Function amount_msat_mul_div

common/amount.c:608–620

}

static bool amount_msat_mul_div(struct amount_msat *res,
				struct amount_msat msat, u64 mul, u64 div)
{
	/* We avoid overflow in the operation (a/b)*x noticing that we can
	 * decompose x = q_x * b + r_x, where q_x = floor(x/b) and
	 * r_x = x mod b, then: x*(a/b) = a*q_x + a*r_x/b, which does not
	 * overflow if a*b does not. */
	if (mul_overflows_u64(mul, div))
		return false;
	u64 x = msat.millisatoshis;
	res->millisatoshis = mul * (x / div) + (mul * (x % div)) / div;
	return true;
}

bool amount_msat_fee(struct amount_msat *fee,
		     struct amount_msat amt,