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Move all the stream specific metafunctions to lexical_cast_stream_traits<Source, Target>

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Test stream traits for correctness and correct optimization detection

[SVN r81354]
This commit is contained in:
Antony Polukhin
2012-11-15 07:26:23 +00:00
parent cd5a55aab5
commit 2ea7487806
3 changed files with 263 additions and 90 deletions
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include/boost/lexical_cast.hpp
+107 -90
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@@ -504,6 +504,45 @@ namespace boost {
};
}
namespace detail // array_to_pointer_decay<T>
{
template<class T>
struct array_to_pointer_decay
{
typedef T type;
};
template<class T, std::size_t N>
struct array_to_pointer_decay<T[N]>
{
typedef const T * type;
};
}
namespace detail // is_this_float_conversion_optimized<Float, Char>
{
// this metafunction evaluates to true, if we have optimized comnversion
// from Float type to Char array.
// Must be in sync with lexical_stream_limited_src<Char, ...>::shl_real_type(...)
template <typename Float, typename Char>
struct is_this_float_conversion_optimized
{
typedef boost::type_traits::ice_and<
boost::is_float<Float>::value,
#if !defined(BOOST_LCAST_NO_WCHAR_T) && !defined(BOOST_NO_SWPRINTF) && !defined(__MINGW32__)
boost::type_traits::ice_or<
boost::type_traits::ice_eq<sizeof(Char), sizeof(char) >::value,
boost::is_same<Char, wchar_t>::value
>::value
#else
boost::type_traits::ice_eq<sizeof(Char), sizeof(char) >::value
#endif
> result_type;
BOOST_STATIC_CONSTANT(bool, value = (result_type::value) );
};
}
namespace detail // lcast_src_length
{
// Return max. length of string representation of Source;
@@ -613,6 +652,64 @@ namespace boost {
#endif // #ifndef BOOST_LCAST_NO_COMPILE_TIME_PRECISION
}
namespace detail // lexical_cast_stream_traits<Source, Target>
{
template <class Source, class Target>
struct lexical_cast_stream_traits {
typedef BOOST_DEDUCED_TYPENAME boost::detail::array_to_pointer_decay<Source>::type src;
typedef BOOST_DEDUCED_TYPENAME boost::remove_cv<src>::type no_cv_src;
typedef boost::detail::deduce_source_char<no_cv_src> deduce_src_char_metafunc;
typedef BOOST_DEDUCED_TYPENAME deduce_src_char_metafunc::type src_char_t;
typedef BOOST_DEDUCED_TYPENAME boost::detail::deduce_target_char<Target>::type target_char_t;
typedef BOOST_DEDUCED_TYPENAME boost::detail::widest_char<
target_char_t, src_char_t
>::type char_type;
#if !defined(BOOST_NO_CHAR16_T) && defined(BOOST_NO_UNICODE_LITERALS)
BOOST_STATIC_ASSERT_MSG(( !boost::is_same<char16_t, src_char_t>::value
&& !boost::is_same<char16_t, target_char_t>::value),
"Your compiler does not have full support for char16_t" );
#endif
#if !defined(BOOST_NO_CHAR32_T) && defined(BOOST_NO_UNICODE_LITERALS)
BOOST_STATIC_ASSERT_MSG(( !boost::is_same<char32_t, src_char_t>::value
&& !boost::is_same<char32_t, target_char_t>::value),
"Your compiler does not have full support for char32_t" );
#endif
typedef BOOST_DEDUCED_TYPENAME boost::detail::deduce_char_traits<
char_type, Target, no_cv_src
>::type traits;
typedef boost::type_traits::ice_and<
boost::is_same<char, src_char_t>::value, // source is not a wide character based type
boost::type_traits::ice_ne<sizeof(char), sizeof(target_char_t) >::value, // target type is based on wide character
boost::type_traits::ice_not<
boost::detail::is_char_or_wchar<no_cv_src>::value // single character widening is optimized
>::value // and does not requires stringbuffer
> is_string_widening_required_t;
typedef boost::type_traits::ice_not< boost::type_traits::ice_or<
boost::is_integral<no_cv_src>::value,
boost::detail::is_this_float_conversion_optimized<no_cv_src, char_type >::value,
boost::detail::is_char_or_wchar<
BOOST_DEDUCED_TYPENAME deduce_src_char_metafunc::stage1_type // if we did not get character type at stage1
>::value // then we have no optimization for that type
>::value > is_source_input_not_optimized_t;
// If we have an optimized conversion for
// Source, we do not need to construct stringbuf.
BOOST_STATIC_CONSTANT(bool, requires_stringbuf =
(boost::type_traits::ice_or<
is_string_widening_required_t::value, is_source_input_not_optimized_t::value
>::value)
);
typedef boost::detail::lcast_src_length<no_cv_src> len_t;
};
}
namespace detail // '0', '+' and '-' constants
{
template < typename Char > struct lcast_char_constants;
@@ -2040,18 +2137,6 @@ namespace boost {
namespace detail
{
template<class T>
struct array_to_pointer_decay
{
typedef T type;
};
template<class T, std::size_t N>
struct array_to_pointer_decay<T[N]>
{
typedef const T * type;
};
template<typename T>
struct is_stdstring
{
@@ -2115,28 +2200,6 @@ namespace boost {
);
};
// this metafunction evaluates to true, if we have optimized comnversion
// from Float type to Char array.
