zipios::BackBuffer(3)
NAME
zipios::BackBuffer - A BackBuffer instance is useful for reading the
last part of a file in an efficient manner, when it is not known
exactly how far back (towards the front!) to go, to find the start of
the desired data block.
SYNOPSIS
#include <backbuffer.h> Inherits std::vector< unsigned char >. Public Member Functions BackBuffer (istream &is, VirtualSeeker vs=VirtualSeeker(), int chunk_size=1024) BackBuffer constructor. int readChunk (int &read_pointer) Reads another chunk and returns the size of the chunk that has been read.
Detailed Description
A BackBuffer instance is useful for reading the last part of a file in
an efficient manner, when it is not known exactly how far back (towards
the front!) to go, to find the start of the desired data block.
BackBuffer is a vector< unsigned char > that fills itself with data
from a file by reading chunks from the end of the file progressing
towards the start. Upon construction the BackBuffer instance is
associated with a file and a chunksize can be specified. To read a
chunk of the file into the BackBuffer call readChunk().
Definition at line 32 of file backbuffer.h.
Constructor & Destructor Documentation
- zipios::BackBuffer::BackBuffer (istream & is, VirtualSeeker vs =
- VirtualSeeker(), int chunk_size = 1024) [inline, explicit] BackBuffer constructor.
- Parameters:
is The istream to read the data from. The stream must be seekable, as BackBuffer will reposition the file position to read chunks from the back of the file.
chunk_size specifies the size of the chunks to read the file into the BackBuffer in. - Exceptions:
FCollException Thrown if the VirtualSeeker vs that has been specified is invalid for the istream is.
- Definition at line 61 of file backbuffer.h.
Member Function Documentation
- int zipios::BackBuffer::readChunk (int & read_pointer) [inline]
- Reads another chunk and returns the size of the chunk that has been
read. - Returns 0 on I/O failure.
- Parameters:
read_pointer When a new chunk is read in the already stored bytes change position in the BackBuffer. read_pointer is assumed by readChunk() to be a pointer into a position in the BackBuffer, and is updated to point to the same position in the file as it pointed to before the new chunk was read.
- Definition at line 75 of file backbuffer.h.
Author
- Generated automatically by Doxygen for Zipios++ from the source code.