boost/spirit/home/support/detail/math/nonfinite_num_facets.hpp

#ifndef BOOST_SPIRIT_MATH_NONFINITE_NUM_FACETS_HPP
#define BOOST_SPIRIT_MATH_NONFINITE_NUM_FACETS_HPP

// Copyright (c) 2006 Johan Rade

// 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)

#include <cstring>
#include <ios>
#include <limits>
#include <locale>
#include <boost/spirit/home/support/detail/math/fpclassify.hpp>
#include <boost/spirit/home/support/detail/math/signbit.hpp>

#ifdef _MSC_VER
#   pragma warning(push)
#   pragma warning(disable : 4127 4511 4512 4706)
#endif

namespace boost {
namespace spirit {
namespace math {


// flags -----------------------------------------------------------------------

const int legacy = 0x1;
const int signed_zero = 0x2;
const int trap_infinity = 0x4;
const int trap_nan = 0x8;


// class nonfinite_num_put -----------------------------------------------------

template<
    class CharType, 
    class OutputIterator = std::ostreambuf_iterator<CharType> 
>
class nonfinite_num_put : public std::num_put<CharType, OutputIterator> {
public:
    explicit nonfinite_num_put(int flags = 0) : flags_(flags) {}

protected:
    virtual OutputIterator do_put(
        OutputIterator it, std::ios_base& iosb,
        CharType fill, double val) const
    {
        put_and_reset_width(it, iosb, fill, val);
        return it;
    }

    virtual OutputIterator do_put(
        OutputIterator it, std::ios_base& iosb,
        CharType fill, long double val) const
    {
        put_and_reset_width(it, iosb, fill, val);
        return it;
    }

private:
    template<class ValType> void put_and_reset_width(
        OutputIterator& it, std::ios_base& iosb,
        CharType fill, ValType val) const
    {
        put_impl(it, iosb, fill, val);
        iosb.width(0);
    }

    template<class ValType> void put_impl(
        OutputIterator& it, std::ios_base& iosb,
        CharType fill, ValType val) const
    {
        switch((boost::math::fpclassify)(val)) {

            case FP_INFINITE:
                if(flags_ & trap_infinity)
                    throw std::ios_base::failure("Infinity");
                else if((boost::math::signbit)(val))
                    put_num_and_fill(it, iosb, "-", "inf", fill);
                else if(iosb.flags() & std::ios_base::showpos)
                    put_num_and_fill(it, iosb, "+", "inf", fill);
                else
                    put_num_and_fill(it, iosb, "", "inf", fill);
                break;
            
            case FP_NAN:
                if(flags_ & trap_nan)
                    throw std::ios_base::failure("NaN");
                else if((boost::math::signbit)(val))
                    put_num_and_fill(it, iosb, "-", "nan", fill);
                else if(iosb.flags() & std::ios_base::showpos)
                    put_num_and_fill(it, iosb, "+", "nan", fill);
                else
                    put_num_and_fill(it, iosb, "", "nan", fill);
                break;

            case FP_ZERO:
                if(flags_ & signed_zero) {
                    if((boost::math::signbit)(val))
                        put_num_and_fill(it, iosb, "-", "0", fill);
                    else if(iosb.flags() & std::ios_base::showpos)
                        put_num_and_fill(it, iosb, "+", "0", fill);
                    else
                        put_num_and_fill(it, iosb, "", "0", fill);
                }
                else
                    put_num_and_fill(it, iosb, "", "0", fill);
                break;

            default:
                it = std::num_put<CharType, OutputIterator>::do_put(
                    it, iosb, fill, val);
                break;
        }
    }

    void put_num_and_fill(
        OutputIterator& it, std::ios_base& iosb, const char* prefix,
        const char* body, CharType fill) const
    {
        int width = (int)strlen(prefix) + (int)strlen(body);
        std::ios_base::fmtflags adjust
            = iosb.flags() & std::ios_base::adjustfield;
        const std::ctype<CharType>& ct
            = std::use_facet<std::ctype<CharType> >(iosb.getloc());

        if(adjust != std::ios_base::internal && adjust != std::ios_base::left)
            put_fill(it, iosb, fill, width);

        while(*prefix)
            *it = ct.widen(*(prefix++));

        if(adjust == std::ios_base::internal)
            put_fill(it, iosb, fill, width);

        if(iosb.flags() & std::ios_base::uppercase) {
            while(*body)
                *it = ct.toupper(ct.widen(*(body++)));
        }
        else {
            while(*body)
                *it = ct.widen(*(body++));
        }

        if(adjust == std::ios_base::left)
            put_fill(it, iosb, fill, width);
    }

    void put_fill(
        OutputIterator& it, std::ios_base& iosb, 
        CharType fill, int width) const
    {
        for(int i = iosb.width() - width; i > 0; --i)
            *it = fill;
    }

private:
    const int flags_;
};


