95 lines
2.6 KiB
C++
95 lines
2.6 KiB
C++
// Get Custom Wrapper From Object
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template <typename Data>
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Data *custom_get(typename Data::__Self *self) {
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return (Data *) (self + 1);
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}
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// Duplicate VTable
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template <typename T>
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T *custom_dup_vtable(const T *vtable) {
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// Get Size
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constexpr size_t rtti_size = sizeof(void *);
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const unsigned char *const real_vtable = ((const unsigned char *) vtable) - rtti_size;
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constexpr size_t real_vtable_size = sizeof(T) + rtti_size;
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// Allocate
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unsigned char *const new_vtable = (unsigned char *) ::operator new(real_vtable_size);
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T *ret = (T *) (new_vtable + rtti_size);
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new (ret) T;
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// Copy
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memcpy(new_vtable, real_vtable, real_vtable_size);
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// Return
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return ret;
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}
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// Base
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template <typename A, typename B>
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struct __CustomBase {
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// Properties
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typedef A __Self;
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typedef B __VTable;
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__Self *const self;
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// Prevent Copying
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__PREVENT_COPY(__CustomBase);
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#define get_self(ptr) (((__Self *) ptr) - 1)
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#ifdef {{ BUILDING_SYMBOLS_GUARD }}
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// Constructor
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__CustomBase():
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self(get_self(this)) {}
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#else
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// Prevent Construction
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__PREVENT_JUST_CONSTRUCTION(__CustomBase);
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#endif
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// Destructor
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virtual ~__CustomBase() = default;
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// Allocation
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void *operator new(const size_t count) {
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const size_t size = sizeof(__Self) + count;
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__Self *out = (__Self *) ::operator new(size);
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return (void *) custom_get<__CustomBase>(out);
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}
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void *operator new[](size_t) = delete;
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// Deallocation
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void operator delete(__CustomBase *ptr, std::destroying_delete_t) {
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if (ptr) {
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__Self *self = ptr->self;
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// This Calls The Actual Destructor
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self->vtable->destructor_deleting(self);
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}
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}
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void operator delete(void *ptr) {
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if (ptr) {
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// Issue During Construction, Just Free Memory
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::operator delete(get_self(ptr));
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}
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}
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#undef get_self
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void operator delete[](void *) = delete;
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protected:
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// VTable
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virtual void __patch_vtable(__VTable *vtable) {
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// Patch Destructors
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#define patch(type) \
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vtable->type = [](__Self *self) { \
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custom_get<__CustomBase>(self)->~__CustomBase(); \
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return __VTable::base->type(self); \
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}
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patch(destructor_complete);
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patch(destructor_deleting);
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#undef patch
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}
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void __set_vtable() {
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static __VTable *vtable = nullptr;
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if (!vtable) {
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// Create VTable
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vtable = custom_dup_vtable(__VTable::base);
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__patch_vtable(vtable);
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}
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this->self->vtable = vtable;
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}
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}; |