wxFilterInputStream();
 322
 323     char Peek() { return m_parent_i_stream->Peek(); }
 324
 325     wxFileOffset GetLength() const { return m_parent_i_stream->GetLength(); }
 326
 327     wxInputStream *GetFilterInputStream() const { return m_parent_i_stream; }
 328
 329 protected:
 330     wxInputStream *m_parent_i_stream;
 331
 332     DECLARE_NO_COPY_CLASS(wxFilterInputStream)
 333 };
 334
 335 class WXDLLIMPEXP_BASE wxFilterOutputStream : public wxOutputStream
 336 {
 337 public:
 338     wxFilterOutputStream();
 339     wxFilterOutputStream(wxOutputStream& stream);
 340     virtual ~wxFilterOutputStream();
 341
 342     wxFileOffset GetLength() const { return m_parent_o_stream->GetLength(); }
 343
 344     wxOutputStream *GetFilterOutputStream() const { return m_parent_o_stream; }
 345
 346 protected:
 347     wxOutputStream *m_parent_o_stream;
 348
 349     DECLARE_NO_COPY_CLASS(wxFilterOutputStream)
 350 };
 351
 352 // ============================================================================
 353 // buffered streams
 354 // ============================================================================
 355
 356 // ---------------------------------------------------------------------------
 357 // Stream buffer: this class can be derived from and passed to
 358 // wxBufferedStreams to implement custom buffering
 359 // ---------------------------------------------------------------------------
 360
 361 class WXDLLIMPEXP_BASE wxStreamBuffer
 362 {
 363 public:
 364     enum BufMode
 365     {
 366         read,
 367         write,
 368         read_write
 369     };
 370
 371     wxStreamBuffer(wxStreamBase& stream, BufMode mode);
 372     wxStreamBuffer(const wxStreamBuffer& buf);
 373     virtual ~wxStreamBuffer();
 374
 375     // Filtered IO
 376     virtual size_t Read(void *buffer, size_t size);
 377     size_t Read(wxStreamBuffer *buf);
 378     virtual size_t Write(const void *buffer, size_t size);
 379     size_t Write(wxStreamBuffer *buf);
 380
 381     virtual char Peek();
 382     virtual char GetChar();
 383     virtual void PutChar(char c);
 384     virtual wxFileOffset Tell() const;
 385     virtual wxFileOffset Seek(wxFileOffset pos, wxSeekMode mode);
 386
 387     // Buffer control
 388     void ResetBuffer();
 389
 390     // NB: the buffer must always be allocated with malloc() if takeOwn is
 391     //     true as it will be deallocated by free()
 392     void SetBufferIO(void *start, void *end, bool takeOwnership = false);
 393     void SetBufferIO(void *start, size_t len, bool takeOwnership = false);
 394     void SetBufferIO(size_t bufsize);
 395     void *GetBufferStart() const { return m_buffer_start; }
 396     void *GetBufferEnd() const { return m_buffer_end; }
 397     void *GetBufferPos() const { return m_buffer_pos; }
 398     size_t GetBufferSize() const { return m_buffer_size; }
 399     size_t GetIntPosition() const { return m_buffer_pos - m_buffer_start; }
 400     void SetIntPosition(size_t pos) { m_buffer_pos = m_buffer_start + pos; }
 401     size_t GetLastAccess() const { return m_buffer_end - m_buffer_start; }
 402     size_t GetBytesLeft() const { return m_buffer_end - m_buffer_pos; }
 403
 404     void Fixed(bool fixed) { m_fixed = fixed; }
 405     void Flushable(bool f) { m_flushable = f; }
 406
 407     bool FlushBuffer();
 408     bool FillBuffer();
 409     size_t GetDataLeft();
 410
 411     // misc accessors
 412     wxStreamBase *GetStream() const { return m_stream; }
 413     bool HasBuffer() const { return m_buffer_size != 0; }
 414
 415     bool IsFixed() const { return m_fixed; }
 416     bool IsFlushable() const { return m_flushable; }
 417
 418     // only for input/output buffers respectively, returns NULL otherwise
 419     wxInputStream *GetInputStream() const;
 420     wxOutputStream *GetOutputStream() const;
 421
 422     // deprecated, for compatibility only
 423     wxStreamBase *Stream() { return m_stream; }
 424
 425     // this constructs a dummy wxStreamBuffer, used by (and exists for)
 426     // wxMemoryStreams only, don't use!
