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 const int wxEOF = -1;
  46
  47 // ============================================================================
  48 // base stream classes: wxInputStream and wxOutputStream
  49 // ============================================================================
  50
  51 // ---------------------------------------------------------------------------
  52 // wxStreamBase: common (but non virtual!) base for all stream classes
  53 // ---------------------------------------------------------------------------
  54
  55 class WXDLLIMPEXP_BASE wxStreamBase : public wxObject
  56 {
  57 public:
  58     wxStreamBase();
  59     virtual ~wxStreamBase();
  60
  61     // error testing
  62     wxStreamError GetLastError() const { return m_lasterror; }
  63     virtual bool IsOk() const { return GetLastError() == wxSTREAM_NO_ERROR; }
  64     bool operator!() const { return !IsOk(); }
  65
  66     // reset the stream state
  67     void Reset() { m_lasterror = wxSTREAM_NO_ERROR; }
  68
  69     // this doesn't make sense for all streams, always test its return value
  70     virtual size_t GetSize() const;
  71     virtual wxFileOffset GetLength() const { return wxInvalidOffset; }
  72
  73     // returns true if the streams supports seeking to arbitrary offsets
  74     virtual bool IsSeekable() const { return false; }
  75
  76 protected:
  77     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
  78     virtual wxFileOffset OnSysTell() const;
  79
  80     size_t m_lastcount;
  81     wxStreamError m_lasterror;
  82
  83     friend class wxStreamBuffer;
  84
  85     DECLARE_ABSTRACT_CLASS(wxStreamBase)
  86     DECLARE_NO_COPY_CLASS(wxStreamBase)
  87 };
  88
  89 // ----------------------------------------------------------------------------
  90 // wxInputStream: base class for the input streams
  91 // ----------------------------------------------------------------------------
  92
  93 class WXDLLIMPEXP_BASE wxInputStream : public wxStreamBase
  94 {
  95 public:
  96     // ctor and dtor, nothing exciting
  97     wxInputStream();
  98     virtual ~wxInputStream();
  99
 100
 101     // IO functions
 102     // ------------
 103
 104     // return a character from the stream without removing it, i.e. it will
 105     // still be returned by the next call to GetC()
 106     //
 107     // blocks until something appears in the stream if necessary, if nothing
 108     // ever does (i.e. EOF) LastRead() will return 0 (and the return value is
 109     // undefined), otherwise 1
 110     virtual char Peek();
 111
 112     // return one byte from the stream, blocking until it appears if
 113     // necessary
 114     //
 115     // on success returns a value between 0 - 255, or wxEOF on EOF or error.
 116     int GetC();
 117
 118     // read at most the given number of bytes from the stream
 119     //
 120     // there are 2 possible situations here: either there is nothing at all in
 121     // the stream right now in which case Read() blocks until something appears
 122     // (use CanRead() to avoid this) or there is already some data available in
 123     // the stream and then Read() doesn't block but returns just the data it
 124     // can read without waiting for more
 125     //
 126     // in any case, if there are not enough bytes in the stream right now,
 127     // LastRead() value will be less than size but greater than 0. If it is 0,
 128     // it means that EOF has been reached.
 129     virtual wxInputStream& Read(void *buffer, size_t size);
 130
 131     // copy the entire contents of this stream into streamOut, stopping only
 132     // when EOF is reached or an error occurs
 133     wxInputStream& Read(wxOutputStream& streamOut);
 134
 135
 136     // status functions
 137     // ----------------
 138
 139     // returns the number of bytes read by the last call to Read(), GetC() or
 140     // Peek()
 141     //
 142     // this should be used to discover whether that call succeeded in reading
 143     // all the requested data or not
 144     virtual size_t LastRead() const { return wxStreamBase::m_lastcount; }
 145
 146     // returns true if some data is available in the stream right now, so that
 147     // calling Read() wouldn't block
 148     virtual bool CanRead() const;
 149
 150     // is the stream at EOF?
