Initial Commit

base58.go

@@ -0,0 +1,57 @@
+package base58
+
+import (
+	"errors"
+	"strings"
+)
+
+// Alphabet is the default alphabet.
+const Alphabet = "123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ"
+
+// Encode converts a base10 integer to a base58 string using the default
+// alphabet.
+func Encode(num int) string {
+	return EncodeWithAlphabet(num, Alphabet)
+}
+
+// Decode converts a base58 string to a base10 integer using the default
+// alphabet.
+func Decode(str string) (int, error) {
+	return DecodeWithAlphabet(str, Alphabet)
+}
+
+// EncodeWithAlphabet converts a base10 integer to a base58 string with the
+// given alphabet.
+func EncodeWithAlphabet(num int, alphabet string) string {
+	base := len(alphabet)
+
+	str := ""
+	for num >= base {
+		mod := num % base
+		str = string(alphabet[mod]) + str
+		num = (num - mod) / base
+	}
+
+	return string(alphabet[num]) + str
+}
+
+// DecodeWithAlphabet converts a base58 string to a base10 integer with the
+// given alphabet.
+func DecodeWithAlphabet(str string, alphabet string) (int, error) {
+	base := len(alphabet)
+	num := 0
+	multi := 1
+
+	for i := len(str); i > 0; i-- {
+		char := string(str[i-1])
+		index := strings.Index(alphabet, char)
+		if index == -1 {
+			errorMsg := "\"" + str + "\" is not a valid base58 string."
+			return -1, errors.New(errorMsg)
+		}
+		num += multi * index
+		multi = multi * base
+	}
+
+	return num, nil
+}