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 license
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_WXSTREAM_H__
  13 #define _WX_WXSTREAM_H__
  14
  15 #if defined(__GNUG__) && !defined(__APPLE__)
  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 off_t, wxInvalidOffset and wxSeekMode
  27
  28 class WXDLLEXPORT wxStreamBase;
  29 class WXDLLEXPORT wxInputStream;
  30 class WXDLLEXPORT wxOutputStream;
  31
  32 typedef wxInputStream& (*__wxInputManip)(wxInputStream&);
  33 typedef wxOutputStream& (*__wxOutputManip)(wxOutputStream&);
  34
  35 WXDLLEXPORT 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 WXDLLEXPORT 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     // deprecated (doesn't make sense!), don't use
  85     virtual size_t GetSize() const { return 0; }
  86
  87 #if WXWIN_COMPATIBILITY_2_2
  88     // deprecated, for compatibility only
  89     wxStreamError LastError() const { return m_lasterror; }
  90     size_t StreamSize() const { return GetSize(); }
  91 #endif // WXWIN_COMPATIBILITY_2_2
  92
  93 protected:
  94     virtual off_t OnSysSeek(off_t seek, wxSeekMode mode);
  95     virtual off_t OnSysTell() const;
  96
  97     size_t m_lastcount;
  98     wxStreamError m_lasterror;
  99
 100     friend class wxStreamBuffer;
 101 };
 102
 103 // ----------------------------------------------------------------------------
 104 // wxInputStream: base class for the input streams
 105 // ----------------------------------------------------------------------------
 106
 107 class WXDLLEXPORT wxInputStream : public wxStreamBase
 108 {
 109 public:
 110     // ctor and dtor, nothing exciting
 111     wxInputStream();
 112     virtual ~wxInputStream();
 113
 114
 115     // IO functions
 116     // ------------
 117
 118     // return a character from the stream without removing it, i.e. it will
 119     // still be returned by the next call to GetC()
 120     //
 121     // blocks until something appears in the stream if necessary, if nothing
 122     // ever does (i.e. EOF) LastRead() will return 0 (and the return value is
 123     // undefined), otherwise 1
 124     virtual char Peek();
 125
 126     // return one character from the stream, blocking until it appears if
 127     // necessary
 128     //
 129     // if EOF, return value is undefined and LastRead() will return 0 and not 1
 130     char GetC();
 131
 132     // read at most the given number of bytes from the stream
 133     //
 134     // there are 2 possible situations here: either there is nothing at all in
 135     // the stream right now in which case Read() blocks until something appears
 136     // (use CanRead() to avoid this) or there is already some data available in
 137     // the stream and then Read() doesn't block but returns just the data it
 138     // can read without waiting for more
 139     //
 140     // in any case, if there are not enough bytes in the stream right now,
 141     // LastRead() value will be less than size but greater than 0. If it is 0,
 142     // it means that EOF has been reached.
 143     virtual wxInputStream& Read(void *buffer, size_t size);
 144
 145     // copy the entire contents of this stream into streamOut, stopping only
 146     // when EOF is reached or an error occurs
 147     wxInputStream& Read(wxOutputStream& streamOut);
 148
 149
 150     // status functions
 151     // ----------------
 152
 153     // returns the number of bytes read by the last call to Read(), GetC() or
 154     // Peek()
 155     //
 156     // this should be used to discover whether that call succeeded in reading
 157     // all the requested data or not
 158     virtual size_t LastRead() const { return wxStreamBase::m_lastcount; }
 159
 160     // returns TRUE if some data is available in the stream right now, so that
 161     // calling Read() wouldn't block
 162     virtual bool CanRead() const;
 163
 164     // is the stream at EOF?
