Chris@102: // Copyright Kevlin Henney, 2000-2005.
Chris@102: // Copyright Alexander Nasonov, 2006-2010.
Chris@102: // Copyright Antony Polukhin, 2011-2014.
Chris@102: //
Chris@102: // Distributed under the Boost Software License, Version 1.0. (See
Chris@102: // accompanying file LICENSE_1_0.txt or copy at
Chris@102: // http://www.boost.org/LICENSE_1_0.txt)
Chris@102: //
Chris@102: // what:  lexical_cast custom keyword cast
Chris@102: // who:   contributed by Kevlin Henney,
Chris@102: //        enhanced with contributions from Terje Slettebo,
Chris@102: //        with additional fixes and suggestions from Gennaro Prota,
Chris@102: //        Beman Dawes, Dave Abrahams, Daryle Walker, Peter Dimov,
Chris@102: //        Alexander Nasonov, Antony Polukhin, Justin Viiret, Michael Hofmann,
Chris@102: //        Cheng Yang, Matthew Bradbury, David W. Birdsall, Pavel Korzh and other Boosters
Chris@102: // when:  November 2000, March 2003, June 2005, June 2006, March 2011 - 2014
Chris@102: 
Chris@102: #ifndef BOOST_LEXICAL_CAST_DETAIL_LCAST_UNSIGNED_CONVERTERS_HPP
Chris@102: #define BOOST_LEXICAL_CAST_DETAIL_LCAST_UNSIGNED_CONVERTERS_HPP
Chris@102: 
Chris@102: #include <boost/config.hpp>
Chris@102: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@102: #   pragma once
Chris@102: #endif
Chris@102: 
Chris@102: #include <climits>
Chris@102: #include <cstddef>
Chris@102: #include <string>
Chris@102: #include <cstring>
Chris@102: #include <cstdio>
Chris@102: #include <boost/limits.hpp>
Chris@102: #include <boost/mpl/if.hpp>
Chris@102: #include <boost/type_traits/ice.hpp>
Chris@102: #include <boost/static_assert.hpp>
Chris@102: #include <boost/detail/workaround.hpp>
Chris@102: 
Chris@102: 
Chris@102: #ifndef BOOST_NO_STD_LOCALE
Chris@102: #   include <locale>
Chris@102: #else
Chris@102: #   ifndef BOOST_LEXICAL_CAST_ASSUME_C_LOCALE
Chris@102:         // Getting error at this point means, that your STL library is old/lame/misconfigured.
Chris@102:         // If nothing can be done with STL library, define BOOST_LEXICAL_CAST_ASSUME_C_LOCALE,
Chris@102:         // but beware: lexical_cast will understand only 'C' locale delimeters and thousands
Chris@102:         // separators.
Chris@102: #       error "Unable to use <locale> header. Define BOOST_LEXICAL_CAST_ASSUME_C_LOCALE to force "
Chris@102: #       error "boost::lexical_cast to use only 'C' locale during conversions."
Chris@102: #   endif
Chris@102: #endif
Chris@102: 
Chris@102: #include <boost/lexical_cast/detail/lcast_char_constants.hpp>
Chris@102: #include <boost/type_traits/make_unsigned.hpp>
Chris@102: #include <boost/type_traits/is_signed.hpp>
Chris@102: #include <boost/noncopyable.hpp>
Chris@102: 
Chris@102: namespace boost 
Chris@102: {
Chris@102:     namespace detail // lcast_to_unsigned
Chris@102:     {
Chris@102:         template<class T>
Chris@102:         inline
Chris@102:         BOOST_DEDUCED_TYPENAME boost::make_unsigned<T>::type lcast_to_unsigned(const T value) BOOST_NOEXCEPT {
Chris@102:             typedef BOOST_DEDUCED_TYPENAME boost::make_unsigned<T>::type result_type;
Chris@102:             return value < 0 
Chris@102:                 ? static_cast<result_type>(0u - static_cast<result_type>(value)) 
Chris@102:                 : static_cast<result_type>(value);
Chris@102:         }
Chris@102:     }
Chris@102: 
Chris@102:     namespace detail // lcast_put_unsigned
Chris@102:     {
Chris@102:         template <class Traits, class T, class CharT>
Chris@102:         class lcast_put_unsigned: boost::noncopyable {
Chris@102:             typedef BOOST_DEDUCED_TYPENAME Traits::int_type int_type;
Chris@102:             BOOST_DEDUCED_TYPENAME boost::mpl::if_c<
Chris@102:                     (sizeof(int_type) > sizeof(T))
Chris@102:                     , int_type
Chris@102:                     , T
Chris@102:             >::type         m_value;
Chris@102:             CharT*          m_finish;
Chris@102:             CharT    const  m_czero;
Chris@102:             int_type const  m_zero;
Chris@102: 
Chris@102:         public:
Chris@102:             lcast_put_unsigned(const T n_param, CharT* finish) BOOST_NOEXCEPT 
Chris@102:                 : m_value(n_param), m_finish(finish)
Chris@102:                 , m_czero(lcast_char_constants<CharT>::zero), m_zero(Traits::to_int_type(m_czero))
Chris@102:             {
