numeric_utils.hpp

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//  Copyright (c) 2001-2008 Hartmut Kaiser
// 
//  Distributed under 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)

#if !defined(BOOST_SPIRIT_KARMA_NUMERIC_UTILS_FEB_23_2007_0841PM)
#define BOOST_SPIRIT_KARMA_NUMERIC_UTILS_FEB_23_2007_0841PM

#if defined(_MSC_VER) && (_MSC_VER >= 1020)
#pragma once      // MS compatible compilers support #pragma once
#endif

#include <boost/config/no_tr1/cmath.hpp>
#include <limits>

#include <boost/type_traits/is_integral.hpp>
#include <boost/spirit/home/support/char_class.hpp>
#include <boost/spirit/home/support/iso8859_1.hpp>
#include <boost/spirit/home/support/ascii.hpp>
#include <boost/spirit/home/support/unused.hpp>
#include <boost/spirit/home/karma/detail/generate_to.hpp>
#include <boost/spirit/home/karma/detail/string_generate.hpp>
#include <boost/spirit/home/support/detail/math/fpclassify.hpp>
#include <boost/spirit/home/support/detail/math/signbit.hpp>

///////////////////////////////////////////////////////////////////////////////
//
//  The value BOOST_KARMA_NUMERICS_LOOP_UNROLL specifies, how to unroll the 
//  integer string generation loop (see below).
//
//      Set the value to some integer in between 0 (no unrolling) and the 
//      largest expected generated integer string length (complete unrolling). 
//      If not specified, this value defaults to 6.
//
///////////////////////////////////////////////////////////////////////////////
#if !defined(BOOST_KARMA_NUMERICS_LOOP_UNROLL)
#define BOOST_KARMA_NUMERICS_LOOP_UNROLL 6
#endif

#if BOOST_KARMA_NUMERICS_LOOP_UNROLL < 0 
#error "Please set the BOOST_KARMA_NUMERICS_LOOP_UNROLL to a positive value!"
#endif

namespace boost { namespace spirit { namespace karma { 

    namespace detail 
    {
        ///////////////////////////////////////////////////////////////////////
        //
        //  return the absolute value from a given number, avoiding over- and 
        //  underflow
        //
        ///////////////////////////////////////////////////////////////////////
        inline unsigned short absolute_value (short n)
        {
            return (n >= 0) ? n : (unsigned short)(-n);
        }
        
        inline unsigned int absolute_value (int n)
        {
            return (n >= 0) ? n : (unsigned int)(-n);
        }

        inline unsigned long absolute_value (long n)
        {
            return (n >= 0) ? n : (unsigned long)(-n);
        }

#ifdef BOOST_HAS_LONG_LONG
        inline boost::ulong_long_type absolute_value (boost::long_long_type n)
        {
            return (n >= 0) ? n : (boost::ulong_long_type)(-n);
        }
#endif
        
        inline float absolute_value (float n)
        {
            return boost::math::signbit(n) ? boost::math::changesign(n) : n;
        }
        
        inline double absolute_value (double n)
        {
            return boost::math::signbit(n) ? boost::math::changesign(n) : n;
        }
        
        inline long double absolute_value (long double n)
        {
            return boost::math::signbit(n) ? boost::math::changesign(n) : n;
        }
        
        template <typename T>
        inline T absolute_value (T n)
        {
            using namespace std;
            return fabs(n);
        }

        ///////////////////////////////////////////////////////////////////////
        inline bool is_negative(float n) 
        { 
            return boost::math::signbit(n); 
        }
        
        inline bool is_negative(double n) 
        { 
            return boost::math::signbit(n); 
        }
        
        inline bool is_negative(long double n) 
        { 
            return boost::math::signbit(n); 
        }
        
        template <typename T>
        inline bool is_negative(T n)
        {
            return (n < 0) ? true : false;
        }
        
