50 lines
1.1 KiB
Go
50 lines
1.1 KiB
Go
package main
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import (
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"math"
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pb "frontend/genproto"
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)
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// TODO(ahmetb): any logic below is flawed because I just realized we have no
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// way of representing amounts like 17.07 because Fractional cannot store 07.
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func multMoney(m pb.MoneyAmount, n uint32) pb.MoneyAmount {
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out := m
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for n > 1 {
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out = sum(out, m)
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n--
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}
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return out
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}
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func sum(m1, m2 pb.MoneyAmount) pb.MoneyAmount {
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// TODO(ahmetb) this is copied from ./checkoutservice/money.go, find a
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// better mult function.
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f1, f2 := float64(m1.Fractional), float64(m2.Fractional)
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lg1 := math.Max(1, math.Ceil(math.Log10(f1)))
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if f1 == math.Pow(10, lg1) {
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lg1++
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}
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lg2 := math.Max(1, math.Ceil(math.Log10(f2)))
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if f2 == math.Pow(10, lg2) {
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lg2++
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}
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lgMax := math.Max(lg1, lg2)
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dSum := m1.Decimal + m2.Decimal
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o1 := f1 * math.Pow(10, lgMax-lg1)
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o2 := f2 * math.Pow(10, lgMax-lg2)
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fSum := o1 + o2
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if fSum >= math.Pow(10, lgMax) {
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fSum -= math.Pow(10, lgMax)
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dSum++
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}
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for int(fSum)%10 == 0 && fSum != 0 {
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fSum = float64(int(fSum) / 10)
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}
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return pb.MoneyAmount{
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Decimal: dSum,
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Fractional: uint32(fSum)}
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}
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