Added currency converting

ethutil/common.go

+package ethutil
+
+import (
+	"fmt"
+	"math/big"
+)
+
+var (
+	Ether  = BigPow(10, 18)
+	Finney = BigPow(10, 15)
+	Szabo  = BigPow(10, 12)
+	Vito   = BigPow(10, 9)
+	Turing = BigPow(10, 6)
+	Eins   = BigPow(10, 3)
+	Wei    = big.NewInt(1)
+)
+
+func CurrencyToString(num *big.Int) string {
+	switch {
+	case num.Cmp(Ether) >= 0:
+		return fmt.Sprintf("%v Ether", new(big.Int).Div(num, Ether))
+	case num.Cmp(Finney) >= 0:
+		return fmt.Sprintf("%v Finney", new(big.Int).Div(num, Finney))
+	case num.Cmp(Szabo) >= 0:
+		return fmt.Sprintf("%v Szabo", new(big.Int).Div(num, Szabo))
+	case num.Cmp(Vito) >= 0:
+		return fmt.Sprintf("%v Vito", new(big.Int).Div(num, Vito))
+	case num.Cmp(Turing) >= 0:
+		return fmt.Sprintf("%v Turing", new(big.Int).Div(num, Turing))
+	case num.Cmp(Eins) >= 0:
+		return fmt.Sprintf("%v Eins", new(big.Int).Div(num, Eins))
+	}
+
+	return fmt.Sprintf("%v Wei", num)
+}

ethutil/common_test.go

+package ethutil
+
+import (
+	"fmt"
+	"math/big"
+	"testing"
+)
+
+func TestCommon(t *testing.T) {
+	fmt.Println(CurrencyToString(BigPow(10, 19)))
+	fmt.Println(CurrencyToString(BigPow(10, 16)))
+	fmt.Println(CurrencyToString(BigPow(10, 13)))
+	fmt.Println(CurrencyToString(BigPow(10, 10)))
+	fmt.Println(CurrencyToString(BigPow(10, 7)))
+	fmt.Println(CurrencyToString(BigPow(10, 4)))
+	fmt.Println(CurrencyToString(big.NewInt(10)))
+}