| 1 | ///////////////////////////////////////////////////////////////////////////// |
| 2 | // Name: include/wx/private/fileback.h |
| 3 | // Purpose: Back an input stream with memory or a file |
| 4 | // Author: Mike Wetherell |
| 5 | // RCS-ID: $Id$ |
| 6 | // Copyright: (c) 2006 Mike Wetherell |
| 7 | // Licence: wxWindows licence |
| 8 | ///////////////////////////////////////////////////////////////////////////// |
| 9 | |
| 10 | #ifndef _WX_FILEBACK_H__ |
| 11 | #define _WX_FILEBACK_H__ |
| 12 | |
| 13 | #include "wx/defs.h" |
| 14 | |
| 15 | #if wxUSE_FILESYSTEM |
| 16 | |
| 17 | #include "wx/stream.h" |
| 18 | |
| 19 | // ---------------------------------------------------------------------------- |
| 20 | // Backs an input stream with memory or a file to make it seekable. |
| 21 | // |
| 22 | // One or more wxBackedInputStreams can be used to read it's data. The data is |
| 23 | // reference counted, so stays alive until the last wxBackingFile or |
| 24 | // wxBackedInputStream using it is destroyed. |
| 25 | // ---------------------------------------------------------------------------- |
| 26 | |
| 27 | class WXDLLIMPEXP_BASE wxBackingFile |
| 28 | { |
| 29 | public: |
| 30 | enum { DefaultBufSize = 16384 }; |
| 31 | |
| 32 | // Takes ownership of stream. If the stream is smaller than bufsize, the |
| 33 | // backing file is never created and the backing is done with memory. |
| 34 | wxBackingFile(wxInputStream *stream, |
| 35 | size_t bufsize = DefaultBufSize, |
| 36 | const wxString& prefix = _T("wxbf")); |
| 37 | |
| 38 | wxBackingFile() : m_impl(NULL) { } |
| 39 | ~wxBackingFile(); |
| 40 | |
| 41 | wxBackingFile(const wxBackingFile& backer); |
| 42 | wxBackingFile& operator=(const wxBackingFile& backer); |
| 43 | |
| 44 | operator bool() const { return m_impl != NULL; } |
| 45 | |
| 46 | private: |
| 47 | class wxBackingFileImpl *m_impl; |
| 48 | friend class wxBackedInputStream; |
| 49 | }; |
| 50 | |
| 51 | // ---------------------------------------------------------------------------- |
| 52 | // An input stream to read from a wxBackingFile. |
| 53 | // ---------------------------------------------------------------------------- |
| 54 | |
| 55 | class WXDLLIMPEXP_BASE wxBackedInputStream : public wxInputStream |
| 56 | { |
| 57 | public: |
| 58 | wxBackedInputStream(const wxBackingFile& backer); |
| 59 | |
| 60 | // If the length of the backer's parent stream is unknown then GetLength() |
| 61 | // returns wxInvalidOffset until the parent has been read to the end. |
| 62 | wxFileOffset GetLength() const; |
| 63 | |
| 64 | // Returns the length, reading the parent stream to the end if necessary. |
| 65 | wxFileOffset FindLength() const; |
| 66 | |
| 67 | bool IsSeekable() const { return true; } |
| 68 | |
| 69 | protected: |
| 70 | size_t OnSysRead(void *buffer, size_t size); |
| 71 | wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode); |
| 72 | wxFileOffset OnSysTell() const; |
| 73 | |
| 74 | private: |
| 75 | wxBackingFile m_backer; |
| 76 | wxFileOffset m_pos; |
| 77 | |
| 78 | DECLARE_NO_COPY_CLASS(wxBackedInputStream) |
| 79 | }; |
| 80 | |
| 81 | #endif // wxUSE_FILESYSTEM |
| 82 | |
| 83 | #endif // _WX_FILEBACK_H__ |