// class nonfinite_num_get ------------------------------------------------------

template<
    class CharType, 
    class InputIterator = std::istreambuf_iterator<CharType> 
>
class nonfinite_num_get : public std::num_get<CharType, InputIterator> {
public:
    explicit nonfinite_num_get(int flags = 0) : flags_(flags) {}

protected:
    virtual InputIterator do_get(
        InputIterator it, InputIterator end, std::ios_base& iosb,
        std::ios_base::iostate& state, float& val) const
    {
        get_and_check_eof(it, end, iosb, state, val);
        return it;
    }

    virtual InputIterator do_get(
        InputIterator it, InputIterator end, std::ios_base& iosb,
        std::ios_base::iostate& state, double& val) const
    {
        get_and_check_eof(it, end, iosb, state, val);
        return it;
    }

    virtual InputIterator do_get(
        InputIterator it, InputIterator end, std::ios_base& iosb,
        std::ios_base::iostate& state, long double& val) const
    {
        get_and_check_eof(it, end, iosb, state, val);
        return it;
    }

//..............................................................................
    
private:
    template<class ValType> static ValType positive_nan()
    {
        // on some platforms quiet_NaN() is negative
        return (boost::math::copysign)(
            std::numeric_limits<ValType>::quiet_NaN(), 1);  
    }

    template<class ValType> void get_and_check_eof(
        InputIterator& it, InputIterator end, std::ios_base& iosb,
        std::ios_base::iostate& state, ValType& val) const
    {
        get_signed(it, end, iosb, state, val);
        if(it == end)
            state |= std::ios_base::eofbit;
    }

    template<class ValType> void get_signed(
        InputIterator& it, InputIterator end, std::ios_base& iosb,
        std::ios_base::iostate& state, ValType& val) const
    {
        const std::ctype<CharType>& ct
            = std::use_facet<std::ctype<CharType> >(iosb.getloc());

        char c = peek_char(it, end, ct);

        bool negative = (c == '-');

        if(negative || c == '+') {
            ++it;
            c = peek_char(it, end, ct);
            if(c == '-' || c == '+') {
                // without this check, "++5" etc would be accepted
                state |= std::ios_base::failbit;
                return;
            }
        }

        get_unsigned(it, end, iosb, ct, state, val);

        if(negative)
            val = (boost::math::changesign)(val);
    }

    template<class ValType> void get_unsigned(
        InputIterator& it, InputIterator end, std::ios_base& iosb,
        const std::ctype<CharType>& ct,
        std::ios_base::iostate& state, ValType& val) const
    {
        switch(peek_char(it, end, ct)) {

            case 'i': 
                get_i(it, end, ct, state, val);
                break;

            case 'n':
                get_n(it, end, ct, state, val);
                break;

            case 'q':
            case 's':
                get_q(it, end, ct, state, val);
                break;

            default:
                it = std::num_get<CharType, InputIterator>::do_get(
                        it, end, iosb, state, val);
                if((flags_ & legacy) && val == static_cast<ValType>(1)
                        && peek_char(it, end, ct) == '#')
                    get_one_hash(it, end, ct, state, val);
                break;
        }
    }

    //..........................................................................

    template<class ValType> void get_i(
        InputIterator& it, InputIterator end, const std::ctype<CharType>& ct,
        std::ios_base::iostate& state, ValType& val) const
    {
        if(!std::numeric_limits<ValType>::has_infinity
                || (flags_ & trap_infinity)) {
            state |= std::ios_base::failbit;
            return;
        }

        ++it;

        if(!match_string(it, end, ct, "nf")) {
            state |= std::ios_base::failbit;
            return;
        }

        if(peek_char(it, end, ct) != 'i') {
            val = std::numeric_limits<ValType>::infinity();     // "inf"
            return;
        }

