zipios::BackBuffer - A BackBuffer instance is useful for reading the last part of a file in an efficient
Contents
Constructor & Destructor Documentation
zipios::BackBuffer::BackBuffer(istream&is,VirtualSeekervs=VirtualSeeker(),intchunk_size=1024)[inline],[explicit]BackBuffer constructor.
Parametersis 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.
ExceptionsFCollExceptionThrowniftheVirtualSeekervsthathasbeenspecifiedisinvalidfortheistreamis.
Definition at line 61 of file backbuffer.h.
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.
Member Function Documentation
intzipios::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.
Parametersread_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.
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 vector< unsigned char >.
PublicMemberFunctionsBackBuffer (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.
