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this is allow custom allocator for obj-api structs/tables. (#4520)

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added "native_custom_alloc" attribute to tables/structs, eg.

table parent_table( native_custom_alloc:"custom_alloc_name" ) {
...
}

with a custom allocator defined as

template <typename T> class custom_alloc_name : public std::allocator<T> {
public:

 typedef T*       pointer;

 template <class U>
 struct rebind {
  typedef custom_alloc_name<U> other;
 };

 pointer allocate(const std::size_t n) {
      return ....;
 }

 void deallocate(T* ptr, std::size_t n) {
    ...
 }

 custom_alloc_name() throw() {}
 template <class U> custom_alloc_name(const custom_alloc_name<U>&) throw() {}
};
};
This commit is contained in:
rmawatson
2017-12-01 18:15:41 +01:00
committed by Wouter van Oortmerssen
parent ba08b0ec02
commit 53a897731e
7 changed files with 77 additions and 15 deletions
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20
src/idl_gen_cpp.cpp
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@@ -479,7 +479,11 @@ class CppGenerator : public BaseGenerator {
}
case BASE_TYPE_VECTOR: {
const auto type_name = GenTypeNative(type.VectorType(), true, field);
return "std::vector<" + type_name + ">";
if (type.struct_def && type.struct_def->attributes.Lookup("native_custom_alloc")) {
auto native_custom_alloc = type.struct_def->attributes.Lookup("native_custom_alloc");
return "std::vector<" + type_name + "," + native_custom_alloc->constant + "<" + type_name + ">>";
} else
return "std::vector<" + type_name + ">";
}
case BASE_TYPE_STRUCT: {
auto type_name = WrapInNameSpace(*type.struct_def);
@@ -1323,6 +1327,17 @@ class CppGenerator : public BaseGenerator {
code_ += " }";
}
void GenOperatorNewDelete(const StructDef & struct_def) {
if (auto native_custom_alloc = struct_def.attributes.Lookup("native_custom_alloc")) {
code_ += " inline void *operator new (std::size_t count) {";
code_ += " return " + native_custom_alloc->constant + "<{{NATIVE_NAME}}>().allocate(count / sizeof({{NATIVE_NAME}}));";
code_ += " }";
code_ += " inline void operator delete (void *ptr) {";
code_ += " return " + native_custom_alloc->constant + "<{{NATIVE_NAME}}>().deallocate(static_cast<{{NATIVE_NAME}}*>(ptr),1);";
code_ += " }";
}
}
void GenNativeTable(const StructDef &struct_def) {
const auto native_name = NativeName(Name(struct_def), &struct_def, parser_.opts);
code_.SetValue("STRUCT_NAME", Name(struct_def));
@@ -1336,6 +1351,7 @@ class CppGenerator : public BaseGenerator {
it != struct_def.fields.vec.end(); ++it) {
GenMember(**it);
}
GenOperatorNewDelete(struct_def);
GenDefaultConstructor(struct_def);
code_ += "};";
code_ += "";
@@ -2388,6 +2404,8 @@ class CppGenerator : public BaseGenerator {
code_ += " }";
}
}
code_.SetValue("NATIVE_NAME", Name(struct_def));
GenOperatorNewDelete(struct_def);
code_ += "};";
code_.SetValue("STRUCT_BYTE_SIZE", NumToString(struct_def.bytesize));