Fix mixed platform disagreement

Author: mborland

include/boost/decimal/cstdio.hpp

@@ -164,6 +164,12 @@ inline void make_uppercase(char* first, const char* last) noexcept
     }
 }
 
+// Cast of return value avoids warning when sizeof(std::ptrdiff_t) > sizeof(int) e.g. when not in 32-bit
+#if defined(__GNUC__) && defined(__i386__)
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wuseless-cast"
+#endif
+
 template <typename... T>
 inline auto snprintf_impl(char* buffer, const std::size_t buf_size, const char* format, const T... values) noexcept
     #ifndef BOOST_DECIMAL_HAS_CONCEPTS
@@ -247,9 +253,13 @@ inline auto snprintf_impl(char* buffer, const std::size_t buf_size, const char*
     }
 
     *buffer = '\0';
-    return (buffer - buffer_begin);
+    return static_cast<int>(buffer - buffer_begin);
 }
 
+#if defined(__GNUC__) && defined(__i386__)
+#  pragma GCC diagnostic pop
+#endif
+
 } // namespace detail
 
 template <typename... T>

include/boost/decimal/detail/locale_conversion.hpp

@@ -87,6 +87,12 @@ inline void convert_string_to_c_locale(char* buffer) noexcept
     convert_string_to_c_locale(buffer, std::locale());
 }
 
+// Cast of return value avoids warning when sizeof(std::ptrdiff_t) > sizeof(int) e.g. when not in 32-bit
+#if defined(__GNUC__) && defined(__i386__)
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wuseless-cast"
+#endif
+
 inline int convert_pointer_pair_to_local_locale(char* first, const char* last, const std::locale& loc) noexcept
 {
     const std::numpunct<char>& np = std::use_facet<std::numpunct<char>>(loc);
@@ -136,7 +142,7 @@ inline int convert_pointer_pair_to_local_locale(char* first, const char* last, c
     {
         if (int_digits > grouping_size)
         {
-            num_separators = (int_digits - 1) / grouping_size;
+            num_separators = static_cast<int>((int_digits - 1) / grouping_size);
         }
     }
 
@@ -186,6 +192,11 @@ inline int convert_pointer_pair_to_local_locale(char* first, const char* last, c
     return num_separators;
 }
 
+// Cast of return value avoids warning when sizeof(std::ptrdiff_t) > sizeof(int) e.g. when not in 32-bit
+#if defined(__GNUC__) && defined(__i386__)
+#  pragma GCC diagnostic pop
+#endif
+
 #if defined(__GNUC__) && __GNUC__ == 9
 #  pragma GCC diagnostic pop
 #elif defined(__clang__) && __clang_major__ == 12

include/boost/decimal/detail/to_chars_integer_impl.hpp

@@ -127,7 +127,7 @@ constexpr char* decompose32(std::uint32_t value, char* buffer) noexcept
 
     for (std::size_t i {}; i < 10; i += 2)
     {
-        boost::decimal::detail::memcpy(buffer + i, radix_table + static_cast<std::size_t>(y >> 57) * 2, 2);
+        boost::decimal::detail::memcpy(buffer + i, radix_table + (y >> 57) * 2, 2);
         y &= mask;
         y *= 100U;
     }