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 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  16 #pragma interface "stream.h"
  17 #endif
  18
  19 #include "wx/defs.h"
  20
  21 #if wxUSE_STREAMS
  22
  23 #include <stdio.h>
  24 #include "wx/object.h"
  25 #include "wx/string.h"
  26 #include "wx/filefn.h"  // for wxFileOffset, wxInvalidOffset and wxSeekMode
  27
  28 class WXDLLIMPEXP_BASE wxStreamBase;
  29 class WXDLLIMPEXP_BASE wxInputStream;
  30 class WXDLLIMPEXP_BASE wxOutputStream;
  31
  32 typedef wxInputStream& (*__wxInputManip)(wxInputStream&);
  33 typedef wxOutputStream& (*__wxOutputManip)(wxOutputStream&);
  34
  35 WXDLLIMPEXP_BASE wxOutputStream& wxEndL(wxOutputStream& o_stream);
  36
  37 // ----------------------------------------------------------------------------
  38 // constants
  39 // ----------------------------------------------------------------------------
  40
  41 enum wxStreamError
  42 {
  43     wxSTREAM_NO_ERROR = 0,      // stream is in good state
  44     wxSTREAM_EOF,               // EOF reached in Read() or similar
  45     wxSTREAM_WRITE_ERROR,       // generic write error
  46     wxSTREAM_READ_ERROR         // generic read error
  47 };
  48
  49 // compatibility
  50 #if WXWIN_COMPATIBILITY_2_2
  51     #define wxStream_NOERROR    wxSTREAM_NOERROR
  52     #define wxStream_EOF        wxSTREAM_EOF
  53     #define wxStream_WRITE_ERR  wxSTREAM_WRITE_ERROR
  54     #define wxStream_READ_ERR   wxSTREAM_READ_ERROR
  55
  56     #define wxSTREAM_NO_ERR     wxSTREAM_NO_ERROR
  57     #define wxSTREAM_NOERROR    wxSTREAM_NO_ERROR
  58     #define wxSTREAM_WRITE_ERR  wxSTREAM_WRITE_ERROR
  59     #define wxSTREAM_READ_ERR   wxSTREAM_READ_ERROR
  60 #endif // WXWIN_COMPATIBILITY_2_2
  61
  62 // ============================================================================
  63 // base stream classes: wxInputStream and wxOutputStream
  64 // ============================================================================
  65
  66 // ---------------------------------------------------------------------------
  67 // wxStreamBase: common (but non virtual!) base for all stream classes
  68 // ---------------------------------------------------------------------------
  69
  70 class WXDLLIMPEXP_BASE wxStreamBase
  71 {
  72 public:
  73     wxStreamBase();
  74     virtual ~wxStreamBase();
  75
  76     // error testing
  77     wxStreamError GetLastError() const { return m_lasterror; }
  78     bool IsOk() const { return GetLastError() == wxSTREAM_NO_ERROR; }
  79     bool operator!() const { return !IsOk(); }
  80
  81     // reset the stream state
  82     void Reset() { m_lasterror = wxSTREAM_NO_ERROR; }
  83
  84     // this doesn't make sense for all streams, always test its return value
  85     virtual size_t GetSize() const;
  86     virtual wxFileOffset GetLength() const { return wxInvalidOffset; }
  87
  88     // returns true if the streams supports seeking to arbitrary offsets
  89     virtual bool IsSeekable() const { return false; }
  90
  91 #if WXWIN_COMPATIBILITY_2_2
  92     // deprecated, for compatibility only
  93     wxDEPRECATED( wxStreamError LastError() const );
  94     wxDEPRECATED( size_t StreamSize() const );
  95 #endif // WXWIN_COMPATIBILITY_2_2
  96
  97
  98     // Reserved for future use
  99     virtual void ReservedStreamFunc1() {}
 100     virtual void ReservedStreamFunc2() {}
 101     virtual void ReservedStreamFunc3() {}
 102     virtual void ReservedStreamFunc4() {}
 103     virtual void ReservedStreamFunc5() {}
 104     virtual void ReservedStreamFunc6() {}
 105     virtual void ReservedStreamFunc7() {}
 106     virtual void ReservedStreamFunc8() {}
 107     virtual void ReservedStreamFunc9() {}
 108
 109 protected:
 110     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 111     virtual wxFileOffset OnSysTell() const;
 112
 113     size_t m_lastcount;
 114     wxStreamError m_lasterror;
 115
 116     friend class wxStreamBuffer;
 117
 118     DECLARE_NO_COPY_CLASS(wxStreamBase)
 119 };
 120
 121 // ----------------------------------------------------------------------------
 122 // wxInputStream: base class for the input streams
