diff options
Diffstat (limited to 'thirdparty/harfbuzz/src/hb-null.hh')
| -rw-r--r-- | thirdparty/harfbuzz/src/hb-null.hh | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/thirdparty/harfbuzz/src/hb-null.hh b/thirdparty/harfbuzz/src/hb-null.hh index d09f858cde..db38a4dfd2 100644 --- a/thirdparty/harfbuzz/src/hb-null.hh +++ b/thirdparty/harfbuzz/src/hb-null.hh @@ -39,8 +39,11 @@ #define HB_NULL_POOL_SIZE 384 -/* Use SFINAE to sniff whether T has min_size; in which case return T::null_size, - * otherwise return sizeof(T). */ +/* Use SFINAE to sniff whether T has min_size; in which case return the larger + * of sizeof(T) and T::null_size, otherwise return sizeof(T). + * + * The main purpose of this is to let structs communicate that they are not nullable, + * by defining min_size but *not* null_size. */ /* The hard way... * https://stackoverflow.com/questions/7776448/sfinae-tried-with-bool-gives-compiler-error-template-argument-tvalue-invol @@ -49,8 +52,9 @@ template <typename T, typename> struct _hb_null_size : hb_integral_constant<unsigned, sizeof (T)> {}; template <typename T> -struct _hb_null_size<T, hb_void_t<decltype (T::min_size)>> : hb_integral_constant<unsigned, T::null_size> {}; - +struct _hb_null_size<T, hb_void_t<decltype (T::min_size)>> + : hb_integral_constant<unsigned, + (sizeof (T) > T::null_size ? sizeof (T) : T::null_size)> {}; template <typename T> using hb_null_size = _hb_null_size<T, void>; #define hb_null_size(T) hb_null_size<T>::value @@ -68,6 +72,14 @@ template <typename T> using hb_static_size = _hb_static_size<T, void>; #define hb_static_size(T) hb_static_size<T>::value +template <typename T, typename> +struct _hb_min_size : hb_integral_constant<unsigned, sizeof (T)> {}; +template <typename T> +struct _hb_min_size<T, hb_void_t<decltype (T::min_size)>> : hb_integral_constant<unsigned, T::min_size> {}; +template <typename T> +using hb_min_size = _hb_min_size<T, void>; +#define hb_min_size(T) hb_min_size<T>::value + /* * Null() |