--- /dev/null 2019-02-21 13:14:21.200397537 -0800 +++ new/src/java.desktop/share/native/libfontmanager/harfbuzz/hb-null.hh 2019-02-28 12:04:38.770502304 -0800 @@ -0,0 +1,204 @@ +/* + * Copyright © 2018 Google, Inc. + * + * This is part of HarfBuzz, a text shaping library. + * + * Permission is hereby granted, without written agreement and without + * license or royalty fees, to use, copy, modify, and distribute this + * software and its documentation for any purpose, provided that the + * above copyright notice and the following two paragraphs appear in + * all copies of this software. + * + * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR + * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES + * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN + * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH + * DAMAGE. + * + * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, + * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND + * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS + * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO + * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + * + * Google Author(s): Behdad Esfahbod + */ + +#ifndef HB_NULL_HH +#define HB_NULL_HH + +#include "hb.hh" + + +/* + * Static pools + */ + +/* Global nul-content Null pool. Enlarge as necessary. */ + +#define HB_NULL_POOL_SIZE 9880 + +/* Use SFINAE to sniff whether T has min_size; in which case return T::null_size, + * otherwise return sizeof(T). */ + +/* The hard way... + * https://stackoverflow.com/questions/7776448/sfinae-tried-with-bool-gives-compiler-error-template-argument-tvalue-invol + */ + +template struct _hb_bool_type {}; + +template +struct _hb_null_size +{ enum { value = sizeof (T) }; }; +template +struct _hb_null_size > +{ enum { value = T::null_size }; }; + +template +struct hb_null_size +{ enum { value = _hb_null_size >::value }; }; +#define hb_null_size(T) hb_null_size::value + +/* These doesn't belong here, but since is copy/paste from above, put it here. */ + +/* hb_static_size (T) + * Returns T::static_size if T::min_size is defined, or sizeof (T) otherwise. */ + +template +struct _hb_static_size +{ enum { value = sizeof (T) }; }; +template +struct _hb_static_size > +{ enum { value = T::static_size }; }; + +template +struct hb_static_size +{ enum { value = _hb_static_size >::value }; }; +#define hb_static_size(T) hb_static_size::value + + +/* hb_assign (obj, value) + * Calls obj.set (value) if obj.min_size is defined and value has different type + * from obj, or obj = v otherwise. */ + +template +struct _hb_assign +{ static inline void value (T &o, const V v) { o = v; } }; +template +struct _hb_assign > +{ static inline void value (T &o, const V v) { o.set (v); } }; +template +struct _hb_assign > +{ static inline void value (T &o, const T v) { o = v; } }; + +template +static inline void hb_assign (T &o, const V v) +{ _hb_assign >::value (o, v); } + + +/* + * Null() + */ + +extern HB_INTERNAL +hb_vector_size_impl_t const _hb_NullPool[(HB_NULL_POOL_SIZE + sizeof (hb_vector_size_impl_t) - 1) / sizeof (hb_vector_size_impl_t)]; + +/* Generic nul-content Null objects. */ +template +static inline Type const & Null () { + static_assert (hb_null_size (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE."); + return *reinterpret_cast (_hb_NullPool); +} +template +struct NullHelper +{ + typedef typename hb_remove_const (typename hb_remove_reference (QType)) Type; + static const Type & get_null () { return Null (); } +}; +#define Null(Type) NullHelper::get_null () + +/* Specializations for arbitrary-content Null objects expressed in bytes. */ +#define DECLARE_NULL_NAMESPACE_BYTES(Namespace, Type) \ + } /* Close namespace. */ \ + extern HB_INTERNAL const unsigned char _hb_Null_##Namespace##_##Type[Namespace::Type::null_size]; \ + template <> \ + /*static*/ inline const Namespace::Type& Null () { \ + return *reinterpret_cast (_hb_Null_##Namespace##_##Type); \ + } \ + namespace Namespace { \ + static_assert (true, "Just so we take semicolon after.") +#define DEFINE_NULL_NAMESPACE_BYTES(Namespace, Type) \ + const unsigned char _hb_Null_##Namespace##_##Type[Namespace::Type::null_size] + +/* Specializations for arbitrary-content Null objects expressed as struct initializer. */ +#define DECLARE_NULL_INSTANCE(Type) \ + extern HB_INTERNAL const Type _hb_Null_##Type; \ + template <> \ + /*static*/ inline const Type& Null () { \ + return _hb_Null_##Type; \ + } \ +static_assert (true, "Just so we take semicolon after.") +#define DEFINE_NULL_INSTANCE(Type) \ + const Type _hb_Null_##Type + +/* Global writable pool. Enlarge as necessary. */ + +/* To be fully correct, CrapPool must be thread_local. However, we do not rely on CrapPool + * for correct operation. It only exist to catch and divert program logic bugs instead of + * causing bad memory access. So, races there are not actually introducing incorrectness + * in the code. Has ~12kb binary size overhead to have it, also clang build fails with it. */ +extern HB_INTERNAL +/*thread_local*/ hb_vector_size_impl_t _hb_CrapPool[(HB_NULL_POOL_SIZE + sizeof (hb_vector_size_impl_t) - 1) / sizeof (hb_vector_size_impl_t)]; + +/* CRAP pool: Common Region for Access Protection. */ +template +static inline Type& Crap () { + static_assert (hb_null_size (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE."); + Type *obj = reinterpret_cast (_hb_CrapPool); + memcpy (obj, &Null(Type), sizeof (*obj)); + return *obj; +} +template +struct CrapHelper +{ + typedef typename hb_remove_const (typename hb_remove_reference (QType)) Type; + static Type & get_crap () { return Crap (); } +}; +#define Crap(Type) CrapHelper::get_crap () + +template +struct CrapOrNullHelper { + static Type & get () { return Crap(Type); } +}; +template +struct CrapOrNullHelper { + static const Type & get () { return Null(Type); } +}; +#define CrapOrNull(Type) CrapOrNullHelper::get () + + +/* + * hb_nonnull_ptr_t + */ + +template +struct hb_nonnull_ptr_t +{ + typedef typename hb_remove_pointer (P) T; + + hb_nonnull_ptr_t (T *v_ = nullptr) : v (v_) {} + T * operator = (T *v_) { return v = v_; } + T * operator -> () const { return get (); } + T & operator * () const { return *get (); } + T ** operator & () const { return &v; } + /* Only auto-cast to const types. */ + template operator const C * () const { return get (); } + operator const char * () const { return (const char *) get (); } + T * get () const { return v ? v : const_cast (&Null(T)); } + T * get_raw () const { return v; } + + T *v; +}; + + +#endif /* HB_NULL_HH */