+
+/* return maximum length that an input of length i could decode to
+ * (this is a maximum, not a precise figure, because the actual
+ * size depends on the precise data */
+
+size_t basE91_decode_maxlen(size_t i /* must be < SIZE_T_MAX/7 */)
+{
+ size_t pairs = i / 2;
+ size_t bits = pairs * 14;
+ size_t bytes = bits / 8;
+ size_t leftover = i % 2;
+ return bytes + !!leftover;
+}