Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for a snapshot of the develop branch, built from commit efe1a47bd1.

boost/io/ios_state.hpp

/*
Copyright 2002, 2005 Daryle Walker

Distributed under the Boost Software License, Version 1.0.
(http://www.boost.org/LICENSE_1_0.txt)
*/
#ifndef BOOST_IO_IOS_STATE_HPP
#define BOOST_IO_IOS_STATE_HPP

#include <boost/config.hpp>
#include <boost/io_fwd.hpp>
#include <ios>
#ifndef BOOST_NO_STD_LOCALE
#include <locale>
#endif
#include <ostream>
#include <streambuf>
#include <string>

namespace boost {
namespace io {

class ios_flags_saver {
public:
    typedef std::ios_base state_type;
    typedef std::ios_base::fmtflags aspect_type;

    explicit ios_flags_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.flags()) { }

    ios_flags_saver(state_type& s, aspect_type a)
        : s_save_(s)
        , a_save_(s.flags(a)) { }

    ~ios_flags_saver() {
        this->restore();
    }

    void restore() {
        s_save_.flags(a_save_);
    }

private:
    ios_flags_saver(const ios_flags_saver&);
    ios_flags_saver& operator=(const ios_flags_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};

class ios_precision_saver {
public:
    typedef std::ios_base state_type;
    typedef std::streamsize aspect_type;

    explicit ios_precision_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.precision()) { }

    ios_precision_saver(state_type& s, aspect_type a)
        : s_save_(s)
        , a_save_(s.precision(a)) { }

    ~ios_precision_saver() {
        this->restore();
    }

    void restore() {
        s_save_.precision(a_save_);
    }

private:
    ios_precision_saver(const ios_precision_saver&);
    ios_precision_saver& operator=(const ios_precision_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};

class ios_width_saver {
public:
    typedef std::ios_base state_type;
    typedef std::streamsize aspect_type;

    explicit ios_width_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.width()) { }

    ios_width_saver(state_type& s, aspect_type a)
        : s_save_(s)
        , a_save_(s.width(a)) { }

    ~ios_width_saver() {
        this->restore();
    }

    void restore() {
        s_save_.width(a_save_);
    }

private:
    ios_width_saver(const ios_width_saver&);
    ios_width_saver& operator=(const ios_width_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};

template<class Ch, class Tr>
class basic_ios_iostate_saver {
public:
    typedef std::basic_ios<Ch, Tr> state_type;
    typedef std::ios_base::iostate aspect_type;

    explicit basic_ios_iostate_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.rdstate()) { }

    basic_ios_iostate_saver(state_type& s, aspect_type a)
        : s_save_(s)
        , a_save_(s.rdstate()) {
            s.clear(a);
        }

    ~basic_ios_iostate_saver() {
        this->restore();
    }

    void restore() {
        s_save_.clear(a_save_);
    }

private:
    basic_ios_iostate_saver(const basic_ios_iostate_saver&);
    basic_ios_iostate_saver& operator=(const basic_ios_iostate_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};

template<class Ch, class Tr>
class basic_ios_exception_saver {
public:
    typedef std::basic_ios<Ch, Tr> state_type;
    typedef std::ios_base::iostate aspect_type;

    explicit basic_ios_exception_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.exceptions()) { }

    basic_ios_exception_saver(state_type& s, aspect_type a)
        : s_save_(s)
        , a_save_(s.exceptions()) {
        s.exceptions(a);
    }

    ~basic_ios_exception_saver() {
        this->restore();
    }

    void restore() {
        s_save_.exceptions(a_save_);
    }

private:
    basic_ios_exception_saver(const basic_ios_exception_saver&);
    basic_ios_exception_saver& operator=(const basic_ios_exception_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};

template<class Ch, class Tr>
class basic_ios_tie_saver {
public:
    typedef std::basic_ios<Ch, Tr> state_type;
    typedef std::basic_ostream<Ch, Tr>* aspect_type;

    explicit basic_ios_tie_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.tie()) { }

    basic_ios_tie_saver(state_type& s, aspect_type a)
        : s_save_(s)
        , a_save_(s.tie(a)) { }