 151     //
 152     // note that this cannot be really implemented for all streams and
 153     // CanRead() is more reliable than Eof()
 154     virtual bool Eof() const;
 155
 156
 157     // write back buffer
 158     // -----------------
 159
 160     // put back the specified number of bytes into the stream, they will be
 161     // fetched by the next call to the read functions
 162     //
 163     // returns the number of bytes really stuffed back
 164     size_t Ungetch(const void *buffer, size_t size);
 165
 166     // put back the specified character in the stream
 167     //
 168     // returns true if ok, false on error
 169     bool Ungetch(char c);
 170
 171
 172     // position functions
 173     // ------------------
 174
 175     // move the stream pointer to the given position (if the stream supports
 176     // it)
 177     //
 178     // returns wxInvalidOffset on error
 179     virtual wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 180
 181     // return the current position of the stream pointer or wxInvalidOffset
 182     virtual wxFileOffset TellI() const;
 183
 184
 185     // stream-like operators
 186     // ---------------------
 187
 188     wxInputStream& operator>>(wxOutputStream& out) { return Read(out); }
 189     wxInputStream& operator>>(__wxInputManip func) { return func(*this); }
 190
 191 protected:
 192     // do read up to size bytes of data into the provided buffer
 193     //
 194     // this method should return 0 if EOF has been reached or an error occurred
 195     // (m_lasterror should be set accordingly as well) or the number of bytes
 196     // read
 197     virtual size_t OnSysRead(void *buffer, size_t size) = 0;
 198
 199     // write-back buffer support
 200     // -------------------------
 201
 202     // return the pointer to a buffer big enough to hold sizeNeeded bytes
 203     char *AllocSpaceWBack(size_t sizeNeeded);
 204
 205     // read up to size data from the write back buffer, return the number of
 206     // bytes read
 207     size_t GetWBack(void *buf, size_t size);
 208
 209     // write back buffer or NULL if none
 210     char *m_wback;
 211
 212     // the size of the buffer
 213     size_t m_wbacksize;
 214
 215     // the current position in the buffer
 216     size_t m_wbackcur;
 217
 218     friend class wxStreamBuffer;
 219
 220     DECLARE_ABSTRACT_CLASS(wxInputStream)
 221     DECLARE_NO_COPY_CLASS(wxInputStream)
 222 };
 223
 224 // ----------------------------------------------------------------------------
 225 // wxOutputStream: base for the output streams
 226 // ----------------------------------------------------------------------------
 227
 228 class WXDLLIMPEXP_BASE wxOutputStream : public wxStreamBase
 229 {
 230 public:
 231     wxOutputStream();
 232     virtual ~wxOutputStream();
 233
 234     void PutC(char c);
 235     virtual wxOutputStream& Write(const void *buffer, size_t size);
 236     wxOutputStream& Write(wxInputStream& stream_in);
 237
 238     virtual wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 239     virtual wxFileOffset TellO() const;
 240
 241     virtual size_t LastWrite() const { return wxStreamBase::m_lastcount; }
 242
 243     virtual void Sync();
 244     virtual bool Close() { return true; }
 245
 246     wxOutputStream& operator<<(wxInputStream& out) { return Write(out); }
 247     wxOutputStream& operator<<( __wxOutputManip func) { return func(*this); }
 248
 249 protected:
 250     // to be implemented in the derived classes (it should have been pure
 251     // virtual)
 252     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 253
 254     friend class wxStreamBuffer;
 255
 256     DECLARE_ABSTRACT_CLASS(wxOutputStream)
 257     DECLARE_NO_COPY_CLASS(wxOutputStream)
 258 };
 259
 260 // ============================================================================
 261 // helper stream classes
 262 // ============================================================================
 263
 264 // ---------------------------------------------------------------------------
 265 // A stream for measuring streamed output
 266 // ---------------------------------------------------------------------------
 267
 268 class WXDLLIMPEXP_BASE wxCountingOutputStream : public wxOutputStream
 269 {
 270 public:
 271     wxCountingOutputStream();
 272
 273     wxFileOffset GetLength() const;
 274     bool Ok() const { return IsOk(); }
