namespace factor
{

template<typename Visitor> struct code_block_visitor {
	factor_vm *parent;
	Visitor visitor;

	explicit code_block_visitor(factor_vm *parent_, Visitor visitor_) :
		parent(parent_), visitor(visitor_) {}

	void visit_object_code_block(object *obj);
	void visit_embedded_code_pointers(code_block *compiled);
	void visit_context_code_blocks();
	void visit_callback_code_blocks();
};

template<typename Visitor>
struct call_frame_code_block_visitor {
	factor_vm *parent;
	Visitor visitor;

	explicit call_frame_code_block_visitor(factor_vm *parent_, Visitor visitor_) :
		parent(parent_), visitor(visitor_) {}

	void operator()(stack_frame *frame)
	{
		cell offset = (cell)FRAME_RETURN_ADDRESS(frame,parent) - (cell)frame->xt;

		code_block *new_block = visitor(parent->frame_code(frame));
		frame->xt = new_block->xt();

		FRAME_RETURN_ADDRESS(frame,parent) = (void *)((cell)frame->xt + offset);
	}
};

template<typename Visitor>
void code_block_visitor<Visitor>::visit_object_code_block(object *obj)
{
	switch(obj->type())
	{
	case WORD_TYPE:
		{
			word *w = (word *)obj;
			if(w->code)
				w->code = visitor(w->code);
			if(w->profiling)
				w->profiling = visitor(w->profiling);

			parent->update_word_xt(w);
			break;
		}
	case QUOTATION_TYPE:
		{
			quotation *q = (quotation *)obj;
			if(q->code)
				parent->set_quot_xt(q,visitor(q->code));
			break;
		}
	case CALLSTACK_TYPE:
		{
			callstack *stack = (callstack *)obj;
			call_frame_code_block_visitor<Visitor> call_frame_visitor(parent,visitor);
			parent->iterate_callstack_object(stack,call_frame_visitor);
			break;
		}
	}
}

template<typename Visitor>
struct embedded_code_pointers_visitor {
	Visitor visitor;

	explicit embedded_code_pointers_visitor(Visitor visitor_) : visitor(visitor_) {}

	void operator()(relocation_entry rel, cell index, code_block *compiled)
	{
		relocation_type type = rel.rel_type();
		if(type == RT_XT || type == RT_XT_PIC || type == RT_XT_PIC_TAIL)
		{
			instruction_operand op(rel.rel_class(),rel.rel_offset() + (cell)compiled->xt());
			cell literal = op.load_value();
			code_block *compiled = ((code_block *)literal - 1);
			compiled = visitor(compiled);
			literal = (cell)compiled->xt();
			op.store_value(literal);
		}
	}
};

template<typename Visitor>
void code_block_visitor<Visitor>::visit_embedded_code_pointers(code_block *compiled)
{
	if(!parent->code->needs_fixup_p(compiled))
	{
		embedded_code_pointers_visitor<Visitor> visitor(this->visitor);
		parent->iterate_relocations(compiled,visitor);
	}
}

template<typename Visitor>
void code_block_visitor<Visitor>::visit_context_code_blocks()
{
	call_frame_code_block_visitor<Visitor> call_frame_visitor(parent,visitor);
	parent->iterate_active_frames(call_frame_visitor);
}

template<typename Visitor>
struct callback_code_block_visitor {
	callback_heap *callbacks;
	Visitor visitor;

	explicit callback_code_block_visitor(callback_heap *callbacks_, Visitor visitor_) :
		callbacks(callbacks_), visitor(visitor_) {}

	void operator()(callback *stub)
	{
		stub->compiled = visitor(stub->compiled);
		callbacks->update(stub);
	}
};

template<typename Visitor>
void code_block_visitor<Visitor>::visit_callback_code_blocks()
{
	callback_code_block_visitor<Visitor> callback_visitor(parent->callbacks,visitor);
	parent->callbacks->iterate(callback_visitor);
}

}