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src/boost/lexical_cast.hpp  view on Meta::CPAN

                                 * Digit grouping is checked. That is, the positions of discarded
                                 * separators is examined for consistency with
                                 * use_facet<numpunct<charT> >(loc ).grouping()
                                 *
                                 * BUT what if there is no separators at all and grouping()
                                 * is not empty? Well, we have no extraced separators, so we
                                 * won`t check them for consistency. This will allow us to
                                 * work with "C" locale from other locales
                                 */
                                shall_we_return = false;
                                break;
                            } else {
                                if ( begin == end ) return false;
                                if (current_grouping < grouping_size-1 ) ++current_grouping;
                                remained = grouping[current_grouping];
                            }
                        }
                    }

                    if (shall_we_return) return true;
                }
            }
#endif
            {
                while ( begin <= end )
                {
                    T const multiplier_10 = multiplier * 10;
                    if (multiplier_10 / 10 != multiplier) multiplier_overflowed = true;

                    T const dig_value = *end - czero;
                    T const new_sub_value = multiplier_10 * dig_value;

                    if (*end < czero || *end >= czero + 10
                            /* detecting overflow */
                            || (dig_value && new_sub_value / dig_value != multiplier_10)
                            || static_cast<T>((std::numeric_limits<T>::max)()-new_sub_value) < value
                            || (multiplier_overflowed && dig_value)
                            )
                        return false;

                    value += new_sub_value;
                    multiplier *= 10;
                    --end;
                }
            }
            return true;
        }
    }

    namespace detail
    {
        template <class CharT>
        bool lc_iequal(const CharT* val, const CharT* lcase, const CharT* ucase, unsigned int len) BOOST_NOEXCEPT {
            for( unsigned int i=0; i < len; ++i ) {
                if ( val[i] != lcase[i] && val[i] != ucase[i] ) return false;
            }

            return true;
        }

        /* Returns true and sets the correct value if found NaN or Inf. */
        template <class CharT, class T>
        inline bool parse_inf_nan_impl(const CharT* begin, const CharT* end, T& value
            , const CharT* lc_NAN, const CharT* lc_nan
            , const CharT* lc_INFINITY, const CharT* lc_infinity
            , const CharT opening_brace, const CharT closing_brace) BOOST_NOEXCEPT
        {
            using namespace std;
            if (begin == end) return false;
            const CharT minus = lcast_char_constants<CharT>::minus;
            const CharT plus = lcast_char_constants<CharT>::plus;
            const int inifinity_size = 8;

            bool has_minus = false;
            /* Parsing +/- */
            if( *begin == minus)
            {
                ++ begin;
                has_minus = true;
            }
            else if( *begin == plus ) ++begin;

            if( end-begin < 3 ) return false;
            if( lc_iequal(begin, lc_nan, lc_NAN, 3) )
            {
                begin += 3;
                if (end != begin) /* It is 'nan(...)' or some bad input*/
                {
                    if(end-begin<2) return false; // bad input
                    -- end;
                    if( *begin != opening_brace || *end != closing_brace) return false; // bad input
                }

                if( !has_minus ) value = std::numeric_limits<T>::quiet_NaN();
                else value = (boost::math::changesign) (std::numeric_limits<T>::quiet_NaN());
                return true;
            } else
            if (( /* 'INF' or 'inf' */
                  end-begin==3
                  &&
                  lc_iequal(begin, lc_infinity, lc_INFINITY, 3)
                )
                ||
                ( /* 'INFINITY' or 'infinity' */
                  end-begin==inifinity_size
                  &&
                  lc_iequal(begin, lc_infinity, lc_INFINITY, inifinity_size)
                )
             )
            {
                if( !has_minus ) value = std::numeric_limits<T>::infinity();
                else value = (boost::math::changesign) (std::numeric_limits<T>::infinity());
                return true;
            }

            return false;
        }

        template <class CharT, class T>
        bool put_inf_nan_impl(CharT* begin, CharT*& end, const T& value
                         , const CharT* lc_nan
                         , const CharT* lc_infinity) BOOST_NOEXCEPT
        {
            using namespace std;
            const CharT minus = lcast_char_constants<CharT>::minus;
            if ( (boost::math::isnan)(value) )
            {
                if ( (boost::math::signbit)(value) )
                {
                    *begin = minus;
                    ++ begin;
                }

                memcpy(begin, lc_nan, 3 * sizeof(CharT));
                end = begin + 3;
                return true;
            } else if ( (boost::math::isinf)(value) )
            {
                if ( (boost::math::signbit)(value) )
                {
                    *begin = minus;
                    ++ begin;
                }

                memcpy(begin, lc_infinity, 3 * sizeof(CharT));
                end = begin + 3;
                return true;
            }

            return false;
        }


#ifndef BOOST_LCAST_NO_WCHAR_T
        template <class T>