 123 // ----------------------------------------------------------------------------
 124
 125 class WXDLLIMPEXP_BASE wxInputStream : public wxStreamBase
 126 {
 127 public:
 128     // ctor and dtor, nothing exciting
 129     wxInputStream();
 130     virtual ~wxInputStream();
 131
 132
 133     // IO functions
 134     // ------------
 135
 136     // return a character from the stream without removing it, i.e. it will
 137     // still be returned by the next call to GetC()
 138     //
 139     // blocks until something appears in the stream if necessary, if nothing
 140     // ever does (i.e. EOF) LastRead() will return 0 (and the return value is
 141     // undefined), otherwise 1
 142     virtual char Peek();
 143
 144     // return one character from the stream, blocking until it appears if
 145     // necessary
 146     //
 147     // if EOF, return value is undefined and LastRead() will return 0 and not 1
 148     char GetC();
 149
 150     // read at most the given number of bytes from the stream
 151     //
 152     // there are 2 possible situations here: either there is nothing at all in
 153     // the stream right now in which case Read() blocks until something appears
 154     // (use CanRead() to avoid this) or there is already some data available in
 155     // the stream and then Read() doesn't block but returns just the data it
 156     // can read without waiting for more
 157     //
 158     // in any case, if there are not enough bytes in the stream right now,
 159     // LastRead() value will be less than size but greater than 0. If it is 0,
 160     // it means that EOF has been reached.
 161     virtual wxInputStream& Read(void *buffer, size_t size);
 162
 163     // copy the entire contents of this stream into streamOut, stopping only
 164     // when EOF is reached or an error occurs
 165     wxInputStream& Read(wxOutputStream& streamOut);
 166
 167
 168     // status functions
 169     // ----------------
 170
 171     // returns the number of bytes read by the last call to Read(), GetC() or
 172     // Peek()
 173     //
 174     // this should be used to discover whether that call succeeded in reading
 175     // all the requested data or not
 176     virtual size_t LastRead() const { return wxStreamBase::m_lastcount; }
 177
 178     // returns true if some data is available in the stream right now, so that
 179     // calling Read() wouldn't block
 180     virtual bool CanRead() const;
 181
 182     // is the stream at EOF?
 183     //
 184     // note that this cannot be really implemented for all streams and
 185     // CanRead() is more reliable than Eof()
 186     virtual bool Eof() const;
 187
 188
 189     // write back buffer
 190     // -----------------
 191
 192     // put back the specified number of bytes into the stream, they will be
 193     // fetched by the next call to the read functions
 194     //
 195     // returns the number of bytes really stuffed back
 196     size_t Ungetch(const void *buffer, size_t size);
 197
 198     // put back the specified character in the stream
 199     //
 200     // returns true if ok, false on error
 201     bool Ungetch(char c);
 202
 203
 204     // position functions
 205     // ------------------
 206
 207     // move the stream pointer to the given position (if the stream supports
 208     // it)
 209     //
 210     // returns wxInvalidOffset on error
 211     virtual wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 212
 213     // return the current position of the stream pointer or wxInvalidOffset
 214     virtual wxFileOffset TellI() const;
 215
 216
 217     // stream-like operators
 218     // ---------------------
 219
 220     wxInputStream& operator>>(wxOutputStream& out) { return Read(out); }
 221     wxInputStream& operator>>(__wxInputManip func) { return func(*this); }
 222
 223 protected:
 224     // do read up to size bytes of data into the provided buffer
 225     //
 226     // this method should return 0 if EOF has been reached or an error occurred
 227     // (m_lasterror should be set accordingly as well) or the number of bytes
 228     // read
 229     virtual size_t OnSysRead(void *buffer, size_t size) = 0;
 230
 231     // write-back buffer support
 232     // -------------------------
