comparison DEPENDENCIES/generic/include/boost/spirit/home/karma/numeric/real_policies.hpp @ 16:2665513ce2d3

Add boost headers

+//  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_POLICIES_MAR_02_2007_0936AM)
+#define BOOST_SPIRIT_KARMA_REAL_POLICIES_MAR_02_2007_0936AM
+
+#if defined(_MSC_VER)
+#pragma once
+#endif
+
+#include <boost/config/no_tr1/cmath.hpp>
+#include <boost/math/special_functions/fpclassify.hpp>
+#include <boost/type_traits/remove_const.hpp>
+
+#include <boost/spirit/home/support/char_class.hpp>
+#include <boost/spirit/home/karma/generator.hpp>
+#include <boost/spirit/home/karma/char.hpp>
+#include <boost/spirit/home/karma/numeric/int.hpp>
+#include <boost/spirit/home/karma/numeric/detail/real_utils.hpp>
+
+#include <boost/mpl/bool.hpp>
+
+namespace boost { namespace spirit { namespace karma 
+{
+    ///////////////////////////////////////////////////////////////////////////
+    //
+    //  real_policies, if you need special handling of your floating
+    //  point numbers, just overload this policy class and use it as a template
+    //  parameter to the karma::real_generator floating point specifier:
+    //
+    //      template <typename T>
+    //      struct scientific_policy : karma::real_policies<T>
+    //      {
+    //          //  we want the numbers always to be in scientific format
+    //          static int floatfield(T n) { return fmtflags::scientific; }
+    //      };
+    //
+    //      typedef 
+    //          karma::real_generator<double, scientific_policy<double> > 
+    //      science_type;
+    //
+    //      karma::generate(sink, science_type(), 1.0); // will output: 1.0e00
+    //
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename T>
+    struct real_policies
+    {
+        ///////////////////////////////////////////////////////////////////////
+        // Expose the data type the generator is targeted at
+        ///////////////////////////////////////////////////////////////////////
+        typedef T value_type;
+
+        ///////////////////////////////////////////////////////////////////////
+        //  By default the policy doesn't require any special iterator 
+        //  functionality. The floating point generator exposes its properties
+        //  from here, so this needs to be updated in case other properties
+        //  need to be implemented.
+        ///////////////////////////////////////////////////////////////////////
+        typedef mpl::int_<generator_properties::no_properties> properties;
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Specifies, which representation type to use during output 
+        //  generation.
+        ///////////////////////////////////////////////////////////////////////
+        struct fmtflags
+        {
+            enum {
+                scientific = 0,   // Generate floating-point values in scientific 
+                                  // format (with an exponent field).
+                fixed = 1         // Generate floating-point values in fixed-point 
+                                  // format (with no exponent field). 
+            };
+        };
+
+        ///////////////////////////////////////////////////////////////////////
+        //  This is the main function used to generate the output for a 
+        //  floating point number. It is called by the real generator in order 
+        //  to perform the conversion. In theory all of the work can be 
+        //  implemented here, but it is the easiest to use existing 
+        //  functionality provided by the type specified by the template 
+        //  parameter `Inserter`. 
+        //
+        //      sink: the output iterator to use for generation
+        //      n:    the floating point number to convert 
+        //      p:    the instance of the policy type used to instantiate this 
+        //            floating point generator.
+        ///////////////////////////////////////////////////////////////////////
+        template <typename Inserter, typename OutputIterator, typename Policies>
+        static bool
+        call (OutputIterator& sink, T n, Policies const& p)
+        {
+            return Inserter::call_n(sink, n, p);
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  The default behavior is to not to require generating a sign. If 
+        //  'force_sign()' returns true, then all generated numbers will 
+        //  have a sign ('+' or '-', zeros will have a space instead of a sign)
+        // 
+        //      n     The floating point number to output. This can be used to 
+        //            adjust the required behavior depending on the value of 
+        //            this number.
+        ///////////////////////////////////////////////////////////////////////
+        static bool force_sign(T)
+        {
+            return false;
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Return whether trailing zero digits have to be emitted in the 
+        //  fractional part of the output. If set, this flag instructs the 
+        //  floating point generator to emit trailing zeros up to the required 
+        //  precision digits (as returned by the precision() function).
