Class Template symmetric_filter

Description
Headers
Reference
Examples

Description

The class template symmetric_filter is tool for generating models of DualUseFilter from models of SymmetricFilter. It is useful for defining filters based on C language APIs.

The Iostreams library uses symmetric_filter to implement the Zlib and Bzip2 Filters.

Headers

<boost/iostreams/filter/symmetric.hpp>

Reference

Synopsis

namespace boost { namespace iostreams {

template< typename SymmetricFilter,
          typename Alloc = std::allocator<...> >
class symmetric_filter {
public:
    typedef typename char_type_of<SymmetricFilter>::type  char_type;
    typedef implementation-defined                        category;

    explicit symmetric_filter(int buffer_size);

    template<typename T0>
    symmetric_filter(int buffer_size, const T0& t0);

    template<typename T0, typename T1>
    symmetric_filter(int buffer_size, const T0& t0, const T1& t1);

    template<typename T0, ..., typename TN>
    symmetric_filter( int buffer_size, const T0& t0,
                      const T1& t1, ..., const TN& tN );

    ...
protected:
    SymmetricFilter& filter();
    std::basic_string<char_type, Alloc> unconsumed_input() const;
};

} } // End namespace boost::io

Template parameters

SymmetricFilter- A model of SymmetricFilter
Alloc- A standard library allocator type ([ISO], 20.1.5), used to allocate a character buffer

symmetric_filter::symmetric_filter

    explicit symmetric_filter(int buffer_size);

Constructs an instance of symmetric_filter based on a default-constructed instance of the template parameter SymmetricFilter and having an internal buffer of size buffer_size.

symmetric_filter::symmetric_filter

    template<typename T0>
    symmetric_filter(int buffer_size, const T0& t0);

    template<typename T0, typename T1>
    symmetric_filter(int buffer_size, const T0& t0, const T1& t1);

    template<typename T0, ..., typename TN>
    symmetric_filter( int buffer_size, const T0& t0,
                              const T1& t1, ..., const TN& tN );

Each member constructs an instance of symmetric_filter based on an instance of the template parameter SymmetricFilter constructed with the given sequence of arguments and having an internal buffer of size buffer_size.

symmetric_filter::filter

    SymmetricFilter& filter();

Returns a reference to the underlying instance of SymmetricFilter.

symmetric_filter::unconsumed_input

    std::basic_string<char_type, Alloc> unconsumed_input() const;

Returns any uncomsumed data remaining in the internal buffer as a standard string. Valid from the time the end of a stream is reached — that is, from the time SymmetricFilter::filter returns false — until filter is invoked to begin processing a new sequence of data.

Examples

For example uses of symmetric_filter, see the headers <boost/iostreams/filter/zlib.hpp> and <boost/iostreams/filter/bzip2.hpp> and the corresponding implementation files <libs/iostreams/src/zlib.cpp> and <libs/iostreams/src/bzip2.cpp>.

© Copyright 2008 CodeRage, LLC
© Copyright 2004-2007 Jonathan Turkanis

Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)