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