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 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 true; }
 270
 271 protected:
 272     virtual size_t OnSysWrite(const void *buffer, size_t size);
 273     virtual wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode);
 274     virtual wxFileOffset OnSysTell() const;
 275
 276     size_t m_currentPos;
 277
 278     DECLARE_NO_COPY_CLASS(wxCountingOutputStream)
 279 };
 280
 281 // ---------------------------------------------------------------------------
 282 // "Filter" streams
 283 // ---------------------------------------------------------------------------
 284
 285 class WXDLLIMPEXP_BASE wxFilterInputStream : public wxInputStream
 286 {
 287 public:
 288     wxFilterInputStream();
 289     wxFilterInputStream(wxInputStream& stream);
 290     virtual ~wxFilterInputStream();
 291
 292     char Peek() { return m_parent_i_stream->Peek(); }
 293
 294     wxFileOffset GetLength() const { return m_parent_i_stream->GetLength(); }
 295
 296     wxInputStream *GetFilterInputStream() const { return m_parent_i_stream; }
 297
 298 protected:
 299     wxInputStream *m_parent_i_stream;
 300
 301     DECLARE_NO_COPY_CLASS(wxFilterInputStream)
 302 };
 303
 304 class WXDLLIMPEXP_BASE wxFilterOutputStream : public wxOutputStream
 305 {
 306 public:
 307     wxFilterOutputStream();
 308     wxFilterOutputStream(wxOutputStream& stream);
 309     virtual ~wxFilterOutputStream();
 310
 311     wxFileOffset GetLength() const { return m_parent_o_stream->GetLength(); }
 312
 313     wxOutputStream *GetFilterOutputStream() const { return m_parent_o_stream; }
 314
 315 protected:
 316     wxOutputStream *m_parent_o_stream;
 317
 318     DECLARE_NO_COPY_CLASS(wxFilterOutputStream)
 319 };
 320
 321 // ============================================================================
 322 // buffered streams
 323 // ============================================================================
 324
 325 // ---------------------------------------------------------------------------
 326 // Stream buffer: this class can be derived from and passed to
 327 // wxBufferedStreams to implement custom buffering
 328 // ---------------------------------------------------------------------------
 329
 330 class WXDLLIMPEXP_BASE wxStreamBuffer
 331 {
 332 public:
 333     enum BufMode
 334     {
 335         read,
 336         write,
 337         read_write
 338     };
 339
 340     wxStreamBuffer(wxStreamBase& stream, BufMode mode);
 341     wxStreamBuffer(const wxStreamBuffer& buf);
 342     virtual ~wxStreamBuffer();
 343
 344     // Filtered IO
 345     virtual size_t Read(void *buffer, size_t size);
 346     size_t Read(wxStreamBuffer *buf);
 347     virtual size_t Write(const void *buffer, size_t size);
 348     size_t Write(wxStreamBuffer *buf);
 349
 350     virtual char Peek();
 351     virtual char GetChar();
 352     virtual void PutChar(char c);
 353     virtual wxFileOffset Tell() const;
 354     virtual wxFileOffset Seek(wxFileOffset pos, wxSeekMode mode);
 355
 356     // Buffer control
 357     void ResetBuffer();
 358
 359     // NB: the buffer must always be allocated with malloc() if takeOwn is
 360     //     true as it will be deallocated by free()
 361     void SetBufferIO(void *start, void *end, bool takeOwnership = false);
 362     void SetBufferIO(void *start, size_t len, bool takeOwnership = false);
 363     void SetBufferIO(size_t bufsize);
 364     void *GetBufferStart() const { return m_buffer_start; }
 365     void *GetBufferEnd() const { return m_buffer_end; }
 366     void *GetBufferPos() const { return m_buffer_pos; }
 367     size_t GetBufferSize() const { return m_buffer_size; }
 368     size_t GetIntPosition() const { return m_buffer_pos - m_buffer_start; }
 369     void SetIntPosition(size_t pos) { m_buffer_pos = m_buffer_start + pos; }
 370     size_t GetLastAccess() const { return m_buffer_end - m_buffer_start; }
 371     size_t GetBytesLeft() const { return m_buffer_end - m_buffer_pos; }
 372
 373     void Fixed(bool fixed) { m_fixed = fixed; }
 374     void Flushable(bool f) { m_flushable = f; }
 375
 376     bool FlushBuffer();
 377     bool FillBuffer();
 378     size_t GetDataLeft();
 379
 380     // misc accessors
 381     wxStreamBase *GetStream() const { return m_stream; }
 382     bool HasBuffer() const { return m_buffer_size != 0; }
 383
 384     bool IsFixed() const { return m_fixed; }
 385     bool IsFlushable() const { return m_flushable; }
 386
 387     // only for input/output buffers respectively, returns NULL otherwise
 388     wxInputStream *GetInputStream() const;
 389     wxOutputStream *GetOutputStream() const;
 390
 391     // deprecated, for compatibility only
 392     wxStreamBase *Stream() { return m_stream; }
 393
 394     // this constructs a dummy wxStreamBuffer, used by (and exists for)
 395     // wxMemoryStreams only, don't use!