Chris@102: #ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
Chris@102:                 BOOST_STATIC_ASSERT(!std::numeric_limits<T>::is_signed);
Chris@102: #endif
Chris@102:             }
Chris@102: 
Chris@102:             CharT* convert() {
Chris@102: #ifndef BOOST_LEXICAL_CAST_ASSUME_C_LOCALE
Chris@102:                 std::locale loc;
Chris@102:                 if (loc == std::locale::classic()) {
Chris@102:                     return main_convert_loop();
Chris@102:                 }
Chris@102: 
Chris@102:                 typedef std::numpunct<CharT> numpunct;
Chris@102:                 numpunct const& np = BOOST_USE_FACET(numpunct, loc);
Chris@102:                 std::string const grouping = np.grouping();
Chris@102:                 std::string::size_type const grouping_size = grouping.size();
Chris@102: 
Chris@102:                 if (!grouping_size || grouping[0] <= 0) {
Chris@102:                     return main_convert_loop();
Chris@102:                 }
Chris@102: 
Chris@102: #ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
Chris@102:                 // Check that ulimited group is unreachable:
Chris@102:                 BOOST_STATIC_ASSERT(std::numeric_limits<T>::digits10 < CHAR_MAX);
Chris@102: #endif
Chris@102:                 CharT const thousands_sep = np.thousands_sep();
Chris@102:                 std::string::size_type group = 0; // current group number
Chris@102:                 char last_grp_size = grouping[0];
Chris@102:                 char left = last_grp_size;
Chris@102: 
Chris@102:                 do {
Chris@102:                     if (left == 0) {
Chris@102:                         ++group;
Chris@102:                         if (group < grouping_size) {
Chris@102:                             char const grp_size = grouping[group];
Chris@102:                             last_grp_size = (grp_size <= 0 ? static_cast<char>(CHAR_MAX) : grp_size);
Chris@102:                         }
Chris@102: 
Chris@102:                         left = last_grp_size;
Chris@102:                         --m_finish;
Chris@102:                         Traits::assign(*m_finish, thousands_sep);
Chris@102:                     }
Chris@102: 
Chris@102:                     --left;
Chris@102:                 } while (main_convert_iteration());
Chris@102: 
Chris@102:                 return m_finish;
Chris@102: #else
Chris@102:                 return main_convert_loop();
Chris@102: #endif
Chris@102:             }
Chris@102: 
Chris@102:         private:
Chris@102:             inline bool main_convert_iteration() BOOST_NOEXCEPT {
Chris@102:                 --m_finish;
Chris@102:                 int_type const digit = static_cast<int_type>(m_value % 10U);
Chris@102:                 Traits::assign(*m_finish, Traits::to_char_type(m_zero + digit));
Chris@102:                 m_value /= 10;
Chris@102:                 return !!m_value; // suppressing warnings
Chris@102:             }
Chris@102: 
Chris@102:             inline CharT* main_convert_loop() BOOST_NOEXCEPT {
Chris@102:                 while (main_convert_iteration());
Chris@102:                 return m_finish;
Chris@102:             }
Chris@102:         };
Chris@102:     }
Chris@102: 
Chris@102:     namespace detail // lcast_ret_unsigned
Chris@102:     {
Chris@102:         template <class Traits, class T, class CharT>
Chris@102:         class lcast_ret_unsigned: boost::noncopyable {
Chris@102:             bool m_multiplier_overflowed;
Chris@102:             T m_multiplier;
Chris@102:             T& m_value;
Chris@102:             const CharT* const m_begin;
Chris@102:             const CharT* m_end;
Chris@102:     
Chris@102:         public:
Chris@102:             lcast_ret_unsigned(T& value, const CharT* const begin, const CharT* end) BOOST_NOEXCEPT
Chris@102:                 : m_multiplier_overflowed(false), m_multiplier(1), m_value(value), m_begin(begin), m_end(end)
Chris@102:             {
Chris@102: #ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
Chris@102:                 BOOST_STATIC_ASSERT(!std::numeric_limits<T>::is_signed);
Chris@102: 
Chris@102:                 // GCC when used with flag -std=c++0x may not have std::numeric_limits
Chris@102:                 // specializations for __int128 and unsigned __int128 types.
Chris@102:                 // Try compilation with -std=gnu++0x or -std=gnu++11.
