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RoundStep method

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wildSeagull 2018-10-06 15:15:53 +03:00
parent cd690d0c9e
commit 810279ec16
2 changed files with 62 additions and 0 deletions
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24
decimal.go
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@ -777,6 +777,30 @@ func (d Decimal) Round(places int32) Decimal {
return ret
}
// RoundStep rounds the decimal to the nearest step value.
// Doesn't matter if step parameter is positive or negative,
// the result is the same.
// If lower is set to true, value will be rounded to the lower
// step value.
//
// Example:
//
// NewFromFloat(0.43).RoundStep(NewFromFloat(0.5), false).String() // output: "0.5"
// NewFromFloat(0.43).RoundStep(NewFromFloat(0.5), true).String() // output: "0"
// NewFromFloat(0.000355666).RoundStep(NewFromFloat(0.0005), false).String() // output: "0.0005"
// NewFromFloat(0.000355666).Round(NewFromFloat(0.0005), true).String() // output: "0"
// NewFromFloat(0.000355666).Round(NewFromFloat(0.0001), false).String() // output: "0.0004"
// NewFromFloat(0.000355666).Round(NewFromFloat(0.0001), true).String() // output: "0.0003"
//
func (d Decimal) RoundStep(step Decimal, lower bool) Decimal {
step = step.Abs()
if lower {
return d.Div(step).Floor().Mul(step)
}
return d.Div(step).Round(0).Mul(step)
}
// RoundBank rounds the decimal to places decimal places.
// If the final digit to round is equidistant from the nearest two integers the
// rounded value is taken as the even number

38
decimal_test.go
View file

@ -2395,6 +2395,44 @@ func TestAvg(t *testing.T) {
}
}
func TestRoundStep(t *testing.T) {
res := NewFromFloat(0.43).RoundStep(NewFromFloat(0.5), false)
exp := NewFromFloat(0.5)
if !res.Equal(exp) {
t.Errorf("Failed to round by step, expected %s got %s", exp.String(), res.String())
}
res = NewFromFloat(0.43).RoundStep(NewFromFloat(0.5), true)
exp = Zero
if !res.Equal(exp) {
t.Errorf("Failed to round by step, expected %s got %s", exp.String(), res.String())
}
res = NewFromFloat(0.000355666).RoundStep(NewFromFloat(0.0005), false)
exp = NewFromFloat(0.0005)
if !res.Equal(exp) {
t.Errorf("Failed to round by step, expected %s got %s", exp.String(), res.String())
}
res = NewFromFloat(0.000355666).RoundStep(NewFromFloat(0.0005), true)
exp = Zero
if !res.Equal(exp) {
t.Errorf("Failed to round by step, expected %s got %s", exp.String(), res.String())
}
res = NewFromFloat(0.000355666).RoundStep(NewFromFloat(0.0001), false)
exp = NewFromFloat(0.0004)
if !res.Equal(exp) {
t.Errorf("Failed to round by step, expected %s got %s", exp.String(), res.String())
}
res = NewFromFloat(0.000355666).RoundStep(NewFromFloat(0.0001), true)
exp = NewFromFloat(0.0003)
if !res.Equal(exp) {
t.Errorf("Failed to round by step, expected %s got %s", exp.String(), res.String())
}
}
func TestRoundBankAnomaly(t *testing.T) {
a := New(25, -1)
b := New(250, -2)