// ----------------------------------------------------------------------------

// internals.hpp :  internal structs : stream_format_state, format_item. 

//                  included by format.hpp

// ----------------------------------------------------------------------------

//  Copyright Samuel Krempp 2003. Use, modification, and distribution are

//  subject to 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)

//  See http://www.boost.org/libs/format for library home page

// ----------------------------------------------------------------------------

#ifndef BOOST_FORMAT_INTERNALS_HPP

#define BOOST_FORMAT_INTERNALS_HPP

#include <string>

#include <boost/assert.hpp>

#include <boost/optional.hpp>

#include <boost/limits.hpp>

#include <boost/format/detail/compat_workarounds.hpp>

#include <boost/format/alt_sstream.hpp> // used as a dummy stream

namespace boost {

namespace io {

namespace detail {

//---- stream_format_state --------------------------------------------------//

//   set of params that define the format state of a stream

    template<class Ch, class Tr> 

    struct stream_format_state 

    {

        typedef BOOST_IO_STD basic_ios<Ch, Tr>   basic_ios;

        stream_format_state(Ch fill)                 { reset(fill); }

//        stream_format_state(const basic_ios& os)     { set_by_stream(os); }

        void reset(Ch fill);                     //- sets to default state.

        void set_by_stream(const basic_ios& os); //- sets to os's state.

        void apply_on(basic_ios & os,            //- applies format_state to the stream

                      boost::io::detail::locale_t * loc_default = 0) const;

        template<class T> 

        void apply_manip(T manipulator)          //- modifies state by applying manipulator

            { apply_manip_body<Ch, Tr, T>( *this, manipulator) ; }

        // --- data ---

        std::streamsize width_;

        std::streamsize precision_;

        Ch fill_; 

        std::ios_base::fmtflags flags_;

        std::ios_base::iostate  rdstate_;

        std::ios_base::iostate  exceptions_;

        boost::optional<boost::io::detail::locale_t>  loc_;

    };  

//---- format_item  ---------------------------------------------------------//

//   stores all parameters that can be specified in format strings

    template<class Ch, class Tr, class Alloc>  

    struct format_item 

    {     

        enum pad_values { zeropad = 1, spacepad =2, centered=4, tabulation = 8 };

                         // 1. if zeropad is set, all other bits are not, 

                         // 2. if tabulation is set, all others are not.

                         // centered and spacepad can be mixed freely.

        enum arg_values { argN_no_posit   = -1, // non-positional directive. will set argN later

                          argN_tabulation = -2, // tabulation directive. (no argument read) 

                          argN_ignored    = -3  // ignored directive. (no argument read)

        };

        typedef BOOST_IO_STD basic_ios<Ch, Tr>                    basic_ios;

        typedef detail::stream_format_state<Ch, Tr>               stream_format_state;

        typedef ::std::basic_string<Ch, Tr, Alloc>                string_type;

        format_item(Ch fill) :argN_(argN_no_posit), fmtstate_(fill), 

                              truncate_(max_streamsize()), pad_scheme_(0)  {}

        void reset(Ch fill);

        void compute_states(); // sets states  according to truncate and pad_scheme.

        static std::streamsize max_streamsize() { 

            return (std::numeric_limits<std::streamsize>::max)();

        }

        // --- data ---

        int         argN_;  //- argument number (starts at 0,  eg : %1 => argN=0)

                            //  negative values for items that don't process an argument

        string_type  res_;      //- result of the formatting of this item

        string_type  appendix_; //- piece of string between this item and the next

        stream_format_state fmtstate_;// set by parsing, is only affected by modify_item

        std::streamsize truncate_;//- is set for directives like %.5s that ask truncation

        unsigned int pad_scheme_;//- several possible padding schemes can mix. see pad_values

    }; 

//--- Definitions  ------------------------------------------------------------

// -   stream_format_state:: -------------------------------------------------

    template<class Ch, class Tr>

    void stream_format_state<Ch,Tr>:: apply_on (basic_ios & os,

                      boost::io::detail::locale_t * loc_default) const {

        // set the state of this stream according to our params

        if(width_ != -1)

            os.width(width_);

        if(precision_ != -1)

            os.precision(precision_);

        if(fill_ != 0)

            os.fill(fill_);

        os.flags(flags_);

        os.clear(rdstate_);

        os.exceptions(exceptions_);

#if !defined(BOOST_NO_STD_LOCALE)

        if(loc_)

            os.imbue(loc_.get());

        else if(loc_default)

            os.imbue(*loc_default);

#endif        

    }

    template<class Ch, class Tr>

    void stream_format_state<Ch,Tr>:: set_by_stream(const basic_ios& os) {

        // set our params according to the state of this stream

        flags_ = os.flags();

        width_ = os.width();

        precision_ = os.precision();

        fill_ = os.fill();

        rdstate_ = os.rdstate();

        exceptions_ = os.exceptions();

    }

    template<class Ch, class Tr, class T>

    void apply_manip_body( stream_format_state<Ch, Tr>& self,

                           T manipulator) {

        // modify our params according to the manipulator

        basic_oaltstringstream<Ch, Tr>  ss;

        self.apply_on( ss );

        ss << manipulator;

        self.set_by_stream( ss );

    }

    template<class Ch, class Tr> inline

    void stream_format_state<Ch,Tr>:: reset(Ch fill) {

        // set our params to standard's default state.   cf § 27.4.4.1 of the C++ norm

        width_=0; precision_=6; 

        fill_=fill; // default is widen(' '), but we cant compute it without the locale

        flags_ = std::ios_base::dec | std::ios_base::skipws; 

        // the adjust_field part is left equal to 0, which means right.

        exceptions_ = std::ios_base::goodbit;

        rdstate_ = std::ios_base::goodbit;

    }

// ---   format_item:: --------------------------------------------------------

    template<class Ch, class Tr, class Alloc> 

    void format_item<Ch, Tr, Alloc>:: 

    reset (Ch fill) { 

        argN_=argN_no_posit; truncate_ = max_streamsize(); pad_scheme_ =0; 

        res_.resize(0); appendix_.resize(0);

        fmtstate_.reset(fill);

    }

    template<class Ch, class Tr, class Alloc> 

    void format_item<Ch, Tr, Alloc>:: 

    compute_states() {

        // reflect pad_scheme_   on  fmt_state_

        //   because some pad_schemes has complex consequences on several state params.

        if(pad_scheme_ & zeropad) {

            // ignore zeropad in left alignment :

            if(fmtstate_.flags_ & std::ios_base::left) {

              BOOST_ASSERT(!(fmtstate_.flags_ &(std::ios_base::adjustfield ^std::ios_base::left)));

              // only left bit might be set. (not right, nor internal)

              pad_scheme_ = pad_scheme_ & (~zeropad); 

            }

            else { 

                pad_scheme_ &= ~spacepad; // printf ignores spacepad when zeropadding

                fmtstate_.fill_='0'; 

                fmtstate_.flags_ = (fmtstate_.flags_ & ~std::ios_base::adjustfield) 

                    | std::ios_base::internal;

                // removes all adjustfield bits, and adds internal.

            }

        }

        if(pad_scheme_ & spacepad) {

            if(fmtstate_.flags_ & std::ios_base::showpos)

                pad_scheme_ &= ~spacepad;

        }

    }

} } } // namespaces boost :: io :: detail

#endif // BOOST_FORMAT_INTERNALS_HPP