+        // 
+        //      n     The floating point number to output. This can be used to 
+        //            adjust the required behavior depending on the value of 
+        //            this number.
+        ///////////////////////////////////////////////////////////////////////
+        static bool trailing_zeros(T)
+        {
+            // the default behavior is not to generate trailing zeros
+            return false;
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Decide, which representation type to use in the generated output.
+        //
+        //  By default all numbers having an absolute value of zero or in 
+        //  between 0.001 and 100000 will be generated using the fixed format, 
+        //  all others will be generated using the scientific representation.
+        //
+        //  The function trailing_zeros() can be used to force the output of 
+        //  trailing zeros in the fractional part up to the number of digits 
+        //  returned by the precision() member function. The default is not to 
+        //  generate the trailing zeros.
+        //  
+        //      n     The floating point number to output. This can be used to 
+        //            adjust the formatting flags depending on the value of 
+        //            this number.
+        ///////////////////////////////////////////////////////////////////////
+        static int floatfield(T n)
+        {
+            if (traits::test_zero(n))
+                return fmtflags::fixed;
+
+            T abs_n = traits::get_absolute_value(n);
+            return (abs_n >= 1e5 || abs_n < 1e-3) 
+              ? fmtflags::scientific : fmtflags::fixed;
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Return the maximum number of decimal digits to generate in the 
+        //  fractional part of the output.
+        //  
+        //      n     The floating point number to output. This can be used to 
+        //            adjust the required precision depending on the value of 
+        //            this number. If the trailing zeros flag is specified the
+        //            fractional part of the output will be 'filled' with 
+        //            zeros, if appropriate
+        //
+        //  Note:     If the trailing_zeros flag is not in effect additional
+        //            comments apply. See the comment for the fraction_part()
+        //            function below. Moreover, this precision will be limited
+        //            to the value of std::numeric_limits<T>::digits10 + 1
+        ///////////////////////////////////////////////////////////////////////
+        static unsigned precision(T)
+        {
+            // by default, generate max. 3 fractional digits
+            return 3;
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Generate the integer part of the number.
+        //
+        //      sink       The output iterator to use for generation
+        //      n          The absolute value of the integer part of the floating
+        //                 point number to convert (always non-negative).
+        //      sign       The sign of the overall floating point number to
+        //                 convert.
+        //      force_sign Whether a sign has to be generated even for
+        //                 non-negative numbers. Note, that force_sign will be
+        //                 set to false for zero floating point values.
+        ///////////////////////////////////////////////////////////////////////
+        template <typename OutputIterator>
+        static bool integer_part (OutputIterator& sink, T n, bool sign
+          , bool force_sign)
+        {
+            return sign_inserter::call(
+                      sink, traits::test_zero(n), sign, force_sign, force_sign) &&
+                   int_inserter<10>::call(sink, n);
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Generate the decimal point.
+        //
+        //      sink  The output iterator to use for generation
+        //      n     The fractional part of the floating point number to 
+        //            convert. Note that this number is scaled such, that 
+        //            it represents the number of units which correspond
+        //            to the value returned from the precision() function 
+        //            earlier. I.e. a fractional part of 0.01234 is
+        //            represented as 1234 when the 'Precision' is 5.
+        //      precision   The number of digits to emit as returned by the 
+        //                  function 'precision()' above
+        //
+        //            This is given to allow to decide, whether a decimal point
+        //            has to be generated at all.
+        //
+        //  Note:     If the trailing_zeros flag is not in effect additional
+        //            comments apply. See the comment for the fraction_part()
+        //            function below.
+        ///////////////////////////////////////////////////////////////////////
+        template <typename OutputIterator>
+        static bool dot (OutputIterator& sink, T /*n*/, unsigned /*precision*/)
+        {
+            return char_inserter<>::call(sink, '.');  // generate the dot by default 
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Generate the fractional part of the number.
+        //
+        //      sink  The output iterator to use for generation
+        //      n     The fractional part of the floating point number to 
+        //            convert. This number is scaled such, that it represents 
+        //            the number of units which correspond to the 'Precision'. 
+        //            I.e. a fractional part of 0.01234 is represented as 1234 
+        //            when the 'precision_' parameter is 5.
