boost/math/special_functions/nonfinite_num_facets.hpp
#ifndef BOOST_MATH_NONFINITE_NUM_FACETS_HPP #define BOOST_MATH_NONFINITE_NUM_FACETS_HPP // Copyright 2006 Johan Rade // Copyright 2012 K R Walker // Copyright 2011, 2012 Paul A. Bristow // 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) /* \file \brief non_finite_num facets for C99 standard output of infinity and NaN. \details See fuller documentation at Boost.Math Facets for Floating-Point Infinities and NaNs. */ #include <cstring> #include <ios> #include <limits> #include <locale> #include <boost/version.hpp> #include <boost/throw_exception.hpp> #include <boost/math/special_functions/fpclassify.hpp> #include <boost/math/special_functions/sign.hpp> #ifdef _MSC_VER # pragma warning(push) # pragma warning(disable : 4127) // conditional expression is constant. # pragma warning(disable : 4706) // assignment within conditional expression. #endif namespace boost { namespace math { // flags (enums can be ORed together) ----------------------------------- const int legacy = 0x1; //!< get facet will recognize most string representations of infinity and NaN. const int signed_zero = 0x2; //!< put facet will distinguish between positive and negative zero. const int trap_infinity = 0x4; /*!< put facet will throw an exception of type std::ios_base::failure when an attempt is made to format positive or negative infinity. get will set the fail bit of the stream when an attempt is made to parse a string that represents positive or negative sign infinity. */ const int trap_nan = 0x8; /*!< put facet will throw an exception of type std::ios_base::failure when an attempt is made to format positive or negative NaN. get will set the fail bit of the stream when an attempt is made to parse a string that represents positive or negative sign infinity. */ // 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 { static const CharType prefix_plus[2] = { '+', '\0' }; static const CharType prefix_minus[2] = { '-', '\0' }; static const CharType body_inf[4] = { 'i', 'n', 'f', '\0' }; static const CharType body_nan[4] = { 'n', 'a', 'n', '\0' }; static const CharType* null_string = 0; switch((boost::math::fpclassify)(val)) { case FP_INFINITE: if(flags_ & trap_infinity) { BOOST_THROW_EXCEPTION(std::ios_base::failure("Infinity")); } else if((boost::math::signbit)(val)) { // negative infinity. put_num_and_fill(it, iosb, prefix_minus, body_inf, fill, val); } else if(iosb.flags() & std::ios_base::showpos) { // Explicit "+inf" wanted. put_num_and_fill(it, iosb, prefix_plus, body_inf, fill, val); } else { // just "inf" wanted. put_num_and_fill(it, iosb, null_string, body_inf, fill, val); } break; case FP_NAN: if(flags_ & trap_nan) { BOOST_THROW_EXCEPTION(std::ios_base::failure("NaN")); } else if((boost::math::signbit)(val)) { // negative so "-nan". put_num_and_fill(it, iosb, prefix_minus, body_nan, fill, val); } else if(iosb.flags() & std::ios_base::showpos) { // explicit "+nan" wanted. put_num_and_fill(it, iosb, prefix_plus, body_nan, fill, val); } else { // Just "nan". put_num_and_fill(it, iosb, null_string, body_nan, fill, val); } break; case FP_ZERO: if((flags_ & signed_zero) && ((boost::math::signbit)(val))) { // Flag set to distinguish between positive and negative zero. // But string "0" should have stuff after decimal point if setprecision and/or exp format. std::basic_ostringstream<CharType> zeros; // Needs to be CharType version. // Copy flags, fill, width and precision. zeros.flags(iosb.flags()); zeros.unsetf(std::ios::showpos); // Ignore showpos because must be negative. zeros.precision(iosb.precision()); //zeros.width is set by put_num_and_fill zeros.fill(static_cast<char>(fill)); zeros << ValType(0); put_num_and_fill(it, iosb, prefix_minus, zeros.str().c_str(), fill, val); } else { // Output the platform default for positive and negative zero. put_num_and_fill(it, iosb, null_string, null_string, fill, val); } break; default: // Normal non-zero finite value. it = std::num_put<CharType, OutputIterator>::do_put(it, iosb, fill, val); break; } } template<class ValType> void put_num_and_fill( OutputIterator& it, std::ios_base& iosb, const CharType* prefix, const CharType* body, CharType fill, ValType val) const { int prefix_length = prefix ? (int)std::char_traits<CharType>::length(prefix) : 0; int body_length = body ? (int)std::char_traits<CharType>::length(body) : 0; int width = prefix_length + body_length; 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(body || prefix) { // adjust == std::ios_base::right, so leading fill needed. if(adjust != std::ios_base::internal && adjust != std::ios_base::left) put_fill(it, iosb, fill, width); } if(prefix) { // Adjust width for prefix. while(*prefix) *it = *(prefix++); iosb.width( iosb.width() - prefix_length ); width -= prefix_length; } if(body) { // if(adjust == std::ios_base::internal) { // Put fill between sign and digits. put_fill(it, iosb, fill, width); } if(iosb.flags() & std::ios_base::uppercase) { while(*body) *it = ct.toupper(*(body++)); } else { while(*body) *it = *(body++); } if(adjust == std::ios_base::left) put_fill(it, iosb, fill, width); } else { it = std::num_put<CharType, OutputIterator>::do_put(it, iosb, fill, val); } } void put_fill( OutputIterator& it, std::ios_base& iosb, CharType fill, int width) const { // Insert fill chars. for(std::streamsize i = iosb.width() - static_cast<std::streamsize>(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: // float, double and long double versions of do_get. 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() may be negative. return (boost::math::copysign)( std::numeric_limits<ValType>::quiet_NaN(), static_cast<ValType>(1) ); // static_cast<ValType>(1) added Paul A. Bristow 5 Apr 11 } 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); } } // void get_signed template<class ValType> void get_unsigned ( //! Get an unsigned floating-point value into val, //! but checking for letters indicating non-finites. 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: // Got a normal floating-point value into val. 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; } } // get_unsigned //.......................................................................... template<class ValType> void get_i ( // Get the rest of all strings starting with 'i', expect "inf", "infinity". 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")) { // Expected "infinity" state |= std::ios_base::failbit; return; } val = std::numeric_limits<ValType>::infinity(); // "infinity" } // void get_i template<class ValType> void get_n ( // Get expected strings after 'n', "nan", "nanq", "nans", "nan(...)" 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 '(': // Optional payload field in (...) follows. { ++it; char c; while((c = peek_char(it, end, ct)) && c != ')' && c != ' ' && c != '\n' && c != '\t') ++it; if(c != ')') { // Optional payload field terminator missing! state |= std::ios_base::failbit; return; } ++it; break; // "nan(...)" } default: break; // "nan" } val = positive_nan<ValType>(); } // void get_n template<class ValType> void get_q ( // Get expected rest of string starting with 'q': "qnan". 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" } // void get_q template<class ValType> void get_one_hash ( // Get expected string after having read "1.#": "1.#IND", "1.#QNAN", "1.#SNAN". 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': // from IND (indeterminate), considered same a QNAN. get_one_hash_i(it, end, ct, state, val); // "1.#IND" return; case 'q': // from QNAN case 's': // from SNAN - treated the same as QNAN. if(std::numeric_limits<ValType>::has_quiet_NaN && !(flags_ & trap_nan)) { ++it; if(match_string(it, end, ct, "nan")) { // "1.#QNAN", "1.#SNAN" // ++it; // removed as caused assert() cannot increment iterator). // (match_string consumes string, so not needed?). // https://svn.boost.org/trac/boost/ticket/5467 // Change in nonfinite_num_facet.hpp Paul A. Bristow 11 Apr 11 makes legacy_test.cpp work OK. val = positive_nan<ValType>(); // "1.#QNAN" return; } } break; default: break; } state |= std::ios_base::failbit; } // void get_one_hash template<class ValType> void get_one_hash_i ( // Get expected strings after 'i', "1.#INF", 1.#IND". 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; } // void get_one_hash_i //.......................................................................... char peek_char ( //! \return next char in the input buffer, ensuring lowercase (but do not 'consume' char). InputIterator& it, InputIterator end, const std::ctype<CharType>& ct ) const { if(it == end) return 0; return ct.narrow(ct.tolower(*it), 0); // Always tolower to ensure case insensitive. } bool match_string ( //! Match remaining chars to expected string (case insensitive), //! consuming chars that match OK. //! \return true if matched expected string, else false. 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; } // bool match_string private: const int flags_; }; // //------------------------------------------------------------------------------ } // namespace math } // namespace boost #ifdef _MSC_VER # pragma warning(pop) #endif #endif // BOOST_MATH_NONFINITE_NUM_FACETS_HPP