FBB::ImmapStream - Input Stream using mmap(2) through FBB::MmapBuf

       Frank B. Brokken (f.b.brokken@rug.nl).

libbobcat-dev_6.07.01                               2005-2025                          FBB::ImmapStream(3bobcat)

       Bobcat is an acronym of `Brokken’s Own Base Classes And Templates’.

       o      https://fbb-git.gitlab.io/bobcat/: gitlab project page;

       Debian Bobcat project files:

       o      libbobcat6: debian package containing the shared library, changelog and copyright note;

       o      libbobcat-dev: debian package containing the static library, headers, manual pages, and  developer
              info;

       None Reported.

       o      ImmapStream():
              The default constructor merely constructs an empty ImmapStream object. To change it  to  a  usable
              object use move assignment;

       o      IOmmapStream(std::stringconst&fname,charconst*bufSize=0):
              The constructor initializes the ImmapStream object for a file named fname.

       By default bfImmapStream) uses a mapping buffer size of 10 times the standard page size, (cf. sysconf(3),
       and  the  member  pageSize below). The size of the mapping buffer can also be specified using the bufSize
       parameter. To specify it use a value followed by K,M, or G, representing, resp. 1024, 1024 *  1024,  and
       1024  *  1024  *  1024  bytes.  The final buffer size is at least equal to the standard page size. When a
       larger value is specified the used buffer size is set to specified/pageSize*pageSize.  )

       The move constructor and move assignment operator are available.
       The copy constructor and copy assignment operator are not available.

       This is free software, distributed under the terms of the GNU General Public License (GPL).

FBB::ImmapStream  objects  are  used  to  extract  information from files which are made available in the
       virtual address space of the calling process. Using the virtual address space is handled by  the  class’s
       privately inherited FBB::MmapBuf (std::streambuf class.

       By  mapping  files  in the process’s virtual address space the time required for processing such files is
       usually dramatically reduced.

       An std::exception is thrown, and an error message is written to  cerr  if  the  FBB::MmapBuf  base  class
       cannot determine the size of the specified file, or when the (un)mapping cannot be performed.

       An example is provided in bobcat’s source archive and gitlab repository at bobcat/immapstream/demo.

bobcat/immapstream - defines the class interface

std::istream, privately from FBB::MmapBuf.

       All members of std::istream are available, as FBB::ImmapStream inherits from that class.

       o      size_tbufSize()const:
              returns the used t(mmap) buffer size;

       o      size_tfileSize()const:
              returns the size of the specified file.

       o      size_tpageSize()const:
              returns the smallest page size used by t(mmap).

       FBB::ImmapStream - Input Stream using mmap(2) through FBB::MmapBuf

FBB
       All  constructors,  members,  operators  and manipulators, mentioned in this man-page, are defined in the
       namespace FBB.

bobcat(7), iommapstream(3bobcat), ommapstream(3bobcat), mmap(2), mmapbuf(3bobcat) sysconf(3)

#include<bobcat/immapstream>

       Linking option: -lbobcat