+ /* Append a two-byte length and the string to the buffer. Length is in
+ * network byte order. */
+
+static inline int hex_encode_size(int binsize) { return binsize*2 + 1; }
+extern void hex_encode(const uint8_t *bin, int binsize, char *buf);
+ /* Convert a byte array to hex into a supplied buffer. */
+extern string_t hex_encode_alloc(const uint8_t *bin, int binsize);
+ /* Returns the result in a freshly allocated string. */
+
+extern bool_t hex_decode(uint8_t *buffer, int32_t buflen, int32_t *outlen,
+ cstring_t hb, bool_t allow_odd_nibble);
+ /* Convert a hex string to binary, storing the result in buffer. If
+ * allow_odd_nibble then it is acceptable if the input is an odd number of
+ * digits, and an additional leading zero digit is assumed; otherwise, this
+ * is not acceptable and the conversion fails.
+ *
+ * The input is processed left to right until it is consumed, the buffer is
+ * full, or an error is encountered in the input. The length of output
+ * produced is stored in *outlen. Returns true if the entire input was
+ * processed without error; otherwise false. */