added formatting helpers for balance (zcn,mzcn,uzcn,sas) #10

core/common/misc.go

@@ -2,32 +2,13 @@ package common
 
 import (
 	"fmt"
+	"regexp"
 	"strconv"
 	"strings"
 
 	"github.com/0chain/errors"
 )
 
-const tokenUnit = 10000000000.0
-
-// Balance represents an amount of tokens.
-type Balance int64
-
-// ToToken converts the Balance to ZCN tokens.
-func (b Balance) ToToken() float64 {
-	return float64(b) / tokenUnit
-}
-
-// ToBalance converts ZCN tokens to Balance.
-func ToBalance(tok float64) Balance {
-	return Balance(tok * tokenUnit)
-}
-
-// String implements fmt.Stringer interface.
-func (b Balance) String() string {
-	return strconv.FormatFloat(b.ToToken(), 'f', -1, 64)
-}
-
 // A Key represents an identifier. It can be a pool ID, client ID, smart
 // contract address, etc.
 type Key string
@@ -95,3 +76,134 @@ func (wp *WhoPays) Parse(val string) (err error) {
 	}
 	return
 }
+
+/* Balance */
+
+// minimum token unit (sas)
+const tokenUnit = 1e10
+
+// reParseToken is a regexp to parse string representation of token
+var reParseToken = regexp.MustCompile(`^((?:\d*\.)?\d+)\s+(SAS|sas|uZCN|uzcn|mZCN|mzcn|ZCN|zcn)$`)
+
+// Balance represents 0chain native token
+type Balance int64
+
+func (b Balance) ToToken() float64 {
+	return float64(b) / tokenUnit
+}
+
+// String implements fmt.Stringer interface.
+func (b Balance) String() string {
+	return b.AutoFormat()
+}
+
+func (b Balance) Format(unit BalanceUnit) string {
+	v := float64(b)
+	switch unit {
+	case SAS:
+		return fmt.Sprintf("%d %v", b, unit)
+	case UZCN:
+		v /= 1e4
+	case MZCN:
+		v /= 1e7
+	case ZCN:
+		v /= 1e10
+	}
+	return fmt.Sprintf("%.3f %v", v, unit)
+}
+
+func (b Balance) AutoFormat() string {
+	switch {
+	case b/1e10 > 0:
+		return b.Format(ZCN)
+	case b/1e7 > 0:
+		return b.Format(MZCN)
+	case b/1e4 > 0:
+		return b.Format(UZCN)
+	}
+	return b.Format(SAS)
+}
+
+// ToBalance converts ZCN tokens to Balance.
+func ToBalance(token float64) Balance {
+	return Balance(token * tokenUnit)
+}
+
+func FormatBalance(b Balance, unit BalanceUnit) string {
+	return b.Format(unit)
+}
+
+func AutoFormatBalance(b Balance) string {
+	return b.AutoFormat()
+}
+
+func ParseBalance(str string) (Balance, error) {
+
+	matches := reParseToken.FindAllStringSubmatch(str, -1)
+
+	if len(matches) != 1 || len(matches[0]) != 3 {
+		return 0, fmt.Errorf("invalid input: %s", str)
+	}
+
+	b, err := strconv.ParseFloat(matches[0][1], 64)
+	if err != nil {
+		return 0, err
+	}
+
+	var unit BalanceUnit
+
+	err = unit.Parse(matches[0][2])
+	if err != nil {
+		return 0, err
+	}
+
+	switch unit {
+	case UZCN:
+		b *= 1e4
+	case MZCN:
+		b *= 1e7
+	case ZCN:
+		b *= 1e10
+	}
+
+	return Balance(b), nil
+}
+
+const (
+	SAS BalanceUnit = iota
+	UZCN
+	MZCN
+	ZCN
+)
+
+type BalanceUnit byte
+
+func (unit BalanceUnit) String() string {
+	switch unit {
+	case SAS:
+		return "SAS"
+	case MZCN:
+		return "mZCN"
+	case UZCN:
+		return "uZCN"
+	case ZCN:
+		return "ZCN"
+	}
+	return ""
+}
+
+func (unit *BalanceUnit) Parse(s string) error {
+	switch s {
+	case "SAS", "sas":
+		*unit = SAS
+	case "uZCN", "uzcn":
+		*unit = UZCN
+	case "mZCN", "mzcn":
+		*unit = MZCN
+	case "ZCN", "zcn":
+		*unit = ZCN
+	default:
+		return errors.New("", "undefined balance unit: "+s)
+	}
+	return nil
+}

core/common/misc_test.go

@@ -0,0 +1,49 @@
+package common
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFormat(t *testing.T) {
+	token := Balance(129382129321)
+	require.Equal(t, "12.938 ZCN", token.Format(ZCN))
+	require.Equal(t, "12938.213 mZCN", token.Format(MZCN))
+	require.Equal(t, "12938212.932 uZCN", token.Format(UZCN))
+	require.Equal(t, "129382129321 SAS", token.Format(SAS))
+}
+
+func TestAutoFormat(t *testing.T) {
+	require.Equal(t, "239 SAS", Balance(239).AutoFormat())
+	require.Equal(t, "2.736 uZCN", Balance(27361).AutoFormat())
+	require.Equal(t, "2.387 mZCN", Balance(23872013).AutoFormat())
+	require.Equal(t, "20.383 ZCN", Balance(203827162834).AutoFormat())
+}
+
+func TestParseBalance(t *testing.T) {
+	b, err := ParseBalance("12.938 ZCN")
+	require.NoError(t, err)
+	require.Equal(t, Balance(12.938*1e10), b)
+
+	b, err = ParseBalance("12.938 mzcn")
+	require.NoError(t, err)
+	require.Equal(t, Balance(12.938*1e7), b)
+
+	b, err = ParseBalance("12.938 uZCN")
+	require.NoError(t, err)
+	require.Equal(t, Balance(12.938*1e4), b)
+
+	b, err = ParseBalance("122389 sas")
+	require.NoError(t, err)
+	require.Equal(t, Balance(122389*1e0), b)
+
+	_, err = ParseBalance("10 ")
+	require.EqualError(t, err, "invalid input: 10 ")
+
+	_, err = ParseBalance("10 zwe")
+	require.EqualError(t, err, "invalid input: 10 zwe")
+
+	_, err = ParseBalance(" 10 zcn ")
+	require.EqualError(t, err, "invalid input:  10 zcn ")
+}