/Src/Dependencies/Boost/boost/spirit/home/karma/numeric/detail/real_utils.hpp
http://hadesmem.googlecode.com/ · C++ Header · 185 lines · 131 code · 24 blank · 30 comment · 32 complexity · 0a07f5ee15341ee238986be60305d6e0 MD5 · raw file
- // Copyright (c) 2001-2011 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_REAL_UTILS_FEB_23_2007_0841PM)
- #define BOOST_SPIRIT_KARMA_REAL_UTILS_FEB_23_2007_0841PM
- #if defined(_MSC_VER)
- #pragma once
- #endif
- #include <boost/config.hpp>
- #include <boost/config/no_tr1/cmath.hpp>
- #include <boost/detail/workaround.hpp>
- #include <boost/limits.hpp>
- #include <boost/spirit/home/support/char_class.hpp>
- #include <boost/spirit/home/support/unused.hpp>
- #include <boost/spirit/home/support/detail/pow10.hpp>
- #include <boost/spirit/home/support/detail/sign.hpp>
- #include <boost/spirit/home/karma/detail/generate_to.hpp>
- #include <boost/spirit/home/karma/detail/string_generate.hpp>
- #include <boost/spirit/home/karma/numeric/detail/numeric_utils.hpp>
- namespace boost { namespace spirit { namespace karma
- {
- ///////////////////////////////////////////////////////////////////////////
- //
- // The real_inserter template takes care of the floating point number to
- // string conversion. The Policies template parameter is used to allow
- // customization of the formatting process
- //
- ///////////////////////////////////////////////////////////////////////////
- template <typename T>
- struct real_policies;
- template <typename T
- , typename Policies = real_policies<T>
- , typename CharEncoding = unused_type
- , typename Tag = unused_type>
- struct real_inserter
- {
- template <typename OutputIterator, typename U>
- static bool
- call (OutputIterator& sink, U n, Policies const& p = Policies())
- {
- if (traits::test_nan(n)) {
- return Policies::template nan<CharEncoding, Tag>(
- sink, n, p.force_sign(n));
- }
- else if (traits::test_infinite(n)) {
- return Policies::template inf<CharEncoding, Tag>(
- sink, n, p.force_sign(n));
- }
- return p.template call<real_inserter>(sink, n, p);
- }
- #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
- # pragma warning(push)
- # pragma warning(disable: 4100) // 'p': unreferenced formal parameter
- # pragma warning(disable: 4127) // conditional expression is constant
- # pragma warning(disable: 4267) // conversion from 'size_t' to 'unsigned int', possible loss of data
- #endif
- ///////////////////////////////////////////////////////////////////////
- // This is the workhorse behind the real generator
- ///////////////////////////////////////////////////////////////////////
- template <typename OutputIterator, typename U>
- static bool
- call_n (OutputIterator& sink, U n, Policies const& p)
- {
- // prepare sign and get output format
- bool force_sign = p.force_sign(n);
- bool sign_val = false;
- int flags = p.floatfield(n);
- if (traits::test_negative(n))
- {
- n = -n;
- sign_val = true;
- }
- // The scientific representation requires the normalization of the
- // value to convert.
- // get correct precision for generated number
- unsigned precision = p.precision(n);
- if (std::numeric_limits<U>::digits10)
- {
- // limit generated precision to digits10, if defined
- precision = (std::min)(precision,
- (unsigned)std::numeric_limits<U>::digits10 + 1);
- }
- // allow for ADL to find the correct overloads for log10 et.al.
- using namespace std;
- U dim = 0;
- if (0 == (Policies::fmtflags::fixed & flags) && !traits::test_zero(n))
- {
- dim = log10(n);
- if (dim > 0)
- n /= spirit::traits::pow10<U>(traits::truncate_to_long::call(dim));
- else if (n < 1.) {
- long exp = traits::truncate_to_long::call(-dim);
- if (exp != -dim)
- ++exp;
- dim = -exp;
- n *= spirit::traits::pow10<U>(exp);
- }
- }
- // prepare numbers (sign, integer and fraction part)
- U integer_part;
- U precexp = spirit::traits::pow10<U>(precision);
- U fractional_part = modf(n, &integer_part);
- fractional_part = floor(fractional_part * precexp + U(0.5));
- if (fractional_part >= precexp)
- {
- fractional_part = floor(fractional_part - precexp);
- integer_part += 1; // handle rounding overflow
- }
- // if trailing zeros are to be omitted, normalize the precision and
- // fractional part
- U long_int_part = floor(integer_part);
- U long_frac_part = fractional_part;
- unsigned prec = precision;
- if (!p.trailing_zeros(n))
- {
- U frac_part_floor = long_frac_part;
- if (0 != long_frac_part) {
- // remove the trailing zeros
- while (0 != prec &&
- 0 == traits::remainder<10>::call(long_frac_part))
- {
- long_frac_part = traits::divide<10>::call(long_frac_part);
- --prec;
- }
- }
- else {
- // if the fractional part is zero, we don't need to output
- // any additional digits
- prec = 0;
- }
- if (precision != prec)
- {
- long_frac_part = frac_part_floor /
- spirit::traits::pow10<U>(precision-prec);
- }
- }
- // call the actual generating functions to output the different parts
- if (sign_val && traits::test_zero(long_int_part) &&
- traits::test_zero(long_frac_part))
- {
- sign_val = false; // result is zero, no sign please
- }
- // generate integer part
- bool r = p.integer_part(sink, long_int_part, sign_val, force_sign);
- // generate decimal point
- r = r && p.dot(sink, long_frac_part, precision);
- // generate fractional part with the desired precision
- r = r && p.fraction_part(sink, long_frac_part, prec, precision);
- if (r && 0 == (Policies::fmtflags::fixed & flags)) {
- return p.template exponent<CharEncoding, Tag>(sink,
- traits::truncate_to_long::call(dim));
- }
- return r;
- }
- #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
- # pragma warning(pop)
- #endif
- };
- }}}
- #endif