        ++it;

        if(!match_string(it, end, ct, "nity")) {
            state |= std::ios_base::failbit;
            return;
        }

        val = std::numeric_limits<ValType>::infinity();         // "infinity"
    }

    template<class ValType> void get_n(
        InputIterator& it, InputIterator end, const std::ctype<CharType>& ct,
        std::ios_base::iostate& state, ValType& val) const
    {
        if(!std::numeric_limits<ValType>::has_quiet_NaN 
                || (flags_ & trap_nan)) {
            state |= std::ios_base::failbit;
            return;
        }

        ++it;
            
        if(!match_string(it, end, ct, "an")) {
            state |= std::ios_base::failbit;
            return;
        }

        switch(peek_char(it, end, ct)) {
            case 'q':
            case 's':
                if(flags_ && legacy)
                    ++it;
                break;              // "nanq", "nans"
                
            case '(': 
            {
                ++it;
                char c;
                while((c = peek_char(it, end, ct))
                        && c != ')' && c != ' ' && c != '\n' && c != '\t')
                    ++it;
                if(c != ')') {
                    state |= std::ios_base::failbit;
                    return;
                }
                ++it;           
                break;              // "nan(...)"
            }

            default:
                break;              // "nan"
        }

        val = positive_nan<ValType>();
    }

    template<class ValType> void get_q(
        InputIterator& it, InputIterator end, const std::ctype<CharType>& ct,
        std::ios_base::iostate& state, ValType& val) const
    {
        if(!std::numeric_limits<ValType>::has_quiet_NaN 
                || (flags_ & trap_nan) || !(flags_ & legacy)) {
            state |= std::ios_base::failbit;
            return;
        }

        ++it;

        if(!match_string(it, end, ct, "nan")) {
            state |= std::ios_base::failbit;
            return;
        }

        val = positive_nan<ValType>();      // qnan, snan
    }

    template<class ValType> void get_one_hash(
        InputIterator& it, InputIterator end, const std::ctype<CharType>& ct,
        std::ios_base::iostate& state, ValType& val) const
    {
        ++it;

        switch(peek_char(it, end, ct)) {
            case 'i':
                get_one_hash_i(it, end, ct, state, val);
                return;

            case 'q':
            case 's':
                if(std::numeric_limits<ValType>::has_quiet_NaN
                        && !(flags_ & trap_nan)) {
                    ++it;
                    if(match_string(it, end, ct, "nan")) {  
                                                        // "1.#QNAN", "1.#SNAN"
                        ++it;
                        val = positive_nan<ValType>();
                        return;
                    }
                }
                break;

            default:
                break;
        }

        state |= std::ios_base::failbit;
    }
   
    template<class ValType> void get_one_hash_i(
        InputIterator& it, InputIterator end, const std::ctype<CharType>& ct,
        std::ios_base::iostate& state, ValType& val) const
    {
        ++it;

        if(peek_char(it, end, ct) == 'n') {
            ++it;
            switch(peek_char(it, end, ct)) {
                case 'f':                                       // "1.#INF"
                    if(std::numeric_limits<ValType>::has_infinity
                            && !(flags_ & trap_infinity)) {
                        ++it;
                        val = std::numeric_limits<ValType>::infinity(); 
                        return;
                    }
                    break;

                case 'd':                                       // 1.#IND"
                    if(std::numeric_limits<ValType>::has_quiet_NaN
                            && !(flags_ & trap_nan)) {
                        ++it;
                        val = positive_nan<ValType>();
                        return;
                    }
                    break;

                default:
                    break;
            }
        }

        state |= std::ios_base::failbit;
    }

    //..........................................................................

    char peek_char(
        InputIterator& it, InputIterator end, 
        const std::ctype<CharType>& ct) const
    {
        if(it == end) return 0;
        return ct.narrow(ct.tolower(*it), 0);
    }

    bool match_string(
        InputIterator& it, InputIterator end,
        const std::ctype<CharType>& ct, const char* s) const
    {
        while(it != end && *s && *s == ct.narrow(ct.tolower(*it), 0)) {
            ++s;
            ++it;
        }
        return !*s;
    }

private:
    const int flags_;
};

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

}   // namespace math
}   // namespace spirit
}   // namespace boost

#ifdef _MSC_VER
#   pragma warning(pop)
#endif

#endif