 233
 234     // return the pointer to a buffer big enough to hold sizeNeeded bytes
 235     char *AllocSpaceWBack(size_t sizeNeeded);
 236
 237     // read up to size data from the write back buffer, return the number of
 238     // bytes read
 239     size_t GetWBack(void *buf, size_t size);
 240
 241     // write back buffer or NULL if none
 242     char *m_wback;
 243
 244     // the size of the buffer
 245     size_t m_wbacksize;
 246
 247     // the current position in the buffer
 248     size_t m_wbackcur;
 249
 250     friend class wxStreamBuffer;
 251
 252     DECLARE_NO_COPY_CLASS(wxInputStream)
 253 };
 254
 255 // ----------------------------------------------------------------------------
 256 // wxOutputStream: base for the output streams
 257 // ----------------------------------------------------------------------------
 258
 259 class WXDLLIMPEXP_BASE wxOutputStream : public wxStreamBase
 260 {
 261 public:
 262     wxOutputStream();
 263     virtual ~wxOutputStream();
 264
 265     void PutC(char c);
 266     virtual wxOutputStream& Write(const void *buffer, size_t size);
 267     wxOutputStream& Write(wxInputStream& stream_in);
 268
 269     virtual wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 270     virtual wxFileOffset TellO() const;
 271
 272     virtual size_t LastWrite() const { return wxStreamBase::m_lastcount; }
 273
 274     virtual void Sync();
 275     virtual bool Close() { return true; }
 276
 277     wxOutputStream& operator<<(wxInputStream& out) { return Write(out); }
 278     wxOutputStream& operator<<( __wxOutputManip func) { return func(*this); }
 279
 280 protected:
 281     // to be implemented in the derived classes (it should have been pure
 282     // virtual)
 283     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 284
 285     friend class wxStreamBuffer;
 286
 287     DECLARE_NO_COPY_CLASS(wxOutputStream)
 288 };
 289
 290 // ============================================================================
 291 // helper stream classes
 292 // ============================================================================
 293
 294 // ---------------------------------------------------------------------------
 295 // A stream for measuring streamed output
 296 // ---------------------------------------------------------------------------
 297
 298 class WXDLLIMPEXP_BASE wxCountingOutputStream : public wxOutputStream
 299 {
 300 public:
 301     wxCountingOutputStream();
 302
 303     wxFileOffset GetLength() const;
 304     bool Ok() const { return true; }
 305
 306 protected:
 307     virtual size_t OnSysWrite(const void *buffer, size_t size);
 308     virtual wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode);
 309     virtual wxFileOffset OnSysTell() const;
 310
 311     size_t m_currentPos;
 312
 313     DECLARE_NO_COPY_CLASS(wxCountingOutputStream)
 314 };
 315
 316 // ---------------------------------------------------------------------------
 317 // "Filter" streams
 318 // ---------------------------------------------------------------------------
 319
 320 class WXDLLIMPEXP_BASE wxFilterInputStream : public wxInputStream
 321 {
 322 public:
 323     wxFilterInputStream();
 324     wxFilterInputStream(wxInputStream& stream);
 325     virtual ~wxFilterInputStream();
 326
 327     char Peek() { return m_parent_i_stream->Peek(); }
 328
 329     wxFileOffset GetLength() const { return m_parent_i_stream->GetLength(); }
 330
 331     wxInputStream *GetFilterInputStream() const { return m_parent_i_stream; }
 332
 333 protected:
 334     wxInputStream *m_parent_i_stream;
 335
 336     DECLARE_NO_COPY_CLASS(wxFilterInputStream)
 337 };
 338
 339 class WXDLLIMPEXP_BASE wxFilterOutputStream : public wxOutputStream
 340 {
 341 public:
 342     wxFilterOutputStream();
 343     wxFilterOutputStream(wxOutputStream& stream);
 344     virtual ~wxFilterOutputStream();
 345
 346     wxFileOffset GetLength() const { return m_parent_o_stream->GetLength(); }
 347
 348     wxOutputStream *GetFilterOutputStream() const { return m_parent_o_stream; }
 349
 350 protected:
 351     wxOutputStream *m_parent_o_stream;
 352
 353     DECLARE_NO_COPY_CLASS(wxFilterOutputStream)
 354 };
 355