    ~basic_ios_tie_saver() {
        this->restore();
    }

    void restore() {
        s_save_.tie(a_save_);
    }

private:
    basic_ios_tie_saver(const basic_ios_tie_saver&);
    basic_ios_tie_saver& operator=(const basic_ios_tie_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};

template<class Ch, class Tr>
class basic_ios_rdbuf_saver {
public:
    typedef std::basic_ios<Ch, Tr> state_type;
    typedef std::basic_streambuf<Ch, Tr>* aspect_type;

    explicit basic_ios_rdbuf_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.rdbuf()) { }

    basic_ios_rdbuf_saver(state_type& s, aspect_type a)
        : s_save_(s)
        , a_save_(s.rdbuf(a)) { }

    ~basic_ios_rdbuf_saver() {
        this->restore();
    }

    void restore() {
        s_save_.rdbuf(a_save_);
    }

private:
    basic_ios_rdbuf_saver(const basic_ios_rdbuf_saver&);
    basic_ios_rdbuf_saver& operator=(const basic_ios_rdbuf_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};

template<class Ch, class Tr>
class basic_ios_fill_saver {
public:
    typedef std::basic_ios<Ch, Tr> state_type;
    typedef typename state_type::char_type aspect_type;

    explicit basic_ios_fill_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.fill()) { }

    basic_ios_fill_saver(state_type& s, aspect_type a)
        : s_save_(s)
        , a_save_(s.fill(a)) { }

    ~basic_ios_fill_saver() {
        this->restore();
    }

    void restore() {
        s_save_.fill(a_save_);
    }

private:
    basic_ios_fill_saver(const basic_ios_fill_saver&);
    basic_ios_fill_saver& operator=(const basic_ios_fill_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};

#ifndef BOOST_NO_STD_LOCALE
template<class Ch, class Tr>
class basic_ios_locale_saver {
public:
    typedef std::basic_ios<Ch, Tr> state_type;
    typedef std::locale aspect_type;

    explicit basic_ios_locale_saver(state_type& s)
        : s_save_(s)
        , a_save_(s.getloc()) { }

    basic_ios_locale_saver(state_type& s, const aspect_type& a)
        : s_save_(s)
        , a_save_(s.imbue(a)) { }

    ~basic_ios_locale_saver() {
        this->restore();
    }

    void restore() {
        s_save_.imbue(a_save_);
    }

private:
    basic_ios_locale_saver(const basic_ios_locale_saver&);
    basic_ios_locale_saver& operator=(const basic_ios_locale_saver&);

    state_type& s_save_;
    aspect_type a_save_;
};
#endif

class ios_iword_saver {
public:
    typedef std::ios_base state_type;
    typedef int index_type;
    typedef long aspect_type;

    explicit ios_iword_saver(state_type& s, index_type i)
        : s_save_(s)
        , a_save_(s.iword(i))
        , i_save_(i) { }

    ios_iword_saver(state_type& s, index_type i, aspect_type a)
        : s_save_(s)
        , a_save_(s.iword(i))
        , i_save_(i) {
        s.iword(i) = a;
    }

    ~ios_iword_saver() {
        this->restore();
    }

    void restore() {
        s_save_.iword(i_save_) = a_save_;
    }

private:
    ios_iword_saver(const ios_iword_saver&);
    ios_iword_saver& operator=(const ios_iword_saver&);

    state_type& s_save_;
    aspect_type a_save_;
    index_type i_save_;
};

class ios_pword_saver {
public:
    typedef std::ios_base state_type;
    typedef int index_type;
    typedef void* aspect_type;

    explicit ios_pword_saver(state_type& s, index_type i)
        : s_save_(s)
        , a_save_(s.pword(i))
        , i_save_(i) { }

    ios_pword_saver(state_type& s, index_type i, aspect_type a)
        : s_save_(s)
        , a_save_(s.pword(i))
        , i_save_(i) {
        s.pword(i) = a;
    }