 165     //
 166     // note that this cannot be really implemented for all streams and
 167     // CanRead() is more reliable than Eof()
 168     virtual bool Eof() const;
 169
 170
 171     // write back buffer
 172     // -----------------
 173
 174     // put back the specified number of bytes into the stream, they will be
 175     // fetched by the next call to the read functions
 176     //
 177     // returns the number of bytes really stuffed back
 178     size_t Ungetch(const void *buffer, size_t size);
 179
 180     // put back the specified character in the stream
 181     //
 182     // returns TRUE if ok, FALSE on error
 183     bool Ungetch(char c);
 184
 185
 186     // position functions
 187     // ------------------
 188
 189     // move the stream pointer to the given position (if the stream supports
 190     // it)
 191     //
 192     // returns wxInvalidOffset on error
 193     virtual off_t SeekI(off_t pos, wxSeekMode mode = wxFromStart);
 194
 195     // return the current position of the stream pointer or wxInvalidOffset
 196     virtual off_t TellI() const;
 197
 198
 199     // stream-like operators
 200     // ---------------------
 201
 202     wxInputStream& operator>>(wxOutputStream& out) { return Read(out); }
 203     wxInputStream& operator>>(__wxInputManip func) { return func(*this); }
 204
 205 protected:
 206     // do read up to size bytes of data into the provided buffer
 207     //
 208     // this method should return 0 if EOF has been reached or an error occured
 209     // (m_lasterror should be set accordingly as well) or the number of bytes
 210     // read
 211     virtual size_t OnSysRead(void *buffer, size_t size) = 0;
 212
 213     // write-back buffer support
 214     // -------------------------
 215
 216     // return the pointer to a buffer big enough to hold sizeNeeded bytes
 217     char *AllocSpaceWBack(size_t sizeNeeded);
 218
 219     // read up to size data from the write back buffer, return the number of
 220     // bytes read
 221     size_t GetWBack(void *buf, size_t size);
 222
 223     // write back buffer or NULL if none
 224     char *m_wback;
 225
 226     // the size of the buffer
 227     size_t m_wbacksize;
 228
 229     // the current position in the buffer
 230     size_t m_wbackcur;
 231
 232     friend class wxStreamBuffer;
 233 };
 234
 235 // ----------------------------------------------------------------------------
 236 // wxOutputStream: base for the output streams
 237 // ----------------------------------------------------------------------------
 238
 239 class WXDLLEXPORT wxOutputStream : public wxStreamBase
 240 {
 241 public:
 242     wxOutputStream();
 243     virtual ~wxOutputStream();
 244
 245     void PutC(char c);
 246     virtual wxOutputStream& Write(const void *buffer, size_t size);
 247     wxOutputStream& Write(wxInputStream& stream_in);
 248
 249     virtual off_t SeekO(off_t pos, wxSeekMode mode = wxFromStart);
 250     virtual off_t TellO() const;
 251
 252     virtual size_t LastWrite() const { return wxStreamBase::m_lastcount; }
 253
 254     virtual void Sync();
 255
 256     wxOutputStream& operator<<(wxInputStream& out) { return Write(out); }
 257     wxOutputStream& operator<<( __wxOutputManip func) { return func(*this); }
 258
 259 protected:
 260     // to be implemented in the derived classes (it should have been pure
 261     // virtual)
 262     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 263
 264     friend class wxStreamBuffer;
 265 };
 266
 267 // ============================================================================
 268 // helper stream classes
 269 // ============================================================================
 270
 271 // ---------------------------------------------------------------------------
 272 // A stream for measuring streamed output
 273 // ---------------------------------------------------------------------------
 274
 275 class WXDLLEXPORT wxCountingOutputStream : public wxOutputStream
 276 {
 277 public:
 278     wxCountingOutputStream();
 279
 280     size_t GetSize() const;
 281     bool Ok() const { return TRUE; }
 282
 283 protected:
 284     virtual size_t OnSysWrite(const void *buffer, size_t size);
 285     virtual off_t OnSysSeek(off_t pos, wxSeekMode mode);
 286     virtual off_t OnSysTell() const;
