Subject: [Boost-commit] svn:boost r85482 - trunk/boost
From: antoshkka_at_[hidden]
Date: 2013-08-27 03:07:15
Author: apolukhin
Date: 2013-08-27 03:07:15 EDT (Tue, 27 Aug 2013)
New Revision: 85482
URL: http://svn.boost.org/trac/boost/changeset/85482
Log:
Improved some of the metaprogramming methods (refs #9046)
Text files modified:
trunk/boost/lexical_cast.hpp | 51 ++++++++++++++++++---------------------
1 files changed, 24 insertions(+), 27 deletions(-)
Modified: trunk/boost/lexical_cast.hpp
==============================================================================
--- trunk/boost/lexical_cast.hpp Mon Aug 26 17:36:22 2013 (r85481)
+++ trunk/boost/lexical_cast.hpp 2013-08-27 03:07:15 EDT (Tue, 27 Aug 2013) (r85482)
@@ -2133,24 +2133,17 @@
/*
* is_xchar_to_xchar<Target, Source>::value is true, when
* Target and Souce are the same char types, or when
- * Target and Souce are char types of the same size.
+ * Target and Souce are char types of the same size (signed char, unsigned char).
*/
template<typename Target, typename Source>
struct is_xchar_to_xchar
{
BOOST_STATIC_CONSTANT(bool, value =
(
- boost::type_traits::ice_or<
- boost::type_traits::ice_and<
- boost::is_same<Source,Target>::value,
- boost::detail::is_character<Target>::value
- >::value,
- boost::type_traits::ice_and<
- boost::type_traits::ice_eq< sizeof(char),sizeof(Target)>::value,
- boost::type_traits::ice_eq< sizeof(char),sizeof(Source)>::value,
- boost::detail::is_character<Target>::value,
- boost::detail::is_character<Source>::value
- >::value
+ boost::type_traits::ice_and<
+ boost::type_traits::ice_eq<sizeof(Source), sizeof(Target)>::value,
+ boost::detail::is_character<Target>::value,
+ boost::detail::is_character<Source>::value
>::value
)
);
@@ -2321,6 +2314,7 @@
{
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
@@ -2330,8 +2324,7 @@
>::value,
boost::type_traits::ice_not<
boost::is_same<Target, bool>::value
- >::value,
- boost::is_unsigned<Target>::value
+ >::value
>::value,
lexical_cast_dynamic_num_ignoring_minus<Target, Source>,
lexical_cast_dynamic_num_not_ignoring_minus<Target, Source>
@@ -2348,26 +2341,30 @@
typedef BOOST_DEDUCED_TYPENAME boost::detail::array_to_pointer_decay<Source>::type src;
typedef BOOST_DEDUCED_TYPENAME boost::type_traits::ice_or<
- boost::detail::is_xchar_to_xchar<Target, src >::value,
- boost::detail::is_char_array_to_stdstring<Target, src >::value,
- boost::type_traits::ice_and<
- boost::is_same<Target, src >::value,
- boost::detail::is_stdstring<Target >::value
- >::value
+ boost::detail::is_xchar_to_xchar<Target, src >::value,
+ boost::detail::is_char_array_to_stdstring<Target, src >::value,
+ boost::type_traits::ice_and<
+ boost::is_same<Target, src >::value,
+ boost::detail::is_stdstring<Target >::value
+ >::value
> shall_we_copy_t;
- typedef BOOST_DEDUCED_TYPENAME
- boost::detail::is_arithmetic_and_not_xchars<Target, src > shall_we_copy_with_dynamic_check_t;
+ typedef boost::detail::is_arithmetic_and_not_xchars<Target, src >
+ shall_we_copy_with_dynamic_check_t;
+ // We do evaluate second `if_` lazily to avoid unnecessary instantiations
+ // of `shall_we_copy_with_dynamic_check_t` and improve compilation times.
typedef BOOST_DEDUCED_TYPENAME boost::mpl::if_c<
shall_we_copy_t::value,
- boost::detail::lexical_cast_copy<src >,
- BOOST_DEDUCED_TYPENAME boost::mpl::if_c<
- shall_we_copy_with_dynamic_check_t::value,
+ boost::mpl::identity<boost::detail::lexical_cast_copy<src > >,
+ boost::mpl::if_<
+ shall_we_copy_with_dynamic_check_t,
boost::detail::lexical_cast_dynamic_num<Target, src >,
boost::detail::lexical_cast_do_cast<Target, src >
- >::type
- >::type caster_type;
+ >
+ >::type caster_type_lazy;
+
+ typedef BOOST_DEDUCED_TYPENAME caster_type_lazy::type caster_type;
return caster_type::lexical_cast_impl(arg);
}