Use class templates for Null objects
This allows partial-instantiating custom Null object for template Lookup<T>. Before, this had to be handcoded per instantiation. Apparently I missed adding one for AAT::ankr.lookupTable, so it was getting the wrong (generic) null for Lookup object, which is wrong and unsafe. Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=944346
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@ -418,15 +418,11 @@ struct Lookup
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} /* Close namespace. */
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/* Ugly hand-coded null objects for template Lookup<> :(. */
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extern HB_INTERNAL const unsigned char _hb_Null_AAT_Lookup[2];
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template <>
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/*static*/ inline const AAT::Lookup<OT::HBUINT16>& Null<AAT::Lookup<OT::HBUINT16> > ()
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{ return *reinterpret_cast<const AAT::Lookup<OT::HBUINT16> *> (_hb_Null_AAT_Lookup); }
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template <>
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/*static*/ inline const AAT::Lookup<OT::HBUINT32>& Null<AAT::Lookup<OT::HBUINT32> > ()
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{ return *reinterpret_cast<const AAT::Lookup<OT::HBUINT32> *> (_hb_Null_AAT_Lookup); }
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template <>
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/*static*/ inline const AAT::Lookup<OT::Offset<OT::HBUINT16, false> >& Null<AAT::Lookup<OT::Offset<OT::HBUINT16, false> > > ()
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{ return *reinterpret_cast<const AAT::Lookup<OT::Offset<OT::HBUINT16, false> > *> (_hb_Null_AAT_Lookup); }
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template <typename T>
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struct Null<AAT::Lookup<T> > {
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static AAT::Lookup<T> const & get_null ()
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{ return *reinterpret_cast<const AAT::Lookup<T> *> (_hb_Null_AAT_Lookup); }
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};
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namespace AAT {
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enum { DELETED_GLYPH = 0xFFFF };
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@ -105,15 +105,18 @@ hb_vector_size_impl_t const _hb_NullPool[(HB_NULL_POOL_SIZE + sizeof (hb_vector_
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/* Generic nul-content Null objects. */
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template <typename Type>
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static inline Type const & Null () {
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static_assert (hb_null_size (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE.");
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return *reinterpret_cast<Type const *> (_hb_NullPool);
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}
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struct Null {
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static Type const & get_null ()
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{
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static_assert (hb_null_size (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE.");
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return *reinterpret_cast<Type const *> (_hb_NullPool);
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}
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};
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template <typename QType>
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struct NullHelper
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{
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typedef typename hb_remove_const (typename hb_remove_reference (QType)) Type;
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static const Type & get_null () { return Null<Type> (); }
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static const Type & get_null () { return Null<Type>::get_null (); }
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};
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#define Null(Type) NullHelper<Type>::get_null ()
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@ -122,9 +125,11 @@ struct NullHelper
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} /* Close namespace. */ \
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extern HB_INTERNAL const unsigned char _hb_Null_##Namespace##_##Type[Namespace::Type::null_size]; \
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template <> \
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/*static*/ inline const Namespace::Type& Null<Namespace::Type> () { \
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return *reinterpret_cast<const Namespace::Type *> (_hb_Null_##Namespace##_##Type); \
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} \
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struct Null<Namespace::Type> { \
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static Namespace::Type const & get_null () { \
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return *reinterpret_cast<const Namespace::Type *> (_hb_Null_##Namespace##_##Type); \
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} \
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}; \
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namespace Namespace { \
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static_assert (true, "Just so we take semicolon after.")
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#define DEFINE_NULL_NAMESPACE_BYTES(Namespace, Type) \
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@ -134,10 +139,12 @@ struct NullHelper
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#define DECLARE_NULL_INSTANCE(Type) \
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extern HB_INTERNAL const Type _hb_Null_##Type; \
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template <> \
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/*static*/ inline const Type& Null<Type> () { \
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return _hb_Null_##Type; \
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} \
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static_assert (true, "Just so we take semicolon after.")
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struct Null<Type> { \
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static Type const & get_null () { \
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return _hb_Null_##Type; \
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} \
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}; \
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static_assert (true, "Just so we take semicolon after.")
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#define DEFINE_NULL_INSTANCE(Type) \
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const Type _hb_Null_##Type
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