 275     bool IsOk() const { return true; }
 276
 277 protected:
 278     virtual size_t OnSysWrite(const void *buffer, size_t size);
 279     virtual wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode);
 280     virtual wxFileOffset OnSysTell() const;
 281
 282     size_t m_currentPos;
 283
 284     DECLARE_DYNAMIC_CLASS(wxCountingOutputStream)
 285     DECLARE_NO_COPY_CLASS(wxCountingOutputStream)
 286 };
 287
 288 // ---------------------------------------------------------------------------
 289 // "Filter" streams
 290 // ---------------------------------------------------------------------------
 291
 292 class WXDLLIMPEXP_BASE wxFilterInputStream : public wxInputStream
 293 {
 294 public:
 295     wxFilterInputStream();
 296     wxFilterInputStream(wxInputStream& stream);
 297     wxFilterInputStream(wxInputStream *stream);
 298     virtual ~wxFilterInputStream();
 299
 300     char Peek() { return m_parent_i_stream->Peek(); }
 301
 302     wxFileOffset GetLength() const { return m_parent_i_stream->GetLength(); }
 303
 304     wxInputStream *GetFilterInputStream() const { return m_parent_i_stream; }
 305
 306 protected:
 307     wxInputStream *m_parent_i_stream;
 308     bool m_owns;
 309
 310     DECLARE_ABSTRACT_CLASS(wxFilterInputStream)
 311     DECLARE_NO_COPY_CLASS(wxFilterInputStream)
 312 };
 313
 314 class WXDLLIMPEXP_BASE wxFilterOutputStream : public wxOutputStream
 315 {
 316 public:
 317     wxFilterOutputStream();
 318     wxFilterOutputStream(wxOutputStream& stream);
 319     wxFilterOutputStream(wxOutputStream *stream);
 320     virtual ~wxFilterOutputStream();
 321
 322     wxFileOffset GetLength() const { return m_parent_o_stream->GetLength(); }
 323
 324     wxOutputStream *GetFilterOutputStream() const { return m_parent_o_stream; }
 325
 326     bool Close();
 327
 328 protected:
 329     wxOutputStream *m_parent_o_stream;
 330     bool m_owns;
 331
 332     DECLARE_ABSTRACT_CLASS(wxFilterOutputStream)
 333     DECLARE_NO_COPY_CLASS(wxFilterOutputStream)
 334 };
 335
 336 enum wxStreamProtocolType
 337 {
 338     wxSTREAM_PROTOCOL,  // wxFileSystem protocol (should be only one)
 339     wxSTREAM_MIMETYPE,  // MIME types the stream handles
 340     wxSTREAM_ENCODING,  // The HTTP Content-Encodings the stream handles
 341     wxSTREAM_FILEEXT    // File extensions the stream handles
 342 };
 343
 344 void WXDLLIMPEXP_BASE wxUseFilterClasses();
 345
 346 class WXDLLIMPEXP_BASE wxFilterClassFactoryBase : public wxObject
 347 {
 348 public:
 349     virtual ~wxFilterClassFactoryBase() { }
 350
 351     wxString GetProtocol() const { return wxString(*GetProtocols()); }
 352     wxString PopExtension(const wxString& location) const;
 353
 354     virtual const wxChar * const *GetProtocols(wxStreamProtocolType type
 355                                                = wxSTREAM_PROTOCOL) const = 0;
 356
 357     bool CanHandle(const wxString& protocol,
 358                    wxStreamProtocolType type
 359                    = wxSTREAM_PROTOCOL) const;
 360
 361 protected:
 362     wxString::size_type FindExtension(const wxString& location) const;
 363
 364     DECLARE_ABSTRACT_CLASS(wxFilterClassFactoryBase)
 365 };
 366
 367 class WXDLLIMPEXP_BASE wxFilterClassFactory : public wxFilterClassFactoryBase
 368 {
 369 public:
 370     virtual ~wxFilterClassFactory() { }
 371
 372     virtual wxFilterInputStream  *NewStream(wxInputStream& stream)  const = 0;
 373     virtual wxFilterOutputStream *NewStream(wxOutputStream& stream) const = 0;
 374     virtual wxFilterInputStream  *NewStream(wxInputStream *stream)  const = 0;
 375     virtual wxFilterOutputStream *NewStream(wxOutputStream *stream) const = 0;
 376
 377     static const wxFilterClassFactory *Find(const wxString& protocol,
 378                                             wxStreamProtocolType type
 379                                             = wxSTREAM_PROTOCOL);
 380
 381     static const wxFilterClassFactory *GetFirst();
 382     const wxFilterClassFactory *GetNext() const { return m_next; }
 383
 384     void PushFront() { Remove(); m_next = sm_first; sm_first = this; }
 385     void Remove();
 386
 387 protected:
 388     wxFilterClassFactory() : m_next(this) { }
 389
 390     wxFilterClassFactory& operator=(const wxFilterClassFactory&)
 391         { return *this; }
 392
 393 private:
 394     static wxFilterClassFactory *sm_first;
 395     wxFilterClassFactory *m_next;