 287
 288     size_t m_currentPos;
 289 };
 290
 291 // ---------------------------------------------------------------------------
 292 // "Filter" streams
 293 // ---------------------------------------------------------------------------
 294
 295 class WXDLLEXPORT wxFilterInputStream : public wxInputStream
 296 {
 297 public:
 298     wxFilterInputStream();
 299     wxFilterInputStream(wxInputStream& stream);
 300     virtual ~wxFilterInputStream();
 301
 302     char Peek() { return m_parent_i_stream->Peek(); }
 303
 304     size_t GetSize() const { return m_parent_i_stream->GetSize(); }
 305
 306     wxInputStream *GetFilterInputStream() const { return m_parent_i_stream; }
 307
 308 protected:
 309     wxInputStream *m_parent_i_stream;
 310 };
 311
 312 class WXDLLEXPORT wxFilterOutputStream : public wxOutputStream
 313 {
 314 public:
 315     wxFilterOutputStream();
 316     wxFilterOutputStream(wxOutputStream& stream);
 317     virtual ~wxFilterOutputStream();
 318
 319     size_t GetSize() const { return m_parent_o_stream->GetSize(); }
 320
 321     wxOutputStream *GetFilterOutputStream() const { return m_parent_o_stream; }
 322
 323 protected:
 324     wxOutputStream *m_parent_o_stream;
 325 };
 326
 327 // ============================================================================
 328 // buffered streams
 329 // ============================================================================
 330
 331 // ---------------------------------------------------------------------------
 332 // Stream buffer: this class can be derived from and passed to
 333 // wxBufferedStreams to implement custom buffering
 334 // ---------------------------------------------------------------------------
 335
 336 class WXDLLEXPORT wxStreamBuffer
 337 {
 338 public:
 339     enum BufMode
 340     {
 341         read,
 342         write,
 343         read_write
 344     };
 345
 346     wxStreamBuffer(wxStreamBase& stream, BufMode mode);
 347     wxStreamBuffer(const wxStreamBuffer& buf);
 348     virtual ~wxStreamBuffer();
 349
 350     // Filtered IO
 351     virtual size_t Read(void *buffer, size_t size);
 352     size_t Read(wxStreamBuffer *buf);
 353     virtual size_t Write(const void *buffer, size_t size);
 354     size_t Write(wxStreamBuffer *buf);
 355
 356     virtual char Peek();
 357     virtual char GetChar();
 358     virtual void PutChar(char c);
 359     virtual off_t Tell() const;
 360     virtual off_t Seek(off_t pos, wxSeekMode mode);
 361
 362     // Buffer control
 363     void ResetBuffer();
 364
 365     // NB: the buffer must always be allocated with malloc() if takeOwn is
 366     //     TRUE as it will be deallocated by free()
 367     void SetBufferIO(void *start, void *end, bool takeOwnership = FALSE);
 368     void SetBufferIO(void *start, size_t len, bool takeOwnership = FALSE);
 369     void SetBufferIO(size_t bufsize);
 370     void *GetBufferStart() const { return m_buffer_start; }
 371     void *GetBufferEnd() const { return m_buffer_end; }
 372     void *GetBufferPos() const { return m_buffer_pos; }
 373     size_t GetBufferSize() const { return m_buffer_size; }
 374     size_t GetIntPosition() const { return m_buffer_pos - m_buffer_start; }
 375     void SetIntPosition(size_t pos) { m_buffer_pos = m_buffer_start + pos; }
 376     size_t GetLastAccess() const { return m_buffer_end - m_buffer_start; }
 377     size_t GetBytesLeft() const { return m_buffer_end - m_buffer_pos; }
 378
 379     void Fixed(bool fixed) { m_fixed = fixed; }
 380     void Flushable(bool f) { m_flushable = f; }
 381
 382     bool FlushBuffer();
 383     bool FillBuffer();
 384     size_t GetDataLeft();
 385
 386     // misc accessors
 387     wxStreamBase *GetStream() const { return m_stream; }
 388     bool HasBuffer() const { return m_buffer_size != 0; }
 389
 390     bool IsFixed() const { return m_fixed; }
 391     bool IsFlushable() const { return m_flushable; }
 392
 393     // only for input/output buffers respectively, returns NULL otherwise
 394     wxInputStream *GetInputStream() const;
 395     wxOutputStream *GetOutputStream() const;
 396
 397     // deprecated, for compatibility only
 398     wxStreamBase *Stream() { return m_stream; }
 399
 400     // this constructs a dummy wxStreamBuffer, used by (and exists for)
 401     // wxMemoryStreams only, don't use!