+        //      precision_  The corrected number of digits to emit (see note 
+        //                  below)
+        //      precision   The number of digits to emit as returned by the 
+        //                  function 'precision()' above
+        //
+        //  Note: If trailing_zeros() does not return true the 'precision_' 
+        //        parameter will have been corrected from the value the 
+        //        precision() function returned earlier (defining the maximal 
+        //        number of fractional digits) in the sense, that it takes into 
+        //        account trailing zeros. I.e. a floating point number 0.0123 
+        //        and a value of 5 returned from precision() will result in:
+        //
+        //        trailing_zeros is not specified:
+        //            n           123
+        //            precision_  4
+        //
+        //        trailing_zeros is specified:
+        //            n           1230
+        //            precision_  5
+        //
+        ///////////////////////////////////////////////////////////////////////
+        template <typename OutputIterator>
+        static bool fraction_part (OutputIterator& sink, T n
+          , unsigned precision_, unsigned precision)
+        {
+            // allow for ADL to find the correct overload for floor and log10
+            using namespace std;
+
+            // The following is equivalent to:
+            //    generate(sink, right_align(precision, '0')[ulong], n);
+            // but it's spelled out to avoid inter-modular dependencies.
+
+            typename remove_const<T>::type digits = 
+                (traits::test_zero(n) ? 0 : floor(log10(n))) + 1;
+            bool r = true;
+            for (/**/; r && digits < precision_; digits = digits + 1)
+                r = char_inserter<>::call(sink, '0');
+            if (precision && r)
+                r = int_inserter<10>::call(sink, n);
+            return r;
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Generate the exponential part of the number (this is called only 
+        //  if the floatfield() function returned the 'scientific' flag).
+        //
+        //      sink  The output iterator to use for generation
+        //      n     The (signed) exponential part of the floating point 
+        //            number to convert. 
+        //
+        //  The Tag template parameter is either of the type unused_type or
+        //  describes the character class and conversion to be applied to any 
+        //  output possibly influenced by either the lower[...] or upper[...] 
+        //  directives.
+        ///////////////////////////////////////////////////////////////////////
+        template <typename CharEncoding, typename Tag, typename OutputIterator>
+        static bool exponent (OutputIterator& sink, long n)
+        {
+            long abs_n = traits::get_absolute_value(n);
+            bool r = char_inserter<CharEncoding, Tag>::call(sink, 'e') &&
+                     sign_inserter::call(sink, traits::test_zero(n)
+                        , traits::test_negative(n), false);
+
+            // the C99 Standard requires at least two digits in the exponent
+            if (r && abs_n < 10)
+                r = char_inserter<CharEncoding, Tag>::call(sink, '0');
+            return r && int_inserter<10>::call(sink, abs_n);
+        }
+
+        ///////////////////////////////////////////////////////////////////////
+        //  Print the textual representations for non-normal floats (NaN and 
+        //  Inf)
+        //
+        //      sink       The output iterator to use for generation
+        //      n          The (signed) floating point number to convert. 
+        //      force_sign Whether a sign has to be generated even for 
+        //                 non-negative numbers
+        //
+        //  The Tag template parameter is either of the type unused_type or
+        //  describes the character class and conversion to be applied to any 
+        //  output possibly influenced by either the lower[...] or upper[...] 
+        //  directives.
+        //
+        //  Note: These functions get called only if fpclassify() returned 
+        //        FP_INFINITY or FP_NAN.
+        ///////////////////////////////////////////////////////////////////////
+        template <typename CharEncoding, typename Tag, typename OutputIterator>
+        static bool nan (OutputIterator& sink, T n, bool force_sign)
+        {
+            return sign_inserter::call(
+                        sink, false, traits::test_negative(n), force_sign) &&
+                   string_inserter<CharEncoding, Tag>::call(sink, "nan");
+        }
+
+        template <typename CharEncoding, typename Tag, typename OutputIterator>
+        static bool inf (OutputIterator& sink, T n, bool force_sign)
+        {
+            return sign_inserter::call(
+                        sink, false, traits::test_negative(n), force_sign) &&
+                   string_inserter<CharEncoding, Tag>::call(sink, "inf");
+        }
+    };
+}}}
+
+#endif // defined(BOOST_SPIRIT_KARMA_REAL_POLICIES_MAR_02_2007_0936AM)