Initial import

protocol/aprs/base91.go

@@ -0,0 +1,29 @@
+package aprs
+
+import (
+	"fmt"
+	"strings"
+)
+
+func base91Decode(s string) (n int, err error) {
+	for i, l := 0, len(s); i < l; i++ {
+		c := s[i]
+		if c < 33 || c > 122 {
+			return 0, fmt.Errorf("aprs: invalid base-91 encoding char %q (%d)", c, c)
+		}
+
+		n *= 91
+		n += int(c) - 33
+	}
+	return
+}
+
+func base91Encode(n int) string {
+	var s []string
+	for n > 0 {
+		c := n % 91
+		n /= 91
+		s = append([]string{string(byte(c) + 33)}, s...)
+	}
+	return strings.Join(s, "")
+}