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 // ============================================================================
  46 // base stream classes: wxInputStream and wxOutputStream
  47 // ============================================================================
  48
  49 // ---------------------------------------------------------------------------
  50 // wxStreamBase: common (but non virtual!) base for all stream classes
  51 // ---------------------------------------------------------------------------
  52
  53 class WXDLLIMPEXP_BASE wxStreamBase
  54 {
  55 public:
  56     wxStreamBase();
  57     virtual ~wxStreamBase();
  58
  59     // error testing
  60     wxStreamError GetLastError() const { return m_lasterror; }
  61     virtual bool IsOk() const { return GetLastError() == wxSTREAM_NO_ERROR; }
  62     bool operator!() const { return !IsOk(); }
  63
  64     // reset the stream state
  65     void Reset() { m_lasterror = wxSTREAM_NO_ERROR; }
  66
  67     // this doesn't make sense for all streams, always test its return value
  68     virtual size_t GetSize() const;
  69     virtual wxFileOffset GetLength() const { return wxInvalidOffset; }
  70
  71     // returns true if the streams supports seeking to arbitrary offsets
  72     virtual bool IsSeekable() const { return false; }
  73
  74 protected:
  75     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
  76     virtual wxFileOffset OnSysTell() const;
  77
  78     size_t m_lastcount;
  79     wxStreamError m_lasterror;
  80
  81     friend class wxStreamBuffer;
  82
  83     DECLARE_NO_COPY_CLASS(wxStreamBase)
  84 };
  85
  86 // ----------------------------------------------------------------------------
  87 // wxInputStream: base class for the input streams
  88 // ----------------------------------------------------------------------------
  89
  90 class WXDLLIMPEXP_BASE wxInputStream : public wxStreamBase
  91 {
  92 public:
  93     // ctor and dtor, nothing exciting
  94     wxInputStream();
  95     virtual ~wxInputStream();
  96
  97
  98     // IO functions
  99     // ------------
 100
 101     // return a character from the stream without removing it, i.e. it will
 102     // still be returned by the next call to GetC()
 103     //
 104     // blocks until something appears in the stream if necessary, if nothing
 105     // ever does (i.e. EOF) LastRead() will return 0 (and the return value is
 106     // undefined), otherwise 1
 107     virtual char Peek();
 108
 109     // return one character from the stream, blocking until it appears if
 110     // necessary
 111     //
 112     // if EOF, return value is undefined and LastRead() will return 0 and not 1
 113     char GetC();
 114
 115     // read at most the given number of bytes from the stream
 116     //
 117     // there are 2 possible situations here: either there is nothing at all in
 118     // the stream right now in which case Read() blocks until something appears
 119     // (use CanRead() to avoid this) or there is already some data available in
 120     // the stream and then Read() doesn't block but returns just the data it
 121     // can read without waiting for more
 122     //
 123     // in any case, if there are not enough bytes in the stream right now,
 124     // LastRead() value will be less than size but greater than 0. If it is 0,
 125     // it means that EOF has been reached.
 126     virtual wxInputStream& Read(void *buffer, size_t size);
 127
 128     // copy the entire contents of this stream into streamOut, stopping only
 129     // when EOF is reached or an error occurs
 130     wxInputStream& Read(wxOutputStream& streamOut);
 131
 132
 133     // status functions
 134     // ----------------
 135
 136     // returns the number of bytes read by the last call to Read(), GetC() or
 137     // Peek()
 138     //
 139     // this should be used to discover whether that call succeeded in reading
 140     // all the requested data or not
 141     virtual size_t LastRead() const { return wxStreamBase::m_lastcount; }
 142
 143     // returns true if some data is available in the stream right now, so that
 144     // calling Read() wouldn't block
 145     virtual bool CanRead() const;
 146
 147     // is the stream at EOF?
