DD::Image::ImageCacheReadI Class Reference

Holder of temporary data to read files from cache: More...

Inherited by DD::Image::FileStreamRead, ImageCacheRead, and ImageCacheWriteRead.

Public Member Functions
virtual size_t	read (void *to, size_t n)=0
bool	tryRead (void *t, size_t n)
virtual void	seek (size_t to)=0
virtual void	seekRelative (off_t offset)=0
virtual void	close ()=0
virtual int	uniqueID () const =0

Detailed Description

Holder of temporary data to read files from cache:

Member Function Documentation

virtual size_t DD::Image::ImageCacheReadI::read ( void *  to, size_t  n  )

pure virtual

Read a block of data from a file opened with Image_Cache::open(). Returns number of bytes read.

Referenced by DD::Image::ViewerCache::read_from_cache().

bool DD::Image::ImageCacheReadI::tryRead ( void *  t, size_t  n  )

inline

Try to read a certain number of bytes. If it fails to read that number, return false.

virtual void DD::Image::ImageCacheReadI::seek ( size_t  to )

pure virtual

Move the file pointer to an absolute position in the file.

virtual void DD::Image::ImageCacheReadI::seekRelative ( off_t  offset )

pure virtual

Move the file pointer by n bytes.

Referenced by DD::Image::ViewerCache::read_from_cache().

virtual void DD::Image::ImageCacheReadI::close ( )

pure virtual

Close the file and delete the r data structure.

Referenced by DD::Image::ViewerCache::BoxPresent(), and DD::Image::ViewerCache::read_from_cache().

virtual int DD::Image::ImageCacheReadI::uniqueID ( ) const

pure virtual

get a unique ID for the memory-cached data, or 0 if the data was not in the memory cache. if the contents of the memory-cached data change (or if the data is removed from the memory cache and then reloaded) this number will increase.

Referenced by DD::Image::ViewerCache::BoxPresent().