 396     wxStreamBuffer(BufMode mode);
 397
 398 protected:
 399     void GetFromBuffer(void *buffer, size_t size);
 400     void PutToBuffer(const void *buffer, size_t size);
 401
 402     // set the last error to the specified value if we didn't have it before
 403     void SetError(wxStreamError err);
 404
 405     // common part of several ctors
 406     void Init();
 407
 408     // init buffer variables to be empty
 409     void InitBuffer();
 410
 411     // free the buffer (always safe to call)
 412     void FreeBuffer();
 413
 414     // the buffer itself: the pointers to its start and end and the current
 415     // position in the buffer
 416     char *m_buffer_start,
 417          *m_buffer_end,
 418          *m_buffer_pos;
 419
 420     // the buffer size
 421     // FIXME: isn't it the same as m_buffer_end - m_buffer_start? (VZ)
 422     size_t m_buffer_size;
 423
 424     // the stream we're associated with
 425     wxStreamBase *m_stream;
 426
 427     // its mode
 428     BufMode m_mode;
 429
 430     // flags
 431     bool m_destroybuf,      // deallocate buffer?
 432          m_fixed,
 433          m_flushable;
 434
 435 private:
 436 // Cannot use
 437 //  DECLARE_NO_COPY_CLASS(wxStreamBuffer)
 438 // because copy constructor is explicitly declared above;
 439 // but no copy assignment operator is defined, so declare
 440 // it private to prevent the compiler from defining it:
 441     wxStreamBuffer& operator=(const wxStreamBuffer&);
 442 };
 443
 444 // ---------------------------------------------------------------------------
 445 // wxBufferedInputStream
 446 // ---------------------------------------------------------------------------
 447
 448 class WXDLLIMPEXP_BASE wxBufferedInputStream : public wxFilterInputStream
 449 {
 450 public:
 451     // if a non NULL buffer is given to the stream, it will be deleted by it
 452     wxBufferedInputStream(wxInputStream& stream,
 453                           wxStreamBuffer *buffer = NULL);
 454     virtual ~wxBufferedInputStream();
 455
 456     char Peek();
 457     wxInputStream& Read(void *buffer, size_t size);
 458
 459     // Position functions
 460     wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 461     wxFileOffset TellI() const;
 462     bool IsSeekable() const { return m_parent_i_stream->IsSeekable(); }
 463
 464     // the buffer given to the stream will be deleted by it
 465     void SetInputStreamBuffer(wxStreamBuffer *buffer);
 466     wxStreamBuffer *GetInputStreamBuffer() const { return m_i_streambuf; }
 467
 468     // deprecated, for compatibility only
 469     wxStreamBuffer *InputStreamBuffer() const { return m_i_streambuf; }
 470
 471 protected:
 472     virtual size_t OnSysRead(void *buffer, size_t bufsize);
 473     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 474     virtual wxFileOffset OnSysTell() const;
 475
 476     wxStreamBuffer *m_i_streambuf;
 477
 478     DECLARE_NO_COPY_CLASS(wxBufferedInputStream)
 479 };
 480
 481 // ----------------------------------------------------------------------------
 482 // wxBufferedOutputStream
 483 // ----------------------------------------------------------------------------
 484
 485 class WXDLLIMPEXP_BASE wxBufferedOutputStream : public wxFilterOutputStream
 486 {
 487 public:
 488     // if a non NULL buffer is given to the stream, it will be deleted by it
 489     wxBufferedOutputStream(wxOutputStream& stream,
 490                            wxStreamBuffer *buffer = NULL);
 491     virtual ~wxBufferedOutputStream();
 492
 493     wxOutputStream& Write(const void *buffer, size_t size);
 494
 495     // Position functions
 496     wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart);
 497     wxFileOffset TellO() const;
 498     bool IsSeekable() const { return m_parent_o_stream->IsSeekable(); }
 499
 500     void Sync();
 501     bool Close();
 502
 503     wxFileOffset GetLength() const;
 504
 505     // the buffer given to the stream will be deleted by it
 506     void SetOutputStreamBuffer(wxStreamBuffer *buffer);
 507     wxStreamBuffer *GetOutputStreamBuffer() const { return m_o_streambuf; }
 508
 509     // deprecated, for compatibility only
 510     wxStreamBuffer *OutputStreamBuffer() const { return m_o_streambuf; }
 511
 512 protected:
 513     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 514     virtual wxFileOffset OnSysSeek(wxFileOffset seek, wxSeekMode mode);
 515     virtual wxFileOffset OnSysTell() const;
 516
 517     wxStreamBuffer *m_o_streambuf;
 518
 519     DECLARE_NO_COPY_CLASS(wxBufferedOutputStream)
 520 };
 521
 522 #endif // wxUSE_STREAMS
 523
 524 #endif // _WX_WXSTREAM_H__
 525