 356 // ============================================================================
 357 // buffered streams
 358 // ============================================================================
 359
 360 // ---------------------------------------------------------------------------
 361 // Stream buffer: this class can be derived from and passed to
 362 // wxBufferedStreams to implement custom buffering
 363 // ---------------------------------------------------------------------------
 364
 365 class WXDLLIMPEXP_BASE wxStreamBuffer
 366 {
 367 public:
 368     enum BufMode
 369     {
 370         read,
 371         write,
 372         read_write
 373     };
 374
 375     wxStreamBuffer(wxStreamBase& stream, BufMode mode);
 376     wxStreamBuffer(const wxStreamBuffer& buf);
 377     virtual ~wxStreamBuffer();
 378
 379     // Filtered IO
 380     virtual size_t Read(void *buffer, size_t size);
 381     size_t Read(wxStreamBuffer *buf);
 382     virtual size_t Write(const void *buffer, size_t size);
 383     size_t Write(wxStreamBuffer *buf);
 384
 385     virtual char Peek();
 386     virtual char GetChar();
 387     virtual void PutChar(char c);
 388     virtual wxFileOffset Tell() const;
 389     virtual wxFileOffset Seek(wxFileOffset pos, wxSeekMode mode);
 390
 391     // Buffer control
 392     void ResetBuffer();
 393
 394     // NB: the buffer must always be allocated with malloc() if takeOwn is
 395     //     true as it will be deallocated by free()
 396     void SetBufferIO(void *start, void *end, bool takeOwnership = false);
 397     void SetBufferIO(void *start, size_t len, bool takeOwnership = false);
 398     void SetBufferIO(size_t bufsize);
 399     void *GetBufferStart() const { return m_buffer_start; }
 400     void *GetBufferEnd() const { return m_buffer_end; }
 401     void *GetBufferPos() const { return m_buffer_pos; }
 402     size_t GetBufferSize() const { return m_buffer_size; }
 403     size_t GetIntPosition() const { return m_buffer_pos - m_buffer_start; }
 404     void SetIntPosition(size_t pos) { m_buffer_pos = m_buffer_start + pos; }
 405     size_t GetLastAccess() const { return m_buffer_end - m_buffer_start; }
 406     size_t GetBytesLeft() const { return m_buffer_end - m_buffer_pos; }
 407
 408     void Fixed(bool fixed) { m_fixed = fixed; }
 409     void Flushable(bool f) { m_flushable = f; }
 410
 411     bool FlushBuffer();
 412     bool FillBuffer();
 413     size_t GetDataLeft();
 414
 415     // misc accessors
 416     wxStreamBase *GetStream() const { return m_stream; }
 417     bool HasBuffer() const { return m_buffer_size != 0; }
 418
 419     bool IsFixed() const { return m_fixed; }
 420     bool IsFlushable() const { return m_flushable; }
 421
 422     // only for input/output buffers respectively, returns NULL otherwise
 423     wxInputStream *GetInputStream() const;
 424     wxOutputStream *GetOutputStream() const;
 425
 426     // deprecated, for compatibility only
 427     wxStreamBase *Stream() { return m_stream; }
 428
 429     // this constructs a dummy wxStreamBuffer, used by (and exists for)
 430     // wxMemoryStreams only, don't use!
 431     wxStreamBuffer(BufMode mode);
 432
 433 protected:
 434     void GetFromBuffer(void *buffer, size_t size);
 435     void PutToBuffer(const void *buffer, size_t size);
 436
 437     // set the last error to the specified value if we didn't have it before
 438     void SetError(wxStreamError err);
 439
 440     // common part of several ctors
 441     void Init();
 442
 443     // init buffer variables to be empty
 444     void InitBuffer();
 445
 446     // free the buffer (always safe to call)
 447     void FreeBuffer();
 448
 449     // the buffer itself: the pointers to its start and end and the current
 450     // position in the buffer
 451     char *m_buffer_start,
 452          *m_buffer_end,
 453          *m_buffer_pos;
 454
 455     // the buffer size
 456     // FIXME: isn't it the same as m_buffer_end - m_buffer_start? (VZ)
 457     size_t m_buffer_size;
 458
 459     // the stream we're associated with
 460     wxStreamBase *m_stream;
 461
 462     // its mode
 463     BufMode m_mode;
 464
 465     // flags
 466     bool m_destroybuf,      // deallocate buffer?