 148     //
 149     // note that this cannot be really implemented for all streams and
 150     // CanRead() is more reliable than Eof()
 151     virtual bool Eof() const;
 152
 153
 154     // write back buffer
 155     // -----------------
 156
 157     // put back the specified number of bytes into the stream, they will be
 158     // fetched by the next call to the read functions
 159     //
 160     // returns the number of bytes really stuffed back
 161     size_t Ungetch(const void *buffer, size_t size);
 162
 163     // put back the specified character in the stream
 164     //
 165     // returns true if ok, false on error
 166     bool Ungetch(char c);
 167
 168
 169     // position functions
 170     // ------------------
 171
 172     // move the stream pointer to the given position (if the stream supports
 173     // it)
 174     //
 175     // returns wxInvalidOffset on error
 176     virtual wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 177
 178     // return the current position of the stream pointer or wxInvalidOffset
 179     virtual wxFileOffset TellI() const;
 180
 181
 182     // stream-like operators
 183     // ---------------------
 184
 185     wxInputStream& operator>>(wxOutputStream& out) { return Read(out); }
 186     wxInputStream& operator>>(__wxInputManip func) { return func(*this); }
 187
 188 protected:
 189     // do read up to size bytes of data into the provided buffer
 190     //
 191     // this method should return 0 if EOF has been reached or an error occurred
 192     // (m_lasterror should be set accordingly as well) or the number of bytes
 193     // read
 194     virtual size_t OnSysRead(void *buffer, size_t size) = 0;
 195
 196     // write-back buffer support
 197     // -------------------------
 198
 199     // return the pointer to a buffer big enough to hold sizeNeeded bytes
 200     char *AllocSpaceWBack(size_t sizeNeeded);
 201
 202     // read up to size data from the write back buffer, return the number of
 203     // bytes read
 204     size_t GetWBack(void *buf, size_t size);
 205
 206     // write back buffer or NULL if none
 207     char *m_wback;
 208
 209     // the size of the buffer
 210     size_t m_wbacksize;
 211
 212     // the current position in the buffer
 213     size_t m_wbackcur;
 214
 215     friend class wxStreamBuffer;
 216
 217     DECLARE_NO_COPY_CLASS(wxInputStream)
 218 };
 219
 220 // ----------------------------------------------------------------------------
 221 // wxOutputStream: base for the output streams
 222 // ----------------------------------------------------------------------------
 223
 224 class WXDLLIMPEXP_BASE wxOutputStream : public wxStreamBase
 225 {
 226 public:
 227     wxOutputStream();
 228     virtual ~wxOutputStream();
 229
 230     void PutC(char c);
 231     virtual wxOutputStream& Write(const void *buffer, size_t size);
 232     wxOutputStream& Write(wxInputStream& stream_in);
 233
 234     virtual wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 235     virtual wxFileOffset TellO() const;
 236
 237     virtual size_t LastWrite() const { return wxStreamBase::m_lastcount; }
 238
 239     virtual void Sync();
 240     virtual bool Close() { return true; }
 241
 242     wxOutputStream& operator<<(wxInputStream& out) { return Write(out); }
 243     wxOutputStream& operator<<( __wxOutputManip func) { return func(*this); }
 244
 245 protected:
 246     // to be implemented in the derived classes (it should have been pure
 247     // virtual)
 248     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 249
 250     friend class wxStreamBuffer;
 251
 252     DECLARE_NO_COPY_CLASS(wxOutputStream)
 253 };
 254
 255 // ============================================================================
 256 // helper stream classes
 257 // ============================================================================
 258
 259 // ---------------------------------------------------------------------------
 260 // A stream for measuring streamed output
 261 // ---------------------------------------------------------------------------
 262
 263 class WXDLLIMPEXP_BASE wxCountingOutputStream : public wxOutputStream
 264 {
 265 public:
 266     wxCountingOutputStream();
 267
 268     wxFileOffset GetLength() const;
 269     bool Ok() const { return IsOk(); }
 270     bool IsOk() const { return true; }
 271
 272 protected:
 273     virtual size_t OnSysWrite(const void *buffer, size_t size);
 274     virtual wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode);
 275     virtual wxFileOffset OnSysTell() const;
 276
 277     size_t m_currentPos;
 278
 279     DECLARE_NO_COPY_CLASS(wxCountingOutputStream)
 280 };
 281
 282 // ---------------------------------------------------------------------------
 283 // "Filter" streams
 284 // ---------------------------------------------------------------------------
 285
 286 class WXDLLIMPEXP_BASE wxFilterInputStream : public wxInputStream
 287 {
 288 public:
 289     wxFilterInputStream();
 290     wxFilterInputStream(wxInputStream& stream);
 291     virtual ~wxFilterInputStream();
 292
 293     char Peek() { return m_parent_i_stream->Peek(); }