Chris@102:                 //
Chris@102:                 // http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40856
Chris@102:                 BOOST_STATIC_ASSERT_MSG(std::numeric_limits<T>::is_specialized,
Chris@102:                     "std::numeric_limits are not specialized for integral type passed to boost::lexical_cast"
Chris@102:                 );
Chris@102: #endif
Chris@102:             }
Chris@102: 
Chris@102:             inline bool convert() {
Chris@102:                 CharT const czero = lcast_char_constants<CharT>::zero;
Chris@102:                 --m_end;
Chris@102:                 m_value = static_cast<T>(0);
Chris@102: 
Chris@102:                 if (m_begin > m_end || *m_end < czero || *m_end >= czero + 10)
Chris@102:                     return false;
Chris@102:                 m_value = static_cast<T>(*m_end - czero);
Chris@102:                 --m_end;
Chris@102: 
Chris@102: #ifdef BOOST_LEXICAL_CAST_ASSUME_C_LOCALE
Chris@102:                 return main_convert_loop();
Chris@102: #else
Chris@102:                 std::locale loc;
Chris@102:                 if (loc == std::locale::classic()) {
Chris@102:                     return main_convert_loop();
Chris@102:                 }
Chris@102: 
Chris@102:                 typedef std::numpunct<CharT> numpunct;
Chris@102:                 numpunct const& np = BOOST_USE_FACET(numpunct, loc);
Chris@102:                 std::string const& grouping = np.grouping();
Chris@102:                 std::string::size_type const grouping_size = grouping.size();
Chris@102: 
Chris@102:                 /* According to Programming languages - C++
Chris@102:                  * we MUST check for correct grouping
Chris@102:                  */
Chris@102:                 if (!grouping_size || grouping[0] <= 0) {
Chris@102:                     return main_convert_loop();
Chris@102:                 }
Chris@102: 
Chris@102:                 unsigned char current_grouping = 0;
Chris@102:                 CharT const thousands_sep = np.thousands_sep();
Chris@102:                 char remained = static_cast<char>(grouping[current_grouping] - 1);
Chris@102: 
Chris@102:                 for (;m_end >= m_begin; --m_end)
Chris@102:                 {
Chris@102:                     if (remained) {
Chris@102:                         if (!main_convert_iteration()) {
Chris@102:                             return false;
Chris@102:                         }
Chris@102:                         --remained;
Chris@102:                     } else {
Chris@102:                         if ( !Traits::eq(*m_end, thousands_sep) ) //|| begin == end ) return false;
Chris@102:                         {
Chris@102:                             /*
Chris@102:                              * According to Programming languages - C++
Chris@102:                              * Digit grouping is checked. That is, the positions of discarded
Chris@102:                              * separators is examined for consistency with
Chris@102:                              * use_facet<numpunct<charT> >(loc ).grouping()
Chris@102:                              *
Chris@102:                              * BUT what if there is no separators at all and grouping()
Chris@102:                              * is not empty? Well, we have no extraced separators, so we
Chris@102:                              * won`t check them for consistency. This will allow us to
Chris@102:                              * work with "C" locale from other locales
Chris@102:                              */
Chris@102:                             return main_convert_loop();
Chris@102:                         } else {
Chris@102:                             if (m_begin == m_end) return false;
Chris@102:                             if (current_grouping < grouping_size - 1) ++current_grouping;
Chris@102:                             remained = grouping[current_grouping];
Chris@102:                         }
Chris@102:                     }
Chris@102:                 } /*for*/
Chris@102: 
Chris@102:                 return true;
Chris@102: #endif
Chris@102:             }
Chris@102: 
Chris@102:         private:
Chris@102:             // Iteration that does not care about grouping/separators and assumes that all 
Chris@102:             // input characters are digits
Chris@102:             inline bool main_convert_iteration() BOOST_NOEXCEPT {
Chris@102:                 CharT const czero = lcast_char_constants<CharT>::zero;
Chris@102:                 T const maxv = (std::numeric_limits<T>::max)();
Chris@102: 
Chris@102:                 m_multiplier_overflowed = m_multiplier_overflowed || (maxv/10 < m_multiplier);
Chris@102:                 m_multiplier = static_cast<T>(m_multiplier * 10);
Chris@102: 
Chris@102:                 T const dig_value = static_cast<T>(*m_end - czero);
Chris@102:                 T const new_sub_value = static_cast<T>(m_multiplier * dig_value);
Chris@102: 
Chris@102:                 // We must correctly handle situations like `000000000000000000000000000001`.
Chris@102:                 // So we take care of overflow only if `dig_value` is not '0'.
Chris@102:                 if (*m_end < czero || *m_end >= czero + 10  // checking for correct digit
Chris@102:                     || (dig_value && (                      // checking for overflow of ... 
Chris@102:                         m_multiplier_overflowed                             // ... multiplier
Chris@102:                         || static_cast<T>(maxv / dig_value) < m_multiplier  // ... subvalue
Chris@102:                         || static_cast<T>(maxv - new_sub_value) < m_value   // ... whole expression
Chris@102:                     ))
Chris@102:                 ) return false;
Chris@102: 
Chris@102:                 m_value = static_cast<T>(m_value + new_sub_value);
Chris@102:                 
Chris@102:                 return true;
Chris@102:             }
Chris@102: 
Chris@102:             bool main_convert_loop() BOOST_NOEXCEPT {
Chris@102:                 for ( ; m_end >= m_begin; --m_end) {
Chris@102:                     if (!main_convert_iteration()) {
Chris@102:                         return false;
Chris@102:                     }
Chris@102:                 }
Chris@102:             
Chris@102:                 return true;
Chris@102:             }
Chris@102:         };
Chris@102:     }
Chris@102: } // namespace boost
Chris@102: 
Chris@102: #endif // BOOST_LEXICAL_CAST_DETAIL_LCAST_UNSIGNED_CONVERTERS_HPP
Chris@102: