Merge pull request #813 from cppalliance/803

Remove `sprintf` and fix conceptual requirements for <cstdio>

Author: mborland

doc/decimal/cstdio.adoc

@@ -20,9 +20,6 @@ namespace decimal {
 template <typename... Dec>
 int snprintf(char* buffer, std::size_t buf_size, const char* format, Dec... value) noexcept;
 
-template <typename... Dec>
-int sprintf(char* buffer, const char* format, Dec... value) noexcept;
-
 template <typename... Dec>
 int fprintf(std::FILE* buffer, const char* format, Dec... values) noexcept;
 
@@ -33,8 +30,6 @@ int printf(const char* format, Dec... values) noexcept;
 } //namespace boost
 ----
 
-WARNING: In the interest of safety `sprintf` simply calls `snprintf` with buf_size equal to sizeof(buffer).
-
 === Type Modifiers
 
 The type modifiers to be used are:

include/boost/decimal/cstdio.hpp

@@ -157,9 +157,9 @@ inline void make_uppercase(char* first, const char* last) noexcept
 template <typename... T>
 inline auto snprintf_impl(char* buffer, std::size_t buf_size, const char* format, T... values) noexcept
     #ifndef BOOST_DECIMAL_HAS_CONCEPTS
-    -> std::enable_if_t<detail::is_decimal_floating_point_v<std::common_type_t<T...>>, int>
+    -> std::enable_if_t<detail::conjunction_v<detail::is_decimal_floating_point<T>...>, int>
     #else
-    -> int requires detail::is_decimal_floating_point_v<std::common_type_t<T...>>
+    -> int requires detail::conjunction_v<detail::is_decimal_floating_point<T>...>
     #endif
 {
     if (buffer == nullptr || format == nullptr)
@@ -246,31 +246,20 @@ inline auto snprintf_impl(char* buffer, std::size_t buf_size, const char* format
 template <typename... T>
 inline auto snprintf(char* buffer, std::size_t buf_size, const char* format, T... values) noexcept
     #ifndef BOOST_DECIMAL_HAS_CONCEPTS
-    -> std::enable_if_t<detail::is_decimal_floating_point_v<std::common_type_t<T...>>, int>
+    -> std::enable_if_t<detail::conjunction_v<detail::is_decimal_floating_point<T>...>, int>
     #else
-    -> int requires detail::is_decimal_floating_point_v<std::common_type_t<T...>>
+    -> int requires detail::conjunction_v<detail::is_decimal_floating_point<T>...>
     #endif
 {
     return detail::snprintf_impl(buffer, buf_size, format, values...);
 }
 
-template <typename... T>
-inline auto sprintf(char* buffer, const char* format, T... values) noexcept
-    #ifndef BOOST_DECIMAL_HAS_CONCEPTS
-    -> std::enable_if_t<detail::is_decimal_floating_point_v<std::common_type_t<T...>>, int>
-    #else
-    -> int requires detail::is_decimal_floating_point_v<std::common_type_t<T...>>
-    #endif
-{
-    return detail::snprintf_impl(buffer, sizeof(buffer), format, values...);
-}
-
 template <typename... T>
 inline auto fprintf(std::FILE* buffer, const char* format, T... values) noexcept
-#ifndef BOOST_DECIMAL_HAS_CONCEPTS
-    -> std::enable_if_t<detail::is_decimal_floating_point_v<std::common_type_t<T...>>, int>
+    #ifndef BOOST_DECIMAL_HAS_CONCEPTS
+    -> std::enable_if_t<detail::conjunction_v<detail::is_decimal_floating_point<T>...>, int>
     #else
-    -> int requires detail::is_decimal_floating_point_v<std::common_type_t<T...>>
+    -> int requires detail::conjunction_v<detail::is_decimal_floating_point<T>...>
     #endif
 {
     if (format == nullptr)
@@ -319,9 +308,9 @@ inline auto fprintf(std::FILE* buffer, const char* format, T... values) noexcept
 template <typename... T>
 inline auto printf(const char* format, T... values) noexcept
     #ifndef BOOST_DECIMAL_HAS_CONCEPTS
-    -> std::enable_if_t<detail::is_decimal_floating_point_v<std::common_type_t<T...>>, int>
+    -> std::enable_if_t<detail::conjunction_v<detail::is_decimal_floating_point<T>...>, int>
     #else
-    -> int requires detail::is_decimal_floating_point_v<std::common_type_t<T...>>
+    -> int requires detail::conjunction_v<detail::is_decimal_floating_point<T>...>
     #endif
 {
     return fprintf(stdout, format, values...);

include/boost/decimal/detail/type_traits.hpp

@@ -156,6 +156,19 @@ constexpr bool is_decimal_floating_point<T>::value;
 template <typename T>
 constexpr bool is_decimal_floating_point_v = is_decimal_floating_point<T>::value;
 
+template <typename...>
+struct conjunction : std::true_type {};
+
+template <typename B1>
+struct conjunction<B1> : B1 {};
+
+template <typename B1, typename... Bn>
+struct conjunction<B1, Bn...>
+        : std::conditional_t<bool(B1::value), conjunction<Bn...>, B1> {};
+
+template <typename... B>
+BOOST_DECIMAL_CONSTEXPR_VARIABLE bool conjunction_v = conjunction<B...>::value;
+
 } // namespace detail
 } // namespace decimal
 } // namespace boost