1 //---------------------------------------------------------------------- 2 // This software is part of the Haiku distribution and is covered 3 // by the MIT License. 4 //--------------------------------------------------------------------- 5 /*! 6 \file OffsetFile.h 7 OffsetFile interface declaration. 8 */ 9 10 #ifndef _OFFSET_FILE_H 11 #define _OFFSET_FILE_H 12 13 #include <DataIO.h> 14 #include <File.h> 15 16 namespace BPrivate { 17 namespace Storage { 18 19 /*! 20 \class OffsetFile 21 \brief Provides access to a file skipping a certain amount of bytes at 22 the beginning. 23 24 This class implements the BPositionIO interface to provide access to the 25 data of a file past a certain offset. This is very handy e.g. for dealing 26 with resources, as they always reside at the end of a file, but may start 27 at arbitrary offsets. 28 29 \author <a href='mailto:bonefish@users.sf.net'>Ingo Weinhold</a> 30 31 \version 0.0.0 32 */ 33 class OffsetFile : public BPositionIO { 34 public: 35 OffsetFile(); 36 OffsetFile(BFile *file, off_t offset); 37 virtual ~OffsetFile(); 38 39 status_t SetTo(BFile *file, off_t offset); 40 void Unset(); 41 status_t InitCheck() const; 42 43 BFile *File() const; 44 45 ssize_t ReadAt(off_t pos, void *buffer, size_t size); 46 ssize_t WriteAt(off_t pos, const void *buffer, 47 size_t size); 48 off_t Seek(off_t position, uint32 seekMode); 49 off_t Position() const; 50 51 status_t SetSize(off_t size); 52 status_t GetSize(off_t *size) const; 53 54 off_t Offset() const; 55 56 private: 57 BFile* fFile; 58 off_t fOffset; 59 off_t fCurrentPosition; 60 }; 61 62 }; // namespace Storage 63 }; // namespace BPrivate 64 65 #endif // _OFFSET_FILE_H 66 67 68