Imported Upstream version 1.57.0upstream/1.57.0

1 files changed, 179 insertions, 0 deletions

diff --git a/boost/lexical_cast/detail/converter_numeric.hpp b/boost/lexical_cast/detail/converter_numeric.hpp
new file mode 100644
index 0000000000..83600f7e0b
--- /dev/null
+++ b/boost/lexical_cast/detail/converter_numeric.hpp
@@ -0,0 +1,179 @@
+// Copyright Kevlin Henney, 2000-2005.
+// Copyright Alexander Nasonov, 2006-2010.
+// Copyright Antony Polukhin, 2011-2014.
+//
+// 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)
+//
+// what:  lexical_cast custom keyword cast
+// who:   contributed by Kevlin Henney,
+//        enhanced with contributions from Terje Slettebo,
+//        with additional fixes and suggestions from Gennaro Prota,
+//        Beman Dawes, Dave Abrahams, Daryle Walker, Peter Dimov,
+//        Alexander Nasonov, Antony Polukhin, Justin Viiret, Michael Hofmann,
+//        Cheng Yang, Matthew Bradbury, David W. Birdsall, Pavel Korzh and other Boosters
+// when:  November 2000, March 2003, June 2005, June 2006, March 2011 - 2014
+
+#ifndef BOOST_LEXICAL_CAST_DETAIL_CONVERTER_NUMERIC_HPP
+#define BOOST_LEXICAL_CAST_DETAIL_CONVERTER_NUMERIC_HPP
+
+#include <boost/config.hpp>
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#   pragma once
+#endif
+
+#include <boost/limits.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/type_traits/ice.hpp>
+#include <boost/type_traits/make_unsigned.hpp>
+#include <boost/type_traits/is_signed.hpp>
+#include <boost/type_traits/is_integral.hpp>
+#include <boost/type_traits/is_arithmetic.hpp>
+#include <boost/type_traits/is_base_of.hpp>
+
+#include <boost/numeric/conversion/cast.hpp>
+
+namespace boost { namespace detail {
+
+template <class Source >
+struct detect_precision_loss
+{
+    typedef Source source_type;
+    typedef boost::numeric::Trunc<Source> Rounder;
+    typedef BOOST_DEDUCED_TYPENAME mpl::if_<
+        boost::is_arithmetic<Source>, Source, Source const&
+    >::type argument_type ;
+
+    static inline source_type nearbyint(argument_type s, bool& is_ok) BOOST_NOEXCEPT {
+        const source_type near_int = Rounder::nearbyint(s);
+        if (near_int && is_ok) {
+            const source_type orig_div_round = s / near_int;
+            const source_type eps = std::numeric_limits<source_type>::epsilon();
+
+            is_ok = !((orig_div_round > 1 ? orig_div_round - 1 : 1 - orig_div_round) > eps);
+        }
+
+        return s;
+    }
+
+    typedef typename Rounder::round_style round_style;
+};
+
+template <typename Base, class Source>
+struct fake_precision_loss: public Base
+{
+    typedef Source source_type ;
+    typedef BOOST_DEDUCED_TYPENAME mpl::if_<
+        boost::is_arithmetic<Source>, Source, Source const&
+    >::type argument_type ;
+
+    static inline source_type nearbyint(argument_type s, bool& /*is_ok*/) BOOST_NOEXCEPT {
+        return s;
+    }
+};
+
+struct nothrow_overflow_handler
+{
+    inline bool operator() ( boost::numeric::range_check_result r ) const BOOST_NOEXCEPT {
+        return (r == boost::numeric::cInRange);
+    }
+};
+
+template <typename Target, typename Source>
+inline bool noexcept_numeric_convert(const Source& arg, Target& result) BOOST_NOEXCEPT {
+    typedef boost::numeric::converter<
+            Target,
+            Source,
+            boost::numeric::conversion_traits<Target, Source >,
+            nothrow_overflow_handler,
+            detect_precision_loss<Source >
+    > converter_orig_t;
+
+    typedef BOOST_DEDUCED_TYPENAME boost::mpl::if_c<
+        boost::is_base_of< detect_precision_loss<Source >, converter_orig_t >::value,
+        converter_orig_t,
+        fake_precision_loss<converter_orig_t, Source>
+    >::type converter_t;
+
+    bool res = nothrow_overflow_handler()(converter_t::out_of_range(arg));
+    result = converter_t::low_level_convert(converter_t::nearbyint(arg, res));
+    return res;
+}
+
+template <typename Target, typename Source>
+struct lexical_cast_dynamic_num_not_ignoring_minus
+{
+    static inline bool try_convert(const Source &arg, Target& result) BOOST_NOEXCEPT {
+        return noexcept_numeric_convert<Target, Source >(arg, result);
+    }
+};
+
+template <typename Target, typename Source>
+struct lexical_cast_dynamic_num_ignoring_minus
+{
+    static inline bool try_convert(const Source &arg, Target& result) BOOST_NOEXCEPT {
+        typedef BOOST_DEDUCED_TYPENAME boost::mpl::eval_if_c<
+                boost::is_float<Source>::value,
+                boost::mpl::identity<Source>,
+                boost::make_unsigned<Source>
+        >::type usource_t;
+
+        if (arg < 0) {
+            const bool res = noexcept_numeric_convert<Target, usource_t>(0u - arg, result);
+            result = static_cast<Target>(0u - result);
+            return res;
+        } else {
+            return noexcept_numeric_convert<Target, usource_t>(arg, result);
+        }
+    }
+};
+
+/*
+ * lexical_cast_dynamic_num follows the rules:
+ * 1) If Source can be converted to Target without precision loss and
+ * without overflows, then assign Source to Target and return
+ *
+ * 2) If Source is less than 0 and Target is an unsigned integer,
+ * then negate Source, check the requirements of rule 1) and if
+ * successful, assign static_casted Source to Target and return
+ *
+ * 3) Otherwise throw a bad_lexical_cast exception
+ *
+ *
+ * Rule 2) required because boost::lexical_cast has the behavior of
+ * stringstream, which uses the rules of scanf for conversions. And
+ * in the C99 standard for unsigned input value minus sign is
+ * optional, so if a negative number is read, no errors will arise
+ * and the result will be the two's complement.
+ */
+template <typename Target, typename Source>
+struct dynamic_num_converter_impl
+{
+    static inline bool try_convert(const Source &arg, Target& result) BOOST_NOEXCEPT {
+        typedef BOOST_DEDUCED_TYPENAME boost::mpl::if_c<
+            boost::type_traits::ice_and<
+                boost::is_unsigned<Target>::value,
+                boost::type_traits::ice_or<
+                    boost::is_signed<Source>::value,
+                    boost::is_float<Source>::value
+                >::value,
+                boost::type_traits::ice_not<
+                    boost::is_same<Source, bool>::value
+                >::value,
+                boost::type_traits::ice_not<
+                    boost::is_same<Target, bool>::value
+                >::value
+            >::value,
+            lexical_cast_dynamic_num_ignoring_minus<Target, Source>,
+            lexical_cast_dynamic_num_not_ignoring_minus<Target, Source>
+        >::type caster_type;
+
+        return caster_type::try_convert(arg, result);
+    }
+};
+
+}} // namespace boost::detail
+
+#endif // BOOST_LEXICAL_CAST_DETAIL_CONVERTER_NUMERIC_HPP
+