 294
 295     wxFileOffset GetLength() const { return m_parent_i_stream->GetLength(); }
 296
 297     wxInputStream *GetFilterInputStream() const { return m_parent_i_stream; }
 298
 299 protected:
 300     wxInputStream *m_parent_i_stream;
 301
 302     DECLARE_NO_COPY_CLASS(wxFilterInputStream)
 303 };
 304
 305 class WXDLLIMPEXP_BASE wxFilterOutputStream : public wxOutputStream
 306 {
 307 public:
 308     wxFilterOutputStream();
 309     wxFilterOutputStream(wxOutputStream& stream);
 310     virtual ~wxFilterOutputStream();
 311
 312     wxFileOffset GetLength() const { return m_parent_o_stream->GetLength(); }
 313
 314     wxOutputStream *GetFilterOutputStream() const { return m_parent_o_stream; }
 315
 316 protected:
 317     wxOutputStream *m_parent_o_stream;
 318
 319     DECLARE_NO_COPY_CLASS(wxFilterOutputStream)
 320 };
 321
 322 // ============================================================================
 323 // buffered streams
 324 // ============================================================================
 325
 326 // ---------------------------------------------------------------------------
 327 // Stream buffer: this class can be derived from and passed to
 328 // wxBufferedStreams to implement custom buffering
 329 // ---------------------------------------------------------------------------
 330
 331 class WXDLLIMPEXP_BASE wxStreamBuffer
 332 {
 333 public:
 334     enum BufMode
 335     {
 336         read,
 337         write,
 338         read_write
 339     };
 340
 341     wxStreamBuffer(wxStreamBase& stream, BufMode mode);
 342     wxStreamBuffer(const wxStreamBuffer& buf);
 343     virtual ~wxStreamBuffer();
 344
 345     // Filtered IO
 346     virtual size_t Read(void *buffer, size_t size);
 347     size_t Read(wxStreamBuffer *buf);
 348     virtual size_t Write(const void *buffer, size_t size);
 349     size_t Write(wxStreamBuffer *buf);
 350
 351     virtual char Peek();
 352     virtual char GetChar();
 353     virtual void PutChar(char c);
 354     virtual wxFileOffset Tell() const;
 355     virtual wxFileOffset Seek(wxFileOffset pos, wxSeekMode mode);
 356
 357     // Buffer control
 358     void ResetBuffer();
 359
 360     // NB: the buffer must always be allocated with malloc() if takeOwn is
 361     //     true as it will be deallocated by free()
 362     void SetBufferIO(void *start, void *end, bool takeOwnership = false);
 363     void SetBufferIO(void *start, size_t len, bool takeOwnership = false);
 364     void SetBufferIO(size_t bufsize);
 365     void *GetBufferStart() const { return m_buffer_start; }
 366     void *GetBufferEnd() const { return m_buffer_end; }
 367     void *GetBufferPos() const { return m_buffer_pos; }
 368     size_t GetBufferSize() const { return m_buffer_size; }
 369     size_t GetIntPosition() const { return m_buffer_pos - m_buffer_start; }
 370     void SetIntPosition(size_t pos) { m_buffer_pos = m_buffer_start + pos; }
 371     size_t GetLastAccess() const { return m_buffer_end - m_buffer_start; }
 372     size_t GetBytesLeft() const { return m_buffer_end - m_buffer_pos; }
 373
 374     void Fixed(bool fixed) { m_fixed = fixed; }
 375     void Flushable(bool f) { m_flushable = f; }
 376
 377     bool FlushBuffer();
 378     bool FillBuffer();
 379     size_t GetDataLeft();
 380
 381     // misc accessors
 382     wxStreamBase *GetStream() const { return m_stream; }
 383     bool HasBuffer() const { return m_buffer_size != 0; }
 384
 385     bool IsFixed() const { return m_fixed; }
 386     bool IsFlushable() const { return m_flushable; }
 387
 388     // only for input/output buffers respectively, returns NULL otherwise
 389     wxInputStream *GetInputStream() const;
 390     wxOutputStream *GetOutputStream() const;
 391
 392 #if WXWIN_COMPATIBILITY_2_6
 393     // deprecated, for compatibility only
 394     wxDEPRECATED( wxStreamBase *Stream() );
 395 #endif // WXWIN_COMPATIBILITY_2_6
 396
 397     // this constructs a dummy wxStreamBuffer, used by (and exists for)
 398     // wxMemoryStreams only, don't use!
 399     wxStreamBuffer(BufMode mode);
 400
 401 protected:
 402     void GetFromBuffer(void *buffer, size_t size);
 403     void PutToBuffer(const void *buffer, size_t size);
 404
 405     // set the last error to the specified value if we didn't have it before
 406     void SetError(wxStreamError err);
 407
 408     // common part of several ctors
 409     void Init();
 410
 411     // init buffer variables to be empty
 412     void InitBuffer();
 413
 414     // free the buffer (always safe to call)
 415     void FreeBuffer();
 416
 417     // the buffer itself: the pointers to its start and end and the current
 418     // position in the buffer
 419     char *m_buffer_start,
 420          *m_buffer_end,
 421          *m_buffer_pos;
 422
 423     // the buffer size
 424     // FIXME: isn't it the same as m_buffer_end - m_buffer_start? (VZ)
 425     size_t m_buffer_size;
 426
 427     // the stream we're associated with
 428     wxStreamBase *m_stream;
 429
 430     // its mode
 431     BufMode m_mode;
 432
 433     // flags
 434     bool m_destroybuf,      // deallocate buffer?
