1 files changed, 106 insertions, 0 deletions
diff --git a/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-null.hh b/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-null.hh
new file mode 100644
index 00000000000..91efee6443d
--- /dev/null
+++ b/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-null.hh
@@ -0,0 +1,106 @@
+/*
+ * 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-private.hh"
+
+
+/*
+ * Static pools
+ */
+
+/* Global nul-content Null pool.  Enlarge as necessary. */
+
+#define HB_NULL_POOL_SIZE 264
+
+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 <typename Type>
+static inline Type const & Null (void) {
+  static_assert (sizeof (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE.");
+  return *reinterpret_cast<Type const *> (_hb_NullPool);
+}
+#define Null(Type) Null<Type>()
+
+/* Specializaitons 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::min_size]; \
+template <> \
+/*static*/ inline const Namespace::Type& Null<Namespace::Type> (void) { \
+  return *reinterpret_cast<const Namespace::Type *> (_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::min_size]
+
+/* Specializaitons 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<Type> (void) { \
+  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 <typename Type>
+static inline Type& Crap (void) {
+  static_assert (sizeof (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE.");
+  Type *obj = reinterpret_cast<Type *> (_hb_CrapPool);
+  *obj = Null(Type);
+  return *obj;
+}
+#define Crap(Type) Crap<Type>()
+
+template <typename Type>
+struct CrapOrNull {
+  static inline Type & get (void) { return Crap(Type); }
+};
+template <typename Type>
+struct CrapOrNull<const Type> {
+  static inline Type const & get (void) { return Null(Type); }
+};
+#define CrapOrNull(Type) CrapOrNull<Type>::get ()
+
+
+#endif /* HB_NULL_HH */