 396
 397     DECLARE_ABSTRACT_CLASS(wxFilterClassFactory)
 398 };
 399
 400 // ============================================================================
 401 // buffered streams
 402 // ============================================================================
 403
 404 // ---------------------------------------------------------------------------
 405 // Stream buffer: this class can be derived from and passed to
 406 // wxBufferedStreams to implement custom buffering
 407 // ---------------------------------------------------------------------------
 408
 409 class WXDLLIMPEXP_BASE wxStreamBuffer
 410 {
 411 public:
 412     enum BufMode
 413     {
 414         read,
 415         write,
 416         read_write
 417     };
 418
 419     wxStreamBuffer(wxStreamBase& stream, BufMode mode);
 420     wxStreamBuffer(const wxStreamBuffer& buf);
 421     virtual ~wxStreamBuffer();
 422
 423     // Filtered IO
 424     virtual size_t Read(void *buffer, size_t size);
 425     size_t Read(wxStreamBuffer *buf);
 426     virtual size_t Write(const void *buffer, size_t size);
 427     size_t Write(wxStreamBuffer *buf);
 428
 429     virtual char Peek();
 430     virtual char GetChar();
 431     virtual void PutChar(char c);
 432     virtual wxFileOffset Tell() const;
 433     virtual wxFileOffset Seek(wxFileOffset pos, wxSeekMode mode);
 434
 435     // Buffer control
 436     void ResetBuffer();
 437     void Truncate();
 438
 439     // NB: the buffer must always be allocated with malloc() if takeOwn is
 440     //     true as it will be deallocated by free()
 441     void SetBufferIO(void *start, void *end, bool takeOwnership = false);
 442     void SetBufferIO(void *start, size_t len, bool takeOwnership = false);
 443     void SetBufferIO(size_t bufsize);
 444     void *GetBufferStart() const { return m_buffer_start; }
 445     void *GetBufferEnd() const { return m_buffer_end; }
 446     void *GetBufferPos() const { return m_buffer_pos; }
 447     size_t GetBufferSize() const { return m_buffer_size; }
 448     size_t GetIntPosition() const { return m_buffer_pos - m_buffer_start; }
 449     void SetIntPosition(size_t pos) { m_buffer_pos = m_buffer_start + pos; }
 450     size_t GetLastAccess() const { return m_buffer_end - m_buffer_start; }
 451     size_t GetBytesLeft() const { return m_buffer_end - m_buffer_pos; }
 452
 453     void Fixed(bool fixed) { m_fixed = fixed; }
 454     void Flushable(bool f) { m_flushable = f; }
 455
 456     bool FlushBuffer();
 457     bool FillBuffer();
 458     size_t GetDataLeft();
 459
 460     // misc accessors
 461     wxStreamBase *GetStream() const { return m_stream; }
 462     bool HasBuffer() const { return m_buffer_size != 0; }
 463
 464     bool IsFixed() const { return m_fixed; }
 465     bool IsFlushable() const { return m_flushable; }
 466
 467     // only for input/output buffers respectively, returns NULL otherwise
 468     wxInputStream *GetInputStream() const;
 469     wxOutputStream *GetOutputStream() const;
 470
 471 #if WXWIN_COMPATIBILITY_2_6
 472     // deprecated, for compatibility only
 473     wxDEPRECATED( wxStreamBase *Stream() );
 474 #endif // WXWIN_COMPATIBILITY_2_6
 475
 476     // this constructs a dummy wxStreamBuffer, used by (and exists for)
 477     // wxMemoryStreams only, don't use!
 478     wxStreamBuffer(BufMode mode);
 479
 480 protected:
 481     void GetFromBuffer(void *buffer, size_t size);
 482     void PutToBuffer(const void *buffer, size_t size);
 483
 484     // set the last error to the specified value if we didn't have it before
 485     void SetError(wxStreamError err);
 486
 487     // common part of several ctors
 488     void Init();
 489
 490     // init buffer variables to be empty
 491     void InitBuffer();
 492
 493     // free the buffer (always safe to call)
 494     void FreeBuffer();
 495
 496     // the buffer itself: the pointers to its start and end and the current
 497     // position in the buffer
 498     char *m_buffer_start,
 499          *m_buffer_end,
 500          *m_buffer_pos;
 501
 502     // the buffer size
 503     // FIXME: isn't it the same as m_buffer_end - m_buffer_start? (VZ)
 504     size_t m_buffer_size;
 505
 506     // the stream we're associated with
 507     wxStreamBase *m_stream;
 508
 509     // its mode
 510     BufMode m_mode;
 511
 512     // flags
 513     bool m_destroybuf,      // deallocate buffer?
