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