[HB] Add OffsetTo template.
diff --git a/src/hb-ot-layout-open-private.h b/src/hb-ot-layout-open-private.h
index 7f0f54d..0c648ef 100644
--- a/src/hb-ot-layout-open-private.h
+++ b/src/hb-ot-layout-open-private.h
@@ -242,11 +242,6 @@
if (HB_UNLIKELY (!Name)) return Null(Type); \
return *(const Type*)((const char*)this + Name); \
}
-#define DEFINE_GET_HAS_ACCESSOR(Type, name, Name) \
- DEFINE_GET_ACCESSOR (Type, name, Name); \
- inline bool has_##name (void) const { \
- return Name != 0; \
- }
@@ -340,6 +335,21 @@
/* Offset to a table, same as uint16 (length = 16 bits), Null offset = 0x0000 */
DEFINE_INT_TYPE_STRUCT (Offset, u, 16);
+/* Template subclass of Offset that does the dereferencing. Use: (this+memberName) */
+template <typename Type>
+struct OffsetTo : Offset {
+ inline const Type& operator() (const void *base) const {
+ unsigned int offset = *this;
+ if (HB_UNLIKELY (!offset)) return Null(Type);
+ return * (const Type *) ((const char *) base + offset);
+ }
+};
+
+template <typename Base, typename Type>
+inline const Type& operator + (const Base &base, OffsetTo<Type> offset) {
+ return offset(base);
+}
+
/* CheckSum */
struct CheckSum : ULONG {
@@ -572,9 +582,7 @@
return defaultLangSys != 0;
}
inline const LangSys& get_default_lang_sys (void) const {
- if (HB_UNLIKELY (!defaultLangSys))
- return Null(LangSys);
- return *(LangSys*)((const char*)this + defaultLangSys);
+ return this+defaultLangSys;
}
private:
@@ -582,7 +590,8 @@
DEFINE_RECORD_ARRAY_TYPE (LangSys, langSysRecord, langSysCount);
private:
- Offset defaultLangSys; /* Offset to DefaultLangSys table--from
+ OffsetTo<LangSys>
+ defaultLangSys; /* Offset to DefaultLangSys table--from
* beginning of Script table--may be Null */
USHORT langSysCount; /* Number of LangSysRecords for this script--
* excluding the DefaultLangSys */
