iobuf3bobcat

Usage

Overview

This class implements a specialization of the std::streambuf class, allowing input operations from and output operations to different files. It is intended to be used in combination with FBB::IOStream, thus allowing all stream-based input and output operations using the same object without the need to use seek-operations. Using an FBB::IOStream object it is, e.g., possible to construct two-way communications using pipes, much like the facilities offered by sockets.

If the streams that will be associated with the IOBuf object support seeking, then the IOBuf will do so to. Seeking might also be available for a single stream (either the std::istream or the std::ostream).

When the IOBuf object goes out of scope, its associated std::ostream object is flushed.

Namespace

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

Inherits from

std::streambuf

Constructors

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IOBuf():
The default constructor results in a IOBuf object that cannot be immediately used. Its member open() must be called first.

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IOBuf(std::istream &in, std::ostream &out):
This constructor associates the IOBuf object with a std::istream and a std::ostream. All output operations will be passed on to the std::ostream, all input operations to the std::istream. The streams passed to IOBuf() should outlive the IOBuf object.

Copy and move constructors (and assignment operators) are not available.

Member functions

All members of std::streambuf are available, as FBB::IOBuf inherits from these classes.

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void open(std::istream &in, std::ostream &out):
This member (re)associates the IOBuf object with a std::istream and a std::ostream. All output operations will be passed on to the std::ostream, all input operations to the std::istream. The streams passed to IOBuf() should outlive the IOBuf object. If this member is called for an IOBuf object already associated with an std::ostream object, the already associated std::ostream object is flushed before setting up the new association.

Virtual protected member functions

The following std::streambuf member functions should only be called when the FBB::Streambuf object is associated with std::istream and std::ostream objects (i.e., they should not be called between the construction of a default FBB:IOBuf object and a subsequent call of IOBuf::open()):

The members listed in this section implement the tasks of comparably named virtual function in the class’s private interface. This separates the redefinable interface from the user-interface. The class IOStreamBuf can, in accordance with Liskov’s Substitution Principle, be used as a std:streambuf; but it also offers facilities for classes deriving from IOStreamBuf. These facilities are listed here.

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pos_type pSeekoff(off_type offset, std::ios::seekdir way, std::ios::openmode mode = std::ios::in | std::ios::out):
With seekable streams, repositions the associated std::istream or std::ostream is repositioned to offset offset, relative to way.

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pos_type pSeekpos(off_type offset, std::ios::openmode mode = std::ios::in | std::ios::out):
With seekable streams, repositions the associated std::istream or std::ostream is repositioned to offset offset, relative to

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std::streamsize pXsputn(char const *buffer, std::streamsize n):
This member inserts n characters from buffer into the associated std::ostream stream.

Examples

See the example provided with process(3bobcat).

Files

bobcat/iobuf - defines the class interface

Bobcat project files

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

Debian Bobcat project files:

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

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

Bobcat

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