Function psbt_compute_fee

bitcoin/psbt.c:812–837

}

struct amount_sat psbt_compute_fee(const struct wally_psbt *psbt)
{
	struct amount_sat fee, input_amt;
	struct amount_asset asset;
	bool ok;

	fee = AMOUNT_SAT(0);
	for (size_t i = 0; i < psbt->num_inputs; i++) {
		input_amt = psbt_input_get_amount(psbt, i);
		ok = amount_sat_add(&fee, fee, input_amt);
		assert(ok);
	}

	for (size_t i = 0; i < psbt->num_outputs; i++) {
		asset = wally_tx_output_get_amount(&psbt->tx->outputs[i]);
		if (!amount_asset_is_main(&asset)
		    || elements_wtx_output_is_fee(psbt->tx, i))
			continue;

		ok = amount_sat_sub(&fee, fee, amount_asset_to_sat(&asset));
		if (!ok)
			return AMOUNT_SAT(0);
	}

	return fee;
}