template <class STATE>
void Initialize(STATE &state) {
	state.count = 0;
	state.sum = 0;
}

template <class INPUT_TYPE, class STATE, class OP>
void Operation(STATE &state, const INPUT_TYPE &input, AggregateUnaryInput &) {
	state.sum += input;
	state.count++;
}

template <class STATE, class OP>
void Combine(const STATE &source, STATE &target, AggregateInputData &) {
	target.count += source.count;
	target.sum += source.sum;
}

template <class T, class STATE>
void Finalize(STATE &state, T &target, AggregateFinalizeData &finalize_data) {
	if (state.count == 0) {
		finalize_data.ReturnNull();
	} else {
		target = state.sum / state.count;
	}
}

template <class STATE>
void Initialize(STATE *state) {
	state->count = 0;
	state->sum = 0;
}

template <class INPUT_TYPE, class STATE, class OP>
void Operation(STATE *state, AggregateInputData &, const INPUT_TYPE *input, ValidityMask &mask, idx_t idx) {
	state->sum += input[idx];
	state->count++;
}

template <class STATE, class OP>
void Combine(const STATE &source, STATE *target, AggregateInputData &) {
	target->count += source.count;
	target->sum += source.sum;
}

template <class T, class STATE>
void Finalize(Vector &result, AggregateInputData &, STATE *state, T *target, ValidityMask &mask, idx_t idx) {
	if (state->count == 0) {
		mask.SetInvalid(idx);
	} else {
		target[idx] = state->sum / state->count;
	}
}