// Must be in sync with lexical_stream_limited_src<Char, ...>::shl_real_type(...)
template <typename Float, typename Char>
struct is_this_float_conversion_optimized
{
typedef boost::type_traits::ice_and<
boost::is_float<Float>::value,
#if !defined(BOOST_LCAST_NO_WCHAR_T) && !defined(BOOST_NO_SWPRINTF) && !defined(__MINGW32__)
boost::type_traits::ice_or<
boost::type_traits::ice_eq<sizeof(Char), sizeof(char) >::value,
boost::is_same<Char, wchar_t>::value
>::value
#else
boost::type_traits::ice_eq<sizeof(Char), sizeof(char) >::value
#endif
> result_type;
BOOST_STATIC_CONSTANT(bool, value = (result_type::value) );
};
template<typename Target, typename Source>
struct is_char_array_to_stdstring
{
@@ -2178,67 +2241,21 @@ namespace boost {
{
static inline Target lexical_cast_impl(const Source& arg)
{
typedef BOOST_DEDUCED_TYPENAME boost::detail::array_to_pointer_decay<Source>::type src;
typedef BOOST_DEDUCED_TYPENAME boost::remove_cv<src>::type no_cv_src;
typedef lexical_cast_stream_traits<Source, Target> stream_trait;
typedef boost::detail::deduce_source_char<no_cv_src> deduce_src_char_metafunc;
typedef BOOST_DEDUCED_TYPENAME deduce_src_char_metafunc::type src_char_t;
typedef BOOST_DEDUCED_TYPENAME boost::detail::deduce_target_char<Target>::type target_char_t;
typedef BOOST_DEDUCED_TYPENAME boost::detail::widest_char<
target_char_t, src_char_t
>::type char_type;
#if !defined(BOOST_NO_CHAR16_T) && defined(BOOST_NO_UNICODE_LITERALS)
BOOST_STATIC_ASSERT_MSG(( !boost::is_same<char16_t, src_char_t>::value
&& !boost::is_same<char16_t, target_char_t>::value),
"Your compiler does not have full support for char16_t" );
#endif
#if !defined(BOOST_NO_CHAR32_T) && defined(BOOST_NO_UNICODE_LITERALS)
BOOST_STATIC_ASSERT_MSG(( !boost::is_same<char32_t, src_char_t>::value
&& !boost::is_same<char32_t, target_char_t>::value),
"Your compiler does not have full support for char32_t" );
#endif
typedef BOOST_DEDUCED_TYPENAME boost::detail::deduce_char_traits<
char_type, Target, no_cv_src
>::type traits;
typedef boost::type_traits::ice_and<
boost::is_same<char, src_char_t>::value, // source is not a wide character based type
boost::type_traits::ice_ne<sizeof(char), sizeof(target_char_t) >::value, // target type is based on wide character
boost::type_traits::ice_not<
boost::detail::is_char_or_wchar<no_cv_src>::value // single character widening is optimized
>::value // and does not requires stringbuffer
> is_string_widening_required_t;
typedef boost::type_traits::ice_not< boost::type_traits::ice_or<
boost::is_integral<no_cv_src>::value,
boost::detail::is_this_float_conversion_optimized<no_cv_src, char_type >::value,
boost::detail::is_char_or_wchar<
BOOST_DEDUCED_TYPENAME deduce_src_char_metafunc::stage1_type // if we did not get character type at stage1
>::value // then we have no optimization for that type
>::value > is_source_input_not_optimized_t;
typedef detail::lexical_stream_limited_src<
BOOST_DEDUCED_TYPENAME stream_trait::char_type,
BOOST_DEDUCED_TYPENAME stream_trait::traits,
stream_trait::requires_stringbuf
> interpreter_type;
// Target type must be default constructible
Target result;
Target result;
// If we have an optimized conversion for
// Source, we do not need to construct stringbuf.
BOOST_STATIC_CONSTANT(bool, requires_stringbuf =
(boost::type_traits::ice_or<
is_string_widening_required_t::value, is_source_input_not_optimized_t::value
>::value)
);
typedef detail::lexical_stream_limited_src<char_type, traits, requires_stringbuf > interpreter_type;
BOOST_DEDUCED_TYPENAME stream_trait::char_type buf[stream_trait::len_t::value + 1];
stream_trait::len_t::check_coverage();
typedef detail::lcast_src_length<no_cv_src> lcast_src_length;
std::size_t const src_len = lcast_src_length::value;
char_type buf[src_len + 1];
lcast_src_length::check_coverage();
interpreter_type interpreter(buf, buf + src_len);
interpreter_type interpreter(buf, buf + stream_trait::len_t::value + 1);
// Disabling ADL, by directly specifying operators.
if(!(interpreter.operator <<(arg) && interpreter.operator >>(result)))