Do not use custom traits from input/output types as it leads to linktime or runtime errors (fixes #46) (#74)

Author: apolukhin

doc/lexical_cast.qbk

@@ -239,10 +239,13 @@ limitation of compiler options that you use.
 
     * Significant rewrite of the internal logic to separate optimized and C++ Standard Library IO-based streams:
       * C++ Standard Library based streams now constructed in less cases leading to [*better performance];
-      * less template instantiations and simpler maintainance;
+      * less template instantiations and simpler code;
+      * always use `std::char_traits` (do not use custom traits from input/output types as it leads to linktime or runtime errors);
       * support for `volatile` input types was dropped, following the C++ Standard Library trend.
     * Optimized conversions from std::basic_string_view and boost::basic_string_view
-    * Dropped dependency on Boost.NumericConversion and Boost.MPL
+    * Dropped dependency on Boost.NumericConversion and Boost.MPL. Fixed some cases
+      of converting floting point types to arithmetics.
+    * The library now works fine with `-fno-sanitize-recover=integer`.
 
 * [*boost 1.84.0 :]
 

include/boost/lexical_cast/detail/converter_lexical.hpp

@@ -322,47 +322,6 @@ namespace boost {
         };
     }
 
-    namespace detail // extract_char_traits template
-    {
-        // We are attempting to get char_traits<> from T
-        // template parameter. Otherwise we'll be using std::char_traits<Char>
-        template < class Char, class T >
-        struct extract_char_traits
-                : boost::false_type
-        {
-            typedef std::char_traits< Char > trait_t;
-        };
-
-        template < class Char, class Traits, class Alloc >
-        struct extract_char_traits< Char, std::basic_string< Char, Traits, Alloc > >
-            : boost::true_type
-        {
-            typedef Traits trait_t;
-        };
-
-        template < class Char, class Traits, class Alloc>
-        struct extract_char_traits< Char, boost::container::basic_string< Char, Traits, Alloc > >
-            : boost::true_type
-        {
-            typedef Traits trait_t;
-        };
-
-#ifndef BOOST_NO_CXX17_HDR_STRING_VIEW
-        template < class Char, class Traits >
-        struct extract_char_traits< Char, std::basic_string_view< Char, Traits > >
-            : boost::true_type
-        {
-            typedef Traits trait_t;
-        };
-#endif
-        template < class Char, class Traits >
-        struct extract_char_traits< Char, boost::basic_string_view< Char, Traits > >
-            : boost::true_type
-        {
-            typedef Traits trait_t;
-        };
-    }
-
     namespace detail // array_to_pointer_decay<T>
     {
         template<class T>
@@ -466,11 +425,7 @@ namespace boost {
                 "Your compiler does not have full support for char32_t" );
 #endif
 
-            typedef typename boost::conditional<
-                boost::detail::extract_char_traits<char_type, Target>::value,
-                typename boost::detail::extract_char_traits<char_type, Target>,
-                typename boost::detail::extract_char_traits<char_type, no_cv_src>
-            >::type::trait_t traits;
+            typedef std::char_traits<char_type> traits;
 
             typedef boost::detail::lcast_src_length<no_cv_src> len_t;
         };

include/boost/lexical_cast/detail/converter_lexical_streams.hpp

@@ -264,15 +264,15 @@ namespace boost { namespace detail { namespace lcast {
             ), bool
         >::type;
 
-        template<class Alloc>
-        bool stream_in(lcast::exact<std::basic_string<CharT,Traits,Alloc>> x) noexcept {
+        template<class CharTraits, class Alloc>
+        bool stream_in(lcast::exact<std::basic_string<CharT,CharTraits,Alloc>> x) noexcept {
             start = x.payload.data();
             finish = start + x.payload.length();
             return true;
         }
 
-        template<class Alloc>
-        bool stream_in(lcast::exact<boost::container::basic_string<CharT,Traits,Alloc>> x) noexcept {
+        template<class CharTraits, class Alloc>
+        bool stream_in(lcast::exact<boost::container::basic_string<CharT,CharTraits,Alloc>> x) noexcept {
             start = x.payload.data();
             finish = start + x.payload.length();
             return true;
@@ -342,15 +342,15 @@ namespace boost { namespace detail { namespace lcast {
         }
 
 #ifndef BOOST_NO_CXX17_HDR_STRING_VIEW
-        template <class C>
+        template <class C, class CharTraits>
         enable_if_compatible_char_t<C>
-        stream_in(lcast::exact<std::basic_string_view<C, Traits>> x) noexcept {
+        stream_in(lcast::exact<std::basic_string_view<C, CharTraits>> x) noexcept {
             return shl_char_array_limited(reinterpret_cast<const CharT*>(x.payload.data()), x.payload.size());
         }
 #endif
-        template <class C>
+        template <class C, class CharTraits>
         enable_if_compatible_char_t<C>
-        stream_in(lcast::exact<boost::basic_string_view<C, Traits>> x) noexcept {
+        stream_in(lcast::exact<boost::basic_string_view<C, CharTraits>> x) noexcept {
             return shl_char_array_limited(reinterpret_cast<const CharT*>(x.payload.data()), x.payload.size());
         }
     };
@@ -648,13 +648,13 @@ namespace boost { namespace detail { namespace lcast {
 #if !defined(BOOST_NO_CXX11_CHAR32_T) && !defined(BOOST_NO_CXX11_UNICODE_LITERALS)
         bool stream_out(char32_t& output)                   { return shr_xchar(output); }
 #endif
-        template<class Alloc>
-        bool stream_out(std::basic_string<CharT,Traits,Alloc>& str) {
+        template<class CharTraits, class Alloc>
+        bool stream_out(std::basic_string<CharT,CharTraits,Alloc>& str) {
             str.assign(start, finish); return true;
         }
 
-        template<class Alloc>
-        bool stream_out(boost::container::basic_string<CharT,Traits,Alloc>& str) {
+        template<class CharTraits, class Alloc>
+        bool stream_out(boost::container::basic_string<CharT,CharTraits,Alloc>& str) {
             str.assign(start, finish); return true;
         }
 

test/lexical_cast_test.cpp

@@ -390,7 +390,6 @@ void test_no_whitespace_stripping()
     BOOST_TEST_THROWS(lexical_cast<int>("123 "), bad_lexical_cast);
 }
 
-#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
 void test_traits()
 {
     typedef std::basic_string<char, my_traits<char> > my_string;
@@ -399,6 +398,8 @@ void test_traits()
     BOOST_TEST(boost::lexical_cast<char>(s) == s[0]);
     BOOST_TEST(boost::lexical_cast<my_string>(s) == s);
     BOOST_TEST(boost::lexical_cast<my_string>(-1) == "-1");
+    BOOST_TEST(boost::lexical_cast<int>(my_string("42")) == 42);
+    BOOST_TEST(boost::lexical_cast<double>(my_string("1.0")) == 1.0);
 }
 
 void test_wtraits()
@@ -408,9 +409,9 @@ void test_wtraits()
     my_string const s(L"s");
     BOOST_TEST(boost::lexical_cast<wchar_t>(s) == s[0]);
     BOOST_TEST(boost::lexical_cast<my_string>(s) == s);
-    //BOOST_TEST(boost::lexical_cast<my_string>(-1) == L"-1");
-    // Commented out because gcc 3.3 doesn't support this:
-    // basic_ostream<wchar_t, my_traits<wchar_t> > o; o << -1;
+    BOOST_TEST(boost::lexical_cast<my_string>(-1) == L"-1");
+    BOOST_TEST(boost::lexical_cast<int>(my_string(L"42")) == 42);
+    BOOST_TEST(boost::lexical_cast<double>(my_string(L"1.0")) == 1.0);
 }
 
 void test_allocator()
@@ -457,8 +458,6 @@ void test_wallocator()
 #endif
 }
 
-#endif
-
 
 void test_char_types_conversions()
 {
@@ -578,12 +577,11 @@ int main()
 #endif
     test_bad_lexical_cast();
     test_no_whitespace_stripping();
-#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
+
     test_traits();
     test_wtraits();
     test_allocator();
     test_wallocator();
-#endif
 
     test_char_types_conversions();
     operators_overload_test();