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