view release on metacpan or  search on metacpan

src/boost/format/parsing.hpp  view on Meta::CPAN

    // -end parse_printf_directive()

    template<class String, class Facet>
    int upper_bound_from_fstring(const String& buf, 
                                 const typename String::value_type arg_mark,
                                 const Facet& fac, 
                                 unsigned char exceptions) 
    {
        // quick-parsing of the format-string to count arguments mark (arg_mark, '%')
        // returns : upper bound on the number of format items in the format strings
        using namespace boost::io;
        typename String::size_type i1=0;
        int num_items=0;
        while( (i1=buf.find(arg_mark,i1)) != String::npos ) {
            if( i1+1 >= buf.size() ) {
                if(exceptions & bad_format_string_bit)
                    boost::throw_exception(bad_format_string(i1, buf.size() )); // must not end in ".. %"
                else {
                  ++num_items;
                  break;
                }
            }
            if(buf[i1+1] == buf[i1] ) {// escaped "%%"
                i1+=2; continue; 
            }

            ++i1;
            // in case of %N% directives, dont count it double (wastes allocations..) :
            i1 = detail::wrap_scan_notdigit(fac, buf.begin()+i1, buf.end()) - buf.begin();
            if( i1 < buf.size() && buf[i1] == arg_mark )
                ++i1;
            ++num_items;
        }
        return num_items;
    }
    template<class String> inline
    void append_string(String& dst, const String& src, 
                       const typename String::size_type beg, 
                       const typename String::size_type end) {
#if !defined(BOOST_NO_STRING_APPEND)
        dst.append(src.begin()+beg, src.begin()+end);
#else
        dst += src.substr(beg, end-beg);
#endif
    }

} // detail namespace
} // io namespace



// -----------------------------------------------
//  format :: parse(..)

    template<class Ch, class Tr, class Alloc>
    basic_format<Ch, Tr, Alloc>& basic_format<Ch, Tr, Alloc>:: 
    parse (const string_type& buf) {
        // parse the format-string 
        using namespace std;
#if !defined(BOOST_NO_STD_LOCALE)
        const std::ctype<Ch> & fac = BOOST_USE_FACET( std::ctype<Ch>, getloc());
#else
        io::basic_oaltstringstream<Ch, Tr, Alloc> fac; 
        //has widen and narrow even on compilers without locale
#endif

        const Ch arg_mark = io::detail::const_or_not(fac).widen( '%');
        bool ordered_args=true; 
        int max_argN=-1;

        // A: find upper_bound on num_items and allocates arrays
        int num_items = io::detail::upper_bound_from_fstring(buf, arg_mark, fac, exceptions());
        make_or_reuse_data(num_items);

        // B: Now the real parsing of the format string :
        num_items=0;
        typename string_type::size_type i0=0, i1=0;
        typename string_type::const_iterator it;
        bool special_things=false;
        int cur_item=0;
        while( (i1=buf.find(arg_mark,i1)) != string_type::npos ) {
            string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_;
            if( buf[i1+1] == buf[i1] ) { // escaped mark, '%%' 
                io::detail::append_string(piece, buf, i0, i1+1);
                i1+=2; i0=i1;
                continue; 
            }
            BOOST_ASSERT(  static_cast<unsigned int>(cur_item) < items_.size() || cur_item==0);

            if(i1!=i0) {
                io::detail::append_string(piece, buf, i0, i1);
                i0=i1;
            }
            ++i1;
            it = buf.begin()+i1;
            bool parse_ok = io::detail::parse_printf_directive(
                it, buf.end(), &items_[cur_item], fac, i1, exceptions());
            i1 = it - buf.begin();
            if( ! parse_ok ) // the directive will be printed verbatim
                continue; 
            i0=i1;
            items_[cur_item].compute_states(); // process complex options, like zeropad, into params

            int argN=items_[cur_item].argN_;
            if(argN == format_item_t::argN_ignored)
                continue;
            if(argN ==format_item_t::argN_no_posit)
                ordered_args=false;
            else if(argN == format_item_t::argN_tabulation) special_things=true;
            else if(argN > max_argN) max_argN = argN;
            ++num_items;
            ++cur_item;
        } // loop on %'s
        BOOST_ASSERT(cur_item == num_items);
    
        // store the final piece of string
        {
            string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_;
            io::detail::append_string(piece, buf, i0, buf.size());
        }