 402     wxStreamBuffer(BufMode mode);
 403
 404 protected:
 405     void GetFromBuffer(void *buffer, size_t size);
 406     void PutToBuffer(const void *buffer, size_t size);
 407
 408     // set the last error to the specified value if we didn't have it before
 409     void SetError(wxStreamError err);
 410
 411     // common part of several ctors
 412     void Init();
 413
 414     // init buffer variables to be empty
 415     void InitBuffer();
 416
 417     // free the buffer (always safe to call)
 418     void FreeBuffer();
 419
 420     // the buffer itself: the pointers to its start and end and the current
 421     // position in the buffer
 422     char *m_buffer_start,
 423          *m_buffer_end,
 424          *m_buffer_pos;
 425
 426     // the buffer size
 427     // FIXME: isn't it the same as m_buffer_end - m_buffer_start? (VZ)
 428     size_t m_buffer_size;
 429
 430     // the stream we're associated with
 431     wxStreamBase *m_stream;
 432
 433     // its mode
 434     BufMode m_mode;
 435
 436     // flags
 437     bool m_destroybuf,      // deallocate buffer?
 438          m_fixed,
 439          m_flushable;
 440 };
 441
 442 // ---------------------------------------------------------------------------
 443 // wxBufferedInputStream
 444 // ---------------------------------------------------------------------------
 445
 446 class WXDLLEXPORT wxBufferedInputStream : public wxFilterInputStream
 447 {
 448 public:
 449     // if a non NULL buffer is given to the stream, it will be deleted by it
 450     wxBufferedInputStream(wxInputStream& stream,
 451                           wxStreamBuffer *buffer = NULL);
 452     virtual ~wxBufferedInputStream();
 453
 454     char Peek();
 455     wxInputStream& Read(void *buffer, size_t size);
 456
 457     // Position functions
 458     off_t SeekI(off_t pos, wxSeekMode mode = wxFromStart);
 459     off_t TellI() const;
 460
 461     // the buffer given to the stream will be deleted by it
 462     void SetInputStreamBuffer(wxStreamBuffer *buffer);
 463     wxStreamBuffer *GetInputStreamBuffer() const { return m_i_streambuf; }
 464
 465     // deprecated, for compatibility only
 466     wxStreamBuffer *InputStreamBuffer() const { return m_i_streambuf; }
 467
 468 protected:
 469     virtual size_t OnSysRead(void *buffer, size_t bufsize);
 470     virtual off_t OnSysSeek(off_t seek, wxSeekMode mode);
 471     virtual off_t OnSysTell() const;
 472
 473     wxStreamBuffer *m_i_streambuf;
 474 };
 475
 476 // ----------------------------------------------------------------------------
 477 // wxBufferedOutputStream
 478 // ----------------------------------------------------------------------------
 479
 480 class WXDLLEXPORT wxBufferedOutputStream : public wxFilterOutputStream
 481 {
 482 public:
 483     // if a non NULL buffer is given to the stream, it will be deleted by it
 484     wxBufferedOutputStream(wxOutputStream& stream,
 485                            wxStreamBuffer *buffer = NULL);
 486     virtual ~wxBufferedOutputStream();
 487
 488     wxOutputStream& Write(const void *buffer, size_t size);
 489
 490     // Position functions
 491     off_t SeekO(off_t pos, wxSeekMode mode = wxFromStart);
 492     off_t TellO() const;
 493
 494     void Sync();
 495
 496     size_t GetSize() const;
 497
 498     // the buffer given to the stream will be deleted by it
 499     void SetOutputStreamBuffer(wxStreamBuffer *buffer);
 500     wxStreamBuffer *GetOutputStreamBuffer() const { return m_o_streambuf; }
 501
 502     // deprecated, for compatibility only
 503     wxStreamBuffer *OutputStreamBuffer() const { return m_o_streambuf; }
 504
 505 protected:
 506     virtual size_t OnSysWrite(const void *buffer, size_t bufsize);
 507     virtual off_t OnSysSeek(off_t seek, wxSeekMode mode);
 508     virtual off_t OnSysTell() const;
 509
 510     wxStreamBuffer *m_o_streambuf;
 511 };
 512
 513 #endif // wxUSE_STREAMS
 514
 515 #endif // _WX_WXSTREAM_H__
 516