// WithdrawPct subtracts a percentage of the balance. It returns the
// quantity that has been deducted and an error or nil if the percentage
// is not in the range 0..100.
func (h *Resource) WithdrawPct(percentage float64) (us.Quantity, error) {
if percentage < 0 || percentage > 100 {
msg := fmt.Sprintf("percentage not in range 0..1")
return us.Quantity{}, errors.New(msg)
}
taken := us.MultFac(h.balance, percentage/100.0)
h.balance = us.Subtract(h.balance, taken)
return h.Convert(taken), nil
}
// Withdraw subtracts the given amount from the Resource.
// Return true for success, false for incompatible unit or out of bounds
func (h *Resource) Withdraw(q us.Quantity) bool {
if !us.AreCompatible(h.balance, q) {
return false
}
n := us.Subtract(h.balance, q)
if h.outOfBounds(n) {
return false
}
h.balance = n
return true
}