add ParseString constructor to util.Fixed8 (#79)

This commit is contained in:
Evgenii Stratonikov 2018-05-04 20:41:42 +03:00 committed by Anthony De Meulemeester
parent cff42de061
commit 0ca8865402
2 changed files with 50 additions and 1 deletions

View file

@ -2,10 +2,17 @@ package util
import (
"bytes"
"errors"
"strconv"
"strings"
)
const decimals = 100000000
const (
precision = 8
decimals = 100000000
)
var errInvalidString = errors.New("Fixed8 must satisfy following regex \\d+(\\.\\d{1,8})?")
// Fixed8 represents a fixed-point number with precision 10^-8.
type Fixed8 int64
@ -41,3 +48,23 @@ func (f Fixed8) Value() int64 {
func NewFixed8(val int) Fixed8 {
return Fixed8(decimals * val)
}
// Fixed8DecodeString
func Fixed8DecodeString(s string) (Fixed8, error) {
parts := strings.SplitN(s, ".", 2)
ip, err := strconv.Atoi(parts[0])
if err != nil {
return 0, errInvalidString
} else if len(parts) == 1 {
return NewFixed8(ip), nil
}
fp, err := strconv.Atoi(parts[1])
if err != nil || fp >= decimals {
return 0, errInvalidString
}
for i := len(parts[1]); i < precision; i++ {
fp *= 10
}
return Fixed8(ip*decimals + fp), nil
}

View file

@ -14,3 +14,25 @@ func TestNewFixed8(t *testing.T) {
assert.Equal(t, int64(val), NewFixed8(val).Value())
}
}
func TestFixed8DecodeString(t *testing.T) {
// Fixed8DecodeString works correctly with integers
ivalues := []string{"9000", "100000000", "5", "10945"}
for _, val:= range ivalues {
n, err := Fixed8DecodeString(val)
assert.Nil(t, err)
assert.Equal(t, val, n.String())
}
// Fixed8DecodeString parses number with maximal precision
val := "123456789.12345678"
n, err := Fixed8DecodeString(val)
assert.Nil(t, err)
assert.Equal(t, Fixed8(12345678912345678), n)
// Fixed8DecodeString parses number with non-maximal precision
val = "901.2341"
n, err = Fixed8DecodeString(val)
assert.Nil(t, err)
assert.Equal(t, Fixed8(90123410000), n)
}