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