        ///////////////////////////////////////////////////////////////////////
        inline bool is_zero(float n) 
        { 
            return boost::math::fpclassify(n) == FP_ZERO; 
        }
        
        inline bool is_zero(double n) 
        { 
            return boost::math::fpclassify(n) == FP_ZERO; 
        }
        
        inline bool is_zero(long double n) 
        { 
            return boost::math::fpclassify(n) == FP_ZERO; 
        }
        
        template <typename T>
        inline bool is_zero(T n)
        {
            return (n == 0) ? true : false;
        }
        
        ///////////////////////////////////////////////////////////////////////
        struct cast_to_long
        {
            static long call(float n, mpl::false_)
            {
                return static_cast<long>(std::floor(n));
            }
            
            static long call(double n, mpl::false_)
            {
                return static_cast<long>(std::floor(n));
            }
            
            static long call(long double n, mpl::false_)
            {
                return static_cast<long>(std::floor(n));
            }
            
            template <typename T>
            static long call(T n, mpl::false_)
            {
                // allow for ADL to find the correct overload for floor and 
                // lround
                using namespace std;
                return lround(floor(n));
            }

            template <typename T>
            static long call(T n, mpl::true_)
            {
                return static_cast<long>(n);
            }

            template <typename T>
            static long call(T n)
            {
                return call(n, mpl::bool_<is_integral<T>::value>());
            }
        };
        
        ///////////////////////////////////////////////////////////////////////
        struct round_to_long
        {
            static long call(float n, mpl::false_)
            {
                return static_cast<long>(std::floor(n + 0.5f));
            }
            
            static long call(double n, mpl::false_)
            {
                return static_cast<long>(std::floor(n + 0.5));
            }
            
            static long call(long double n, mpl::false_)
            {
                return static_cast<long>(std::floor(n + 0.5l));
            }
            
            template <typename T>
            static long call(T n, mpl::false_)
            {
                using namespace std;
                return lround(n);
            }

            template <typename T>
            static long call(T n, mpl::true_)
            {
                return static_cast<long>(n);
            }

            template <typename T>
            static long call(T n)
            {
                return call(n, mpl::bool_<is_integral<T>::value>());
            }
        };
        
        ///////////////////////////////////////////////////////////////////////
        //
        //  Traits class for radix specific number conversion
        //
        //      Convert a digit from binary representation to character 
        //      representation:
        //
        //          static int digit(unsigned n);
        //
        ///////////////////////////////////////////////////////////////////////
        template<unsigned Radix, typename Tag>
        struct radix_traits;

        // Binary
        template<typename Tag>
        struct radix_traits<2, Tag>
        {
            static int digit(unsigned n)
            {
                return n + '0';
            }
        };

        // Octal
        template<typename Tag>
        struct radix_traits<8, Tag>
        {
            static int digit(unsigned n)
            {
                return n + '0';
            }
        };

        // Decimal 
        template<typename Tag>
        struct radix_traits<10, Tag>
        {
            static int digit(unsigned n)
            {
                return n + '0';
            }
        };

        // Hexadecimal, lower case
        template<>
        struct radix_traits<16, unused_type>
        {
            static int digit(unsigned n)
            {
                if (n <= 9)
                    return n + '0';
                return n - 10 + 'a';
            }
        };

        // Hexadecimal, upper case
        template<typename Tag>
        struct radix_traits<16, Tag>
        {
            typedef typename Tag::char_set char_set;
            typedef typename Tag::char_class char_class_;

            static int digit(unsigned n)
            {
                if (n <= 9)
                    return n + '0';

                using spirit::char_class::convert;
                return convert<char_set>::to(char_class_(), n - 10 + 'a');
            }
        };

        ///////////////////////////////////////////////////////////////////////
        template <unsigned Radix>
        struct divide
        {
            template <typename T>
            static T call(T& n, mpl::true_)
            {
                return n / Radix;
            }
            
            template <typename T>
            static T call(T& n, mpl::false_)
            {
                // Allow ADL to find the correct overload for floor
                using namespace std; 
                return floor(n / Radix);
            }
            
            template <typename T>
            static T call(T& n)
            {
                return call(n, mpl::bool_<is_integral<T>::value>());
            }
        };
        
        ///////////////////////////////////////////////////////////////////////
        template <unsigned Radix>
        struct remainder