 435          m_fixed,
 436          m_flushable;
 437
 438 private:
 439 // Cannot use
 440 //  DECLARE_NO_COPY_CLASS(wxStreamBuffer)
 441 // because copy constructor is explicitly declared above;
 442 // but no copy assignment operator is defined, so declare
 443 // it private to prevent the compiler from defining it:
 444     wxStreamBuffer& operator=(const wxStreamBuffer&);
 445 };
 446
 447 // ---------------------------------------------------------------------------
 448 // wxBufferedInputStream
 449 // ---------------------------------------------------------------------------
 450
 451 class WXDLLIMPEXP_BASE wxBufferedInputStream : public wxFilterInputStream
 452 {
 453 public:
 454     // if a non NULL buffer is given to the stream, it will be deleted by it
 455     wxBufferedInputStream(wxInputStream& stream,
 456                           wxStreamBuffer *buffer = NULL);
 457     virtual ~wxBufferedInputStream();
 458
 459     char Peek();
 460     wxInputStream& Read(void *buffer, size_t size);
 461
 462     // Position functions
 463     wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 464     wxFileOffset TellI() const;
 465     bool IsSeekable() const { return m_parent_i_stream->IsSeekable(); }
 466
 467     // the buffer given to the stream will be deleted by it
 468     void SetInputStreamBuffer(wxStreamBuffer *buffer);
 469     wxStreamBuffer *GetInputStreamBuffer() const { return m_i_streambuf; }
 470
 471 #if WXWIN_COMPATIBILITY_2_6
 472     // deprecated, for compatibility only
 473     wxDEPRECATED( wxStreamBuffer *InputStreamBuffer() const );
 474 #endif // WXWIN_COMPATIBILITY_2_6
 475
 476 protected:
 477     virtual size_t OnSysRead(void *buffer, size_t bufsize);
 478     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 479     virtual wxFileOffset OnSysTell() const;
 480
 481     wxStreamBuffer *m_i_streambuf;
 482
 483     DECLARE_NO_COPY_CLASS(wxBufferedInputStream)
 484 };
 485
 486 // ----------------------------------------------------------------------------
 487 // wxBufferedOutputStream
 488 // ----------------------------------------------------------------------------
 489
 490 class WXDLLIMPEXP_BASE wxBufferedOutputStream : public wxFilterOutputStream
 491 {
 492 public:
 493     // if a non NULL buffer is given to the stream, it will be deleted by it
 494     wxBufferedOutputStream(wxOutputStream& stream,
 495                            wxStreamBuffer *buffer = NULL);
 496     virtual ~wxBufferedOutputStream();
 497
 498     wxOutputStream& Write(const void *buffer, size_t size);
 499
 500     // Position functions
 501     wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 502     wxFileOffset TellO() const;
 503     bool IsSeekable() const { return m_parent_o_stream->IsSeekable(); }
 504
 505     void Sync();
 506     bool Close();
 507
 508     wxFileOffset GetLength() const;
 509
 510     // the buffer given to the stream will be deleted by it
 511     void SetOutputStreamBuffer(wxStreamBuffer *buffer);
 512     wxStreamBuffer *GetOutputStreamBuffer() const { return m_o_streambuf; }
 513
 514 #if WXWIN_COMPATIBILITY_2_6
 515     // deprecated, for compatibility only
 516     wxDEPRECATED( wxStreamBuffer *OutputStreamBuffer() const );
 517 #endif // WXWIN_COMPATIBILITY_2_6
 518
 519 protected:
 520     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 521     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 522     virtual wxFileOffset OnSysTell() const;
 523
 524     wxStreamBuffer *m_o_streambuf;
 525
 526     DECLARE_NO_COPY_CLASS(wxBufferedOutputStream)
 527 };
 528
 529 #if WXWIN_COMPATIBILITY_2_6
 530     inline wxStreamBase *wxStreamBuffer::Stream() { return m_stream; }
 531     inline wxStreamBuffer *wxBufferedInputStream::InputStreamBuffer() const { return m_i_streambuf; }
 532     inline wxStreamBuffer *wxBufferedOutputStream::OutputStreamBuffer() const { return m_o_streambuf; }
 533 #endif // WXWIN_COMPATIBILITY_2_6
 534
 535 #endif // wxUSE_STREAMS
 536
 537 #endif // _WX_WXSTREAM_H__