fee.gno

 1package otc
 2
 3const bpsDenominator = 10000
 4
 5// feeOf is bps of amount, rounded down (F1). Split so that a large amount
 6// cannot overflow on the multiplication: bps is at most feeCapBps, so both
 7// terms stay far below int64 max.
 8func feeOf(amount, bps int64) int64 {
 9	if amount <= 0 || bps <= 0 {
10		return 0
11	}
12	return amount/bpsDenominator*bps + amount%bpsDenominator*bps/bpsDenominator
13}
14
15// feeFor picks the fee a new offer on tokenKey is created with (F4, F6).
16func feeFor(tokenKey string) int64 {
17	if gnomicFeeOn && tokenKey == gnomicKey {
18		return gnomicFee
19	}
20	return feeBps
21}
22
23// addSat adds two non-negative totals without wrapping (S5). The totals are
24// statistics, not money: one that stops at the ceiling is better than one
25// that turns negative.
26func addSat(a, b int64) int64 {
27	if b > 0 && a > maxInt64-b {
28		return maxInt64
29	}
30	return a + b
31}
32
33const maxInt64 = int64(9223372036854775807)