    ~ios_pword_saver() {
        this->restore();
    }

    void restore() {
        s_save_.pword(i_save_) = a_save_;
    }

private:
    ios_pword_saver(const ios_pword_saver&);
    ios_pword_saver operator=(const ios_pword_saver&);

    state_type& s_save_;
    aspect_type a_save_;
    index_type i_save_;
};

class ios_base_all_saver {
public:
    typedef std::ios_base state_type;

    explicit ios_base_all_saver(state_type& s)
        : s_save_(s)
        , a1_save_(s.flags())
        , a2_save_(s.precision())
        , a3_save_(s.width()) { }

    ~ios_base_all_saver() {
        this->restore();
    }

    void restore() {
        s_save_.width(a3_save_);
        s_save_.precision(a2_save_);
        s_save_.flags(a1_save_);
    }

private:
    ios_base_all_saver(const ios_base_all_saver&);
    ios_base_all_saver& operator=(const ios_base_all_saver&);

    state_type& s_save_;
    state_type::fmtflags a1_save_;
    std::streamsize a2_save_;
    std::streamsize a3_save_;
};

template<class Ch, class Tr>
class basic_ios_all_saver {
public:
    typedef std::basic_ios<Ch, Tr> state_type;

    explicit basic_ios_all_saver(state_type& s)
        : s_save_(s)
        , a1_save_(s.flags())
        , a2_save_(s.precision())
        , a3_save_(s.width())
        , a4_save_(s.rdstate())
        , a5_save_(s.exceptions())
        , a6_save_(s.tie())
        , a7_save_(s.rdbuf())
        , a8_save_(s.fill())
#ifndef BOOST_NO_STD_LOCALE
        , a9_save_(s.getloc())
#endif
        { }

    ~basic_ios_all_saver() {
        this->restore();
    }

    void restore() {
#ifndef BOOST_NO_STD_LOCALE
        s_save_.imbue(a9_save_);
#endif
        s_save_.fill(a8_save_);
        s_save_.rdbuf(a7_save_);
        s_save_.tie(a6_save_);
        s_save_.exceptions(a5_save_);
        s_save_.clear(a4_save_);
        s_save_.width(a3_save_);
        s_save_.precision(a2_save_);
        s_save_.flags(a1_save_);
    }

private:
    basic_ios_all_saver(const basic_ios_all_saver&);
    basic_ios_all_saver& operator=(const basic_ios_all_saver&);

    state_type& s_save_;
    typename state_type::fmtflags a1_save_;
    std::streamsize a2_save_;
    std::streamsize a3_save_;
    typename state_type::iostate a4_save_;
    typename state_type::iostate a5_save_;
    std::basic_ostream<Ch, Tr>* a6_save_;
    std::basic_streambuf<Ch, Tr>* a7_save_;
    typename state_type::char_type a8_save_;
#ifndef BOOST_NO_STD_LOCALE
    std::locale a9_save_;
#endif
};

class ios_all_word_saver {
public:
    typedef std::ios_base state_type;
    typedef int index_type;

    ios_all_word_saver(state_type& s, index_type i)
        : s_save_(s)
        , i_save_(i)
        , a1_save_(s.iword(i))
        , a2_save_(s.pword(i)) { }

    ~ios_all_word_saver() {
        this->restore();
    }

    void restore() {
        s_save_.pword(i_save_) = a2_save_;
        s_save_.iword(i_save_) = a1_save_;
    }

private:
    ios_all_word_saver(const ios_all_word_saver&);
    ios_all_word_saver& operator=(const ios_all_word_saver&);

    state_type& s_save_;
    index_type i_save_;
    long a1_save_;
    void* a2_save_;
};

} /* io */
} /* boost */

#endif