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