 427     wxStreamBuffer(BufMode mode);
 428
 429 protected:
 430     void GetFromBuffer(void *buffer, size_t size);
 431     void PutToBuffer(const void *buffer, size_t size);
 432
 433     // set the last error to the specified value if we didn't have it before
 434     void SetError(wxStreamError err);
 435
 436     // common part of several ctors
 437     void Init();
 438
 439     // init buffer variables to be empty
 440     void InitBuffer();
 441
 442     // free the buffer (always safe to call)
 443     void FreeBuffer();
 444
 445     // the buffer itself: the pointers to its start and end and the current
 446     // position in the buffer
 447     char *m_buffer_start,
 448          *m_buffer_end,
 449          *m_buffer_pos;
 450
 451     // the buffer size
 452     // FIXME: isn't it the same as m_buffer_end - m_buffer_start? (VZ)
 453     size_t m_buffer_size;
 454
 455     // the stream we're associated with
 456     wxStreamBase *m_stream;
 457
 458     // its mode
 459     BufMode m_mode;
 460
 461     // flags
 462     bool m_destroybuf,      // deallocate buffer?
 463          m_fixed,
 464          m_flushable;
 465
 466 private:
 467 // Cannot use
 468 //  DECLARE_NO_COPY_CLASS(wxStreamBuffer)
 469 // because copy constructor is explicitly declared above;
 470 // but no copy assignment operator is defined, so declare
 471 // it private to prevent the compiler from defining it:
 472     wxStreamBuffer& operator=(const wxStreamBuffer&);
 473 };
 474
 475 // ---------------------------------------------------------------------------
 476 // wxBufferedInputStream
 477 // ---------------------------------------------------------------------------
 478
 479 class WXDLLIMPEXP_BASE wxBufferedInputStream : public wxFilterInputStream
 480 {
 481 public:
 482     // if a non NULL buffer is given to the stream, it will be deleted by it
 483     wxBufferedInputStream(wxInputStream& stream,
 484                           wxStreamBuffer *buffer = NULL);
 485     virtual ~wxBufferedInputStream();
 486
 487     char Peek();
 488     wxInputStream& Read(void *buffer, size_t size);
 489
 490     // Position functions
 491     wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 492     wxFileOffset TellI() const;
 493     bool IsSeekable() const { return m_parent_i_stream->IsSeekable(); }
 494
 495     // the buffer given to the stream will be deleted by it
 496     void SetInputStreamBuffer(wxStreamBuffer *buffer);
 497     wxStreamBuffer *GetInputStreamBuffer() const { return m_i_streambuf; }
 498
 499     // deprecated, for compatibility only
 500     wxStreamBuffer *InputStreamBuffer() const { return m_i_streambuf; }
 501
 502 protected:
 503     virtual size_t OnSysRead(void *buffer, size_t bufsize);
 504     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 505     virtual wxFileOffset OnSysTell() const;
 506
 507     wxStreamBuffer *m_i_streambuf;
 508
 509     DECLARE_NO_COPY_CLASS(wxBufferedInputStream)
 510 };
 511
 512 // ----------------------------------------------------------------------------
 513 // wxBufferedOutputStream
 514 // ----------------------------------------------------------------------------
 515
 516 class WXDLLIMPEXP_BASE wxBufferedOutputStream : public wxFilterOutputStream
 517 {
 518 public:
 519     // if a non NULL buffer is given to the stream, it will be deleted by it
 520     wxBufferedOutputStream(wxOutputStream& stream,
 521                            wxStreamBuffer *buffer = NULL);
 522     virtual ~wxBufferedOutputStream();
 523
 524     wxOutputStream& Write(const void *buffer, size_t size);
 525
 526     // Position functions
 527     wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 528     wxFileOffset TellO() const;
 529     bool IsSeekable() const { return m_parent_o_stream->IsSeekable(); }
 530
 531     void Sync();
 532     bool Close();
 533
 534     wxFileOffset GetLength() const;
 535
 536     // the buffer given to the stream will be deleted by it
 537     void SetOutputStreamBuffer(wxStreamBuffer *buffer);
 538     wxStreamBuffer *GetOutputStreamBuffer() const { return m_o_streambuf; }
 539
 540     // deprecated, for compatibility only
 541     wxStreamBuffer *OutputStreamBuffer() const { return m_o_streambuf; }
 542
 543 protected:
 544     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 545     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 546     virtual wxFileOffset OnSysTell() const;
 547
 548     wxStreamBuffer *m_o_streambuf;
 549
 550     DECLARE_NO_COPY_CLASS(wxBufferedOutputStream)
 551 };
 552
 553 #endif // wxUSE_STREAMS
 554
 555 #endif // _WX_WXSTREAM_H__
 556