-SR_PRIV int data_hex(struct sr_output *o, const char *data_in,
- uint64_t length_in, char **data_out, uint64_t *length_out)
+SR_PRIV int data_hex(struct sr_output *o, const uint8_t *data_in,
+ uint64_t length_in, uint8_t **data_out,
+ uint64_t *length_out)