 467          m_fixed,
 468          m_flushable;
 469
 470 private:
 471 // Cannot use
 472 //  DECLARE_NO_COPY_CLASS(wxStreamBuffer)
 473 // because copy constructor is explicitly declared above;
 474 // but no copy assignment operator is defined, so declare
 475 // it private to prevent the compiler from defining it:
 476     wxStreamBuffer& operator=(const wxStreamBuffer&);
 477 };
 478
 479 // ---------------------------------------------------------------------------
 480 // wxBufferedInputStream
 481 // ---------------------------------------------------------------------------
 482
 483 class WXDLLIMPEXP_BASE wxBufferedInputStream : public wxFilterInputStream
 484 {
 485 public:
 486     // if a non NULL buffer is given to the stream, it will be deleted by it
 487     wxBufferedInputStream(wxInputStream& stream,
 488                           wxStreamBuffer *buffer = NULL);
 489     virtual ~wxBufferedInputStream();
 490
 491     char Peek();
 492     wxInputStream& Read(void *buffer, size_t size);
 493
 494     // Position functions
 495     wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 496     wxFileOffset TellI() const;
 497     bool IsSeekable() const { return m_parent_i_stream->IsSeekable(); }
 498
 499     // the buffer given to the stream will be deleted by it
 500     void SetInputStreamBuffer(wxStreamBuffer *buffer);
 501     wxStreamBuffer *GetInputStreamBuffer() const { return m_i_streambuf; }
 502
 503     // deprecated, for compatibility only
 504     wxStreamBuffer *InputStreamBuffer() const { return m_i_streambuf; }
 505
 506 protected:
 507     virtual size_t OnSysRead(void *buffer, size_t bufsize);
 508     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 509     virtual wxFileOffset OnSysTell() const;
 510
 511     wxStreamBuffer *m_i_streambuf;
 512
 513     DECLARE_NO_COPY_CLASS(wxBufferedInputStream)
 514 };
 515
 516 // ----------------------------------------------------------------------------
 517 // wxBufferedOutputStream
 518 // ----------------------------------------------------------------------------
 519
 520 class WXDLLIMPEXP_BASE wxBufferedOutputStream : public wxFilterOutputStream
 521 {
 522 public:
 523     // if a non NULL buffer is given to the stream, it will be deleted by it
 524     wxBufferedOutputStream(wxOutputStream& stream,
 525                            wxStreamBuffer *buffer = NULL);
 526     virtual ~wxBufferedOutputStream();
 527
 528     wxOutputStream& Write(const void *buffer, size_t size);
 529
 530     // Position functions
 531     wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 532     wxFileOffset TellO() const;
 533     bool IsSeekable() const { return m_parent_o_stream->IsSeekable(); }
 534
 535     void Sync();
 536     bool Close();
 537
 538     wxFileOffset GetLength() const;
 539
 540     // the buffer given to the stream will be deleted by it
 541     void SetOutputStreamBuffer(wxStreamBuffer *buffer);
 542     wxStreamBuffer *GetOutputStreamBuffer() const { return m_o_streambuf; }
 543
 544     // deprecated, for compatibility only
 545     wxStreamBuffer *OutputStreamBuffer() const { return m_o_streambuf; }
 546
 547 protected:
 548     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 549     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 550     virtual wxFileOffset OnSysTell() const;
 551
 552     wxStreamBuffer *m_o_streambuf;
 553
 554     DECLARE_NO_COPY_CLASS(wxBufferedOutputStream)
 555 };
 556
 557 #endif // wxUSE_STREAMS
 558
 559 #endif // _WX_WXSTREAM_H__
 560