Basexx - Convert between digit strings and various number bases

This is basexx, a package for converting numbers to digit strings in various bases and vice versa.

Usage

To get the Base30 encoding of the number 412:

var sb strings.Builder
if err := basexx.EncodeInt64(&sb, 412, basexx.Base30); err != nil { ... }
result := sb.String()

To decode the Base30 digit string "fr":

result, err := basexx.DecodeString("fr", basexx.Base30)

To convert a digit string x in base from to a new digit string in base to:

result, err := basexx.Convert(x, from, to)

To define your own new number base:

// ReverseBase10 uses digits '9' through '0' just to mess with you.
type ReverseBase10 struct{}

func (ReverseBase10) N() int64 { return 10 }

func (ReverseBase10) Digit(val int64) (byte, error) {
  if val < 0 || val > 9 {
    return 0, errors.New("digit value out of range")
  }
  return byte('9' - val), nil
}

func (ReverseBase10) Val(digit byte) (int64, error) {
  if digit < '0’ || digit > '9' {
    return 0, errors.New("invalid encoded digit")
  }
  return int64(9 - (digit - '0’))
}