 514          m_fixed,
 515          m_flushable;
 516
 517 private:
 518 // Cannot use
 519 //  DECLARE_NO_COPY_CLASS(wxStreamBuffer)
 520 // because copy constructor is explicitly declared above;
 521 // but no copy assignment operator is defined, so declare
 522 // it private to prevent the compiler from defining it:
 523     wxStreamBuffer& operator=(const wxStreamBuffer&);
 524 };
 525
 526 // ---------------------------------------------------------------------------
 527 // wxBufferedInputStream
 528 // ---------------------------------------------------------------------------
 529
 530 class WXDLLIMPEXP_BASE wxBufferedInputStream : public wxFilterInputStream
 531 {
 532 public:
 533     // if a non NULL buffer is given to the stream, it will be deleted by it
 534     wxBufferedInputStream(wxInputStream& stream,
 535                           wxStreamBuffer *buffer = NULL);
 536     virtual ~wxBufferedInputStream();
 537
 538     char Peek();
 539     wxInputStream& Read(void *buffer, size_t size);
 540
 541     // Position functions
 542     wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 543     wxFileOffset TellI() const;
 544     bool IsSeekable() const { return m_parent_i_stream->IsSeekable(); }
 545
 546     // the buffer given to the stream will be deleted by it
 547     void SetInputStreamBuffer(wxStreamBuffer *buffer);
 548     wxStreamBuffer *GetInputStreamBuffer() const { return m_i_streambuf; }
 549
 550 #if WXWIN_COMPATIBILITY_2_6
 551     // deprecated, for compatibility only
 552     wxDEPRECATED( wxStreamBuffer *InputStreamBuffer() const );
 553 #endif // WXWIN_COMPATIBILITY_2_6
 554
 555 protected:
 556     virtual size_t OnSysRead(void *buffer, size_t bufsize);
 557     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 558     virtual wxFileOffset OnSysTell() const;
 559
 560     wxStreamBuffer *m_i_streambuf;
 561
 562     DECLARE_NO_COPY_CLASS(wxBufferedInputStream)
 563 };
 564
 565 // ----------------------------------------------------------------------------
 566 // wxBufferedOutputStream
 567 // ----------------------------------------------------------------------------
 568
 569 class WXDLLIMPEXP_BASE wxBufferedOutputStream : public wxFilterOutputStream
 570 {
 571 public:
 572     // if a non NULL buffer is given to the stream, it will be deleted by it
 573     wxBufferedOutputStream(wxOutputStream& stream,
 574                            wxStreamBuffer *buffer = NULL);
 575     virtual ~wxBufferedOutputStream();
 576
 577     wxOutputStream& Write(const void *buffer, size_t size);
 578
 579     // Position functions
 580     wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 581     wxFileOffset TellO() const;
 582     bool IsSeekable() const { return m_parent_o_stream->IsSeekable(); }
 583
 584     void Sync();
 585     bool Close();
 586
 587     wxFileOffset GetLength() const;
 588
 589     // the buffer given to the stream will be deleted by it
 590     void SetOutputStreamBuffer(wxStreamBuffer *buffer);
 591     wxStreamBuffer *GetOutputStreamBuffer() const { return m_o_streambuf; }
 592
 593 #if WXWIN_COMPATIBILITY_2_6
 594     // deprecated, for compatibility only
 595     wxDEPRECATED( wxStreamBuffer *OutputStreamBuffer() const );
 596 #endif // WXWIN_COMPATIBILITY_2_6
 597
 598 protected:
 599     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 600     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 601     virtual wxFileOffset OnSysTell() const;
 602
 603     wxStreamBuffer *m_o_streambuf;
 604
 605     DECLARE_NO_COPY_CLASS(wxBufferedOutputStream)
 606 };
 607
 608 #if WXWIN_COMPATIBILITY_2_6
 609     inline wxStreamBase *wxStreamBuffer::Stream() { return m_stream; }
 610     inline wxStreamBuffer *wxBufferedInputStream::InputStreamBuffer() const { return m_i_streambuf; }
 611     inline wxStreamBuffer *wxBufferedOutputStream::OutputStreamBuffer() const { return m_o_streambuf; }
 612 #endif // WXWIN_COMPATIBILITY_2_6
 613
 614 #endif // wxUSE_STREAMS
 615
 616 #endif // _WX_WXSTREAM_H__