Add function to check if something is a value utf8 string

src/include/libradius.h

@@ -725,6 +725,7 @@ size_t		fr_bin2hex(char *hex, uint8_t const *bin, size_t inlen);
 size_t		fr_hex2bin(uint8_t *bin, size_t outlen, char const *hex, size_t inlen);
 uint32_t	fr_strtoul(char const *value, char **end);
 bool		is_whitespace(char const *value);
+bool		is_printable(void const *value, size_t len);
 bool		is_integer(char const *value);
 bool		is_zero(char const *value);
 

src/lib/misc.c

@@ -1139,6 +1139,30 @@ bool is_whitespace(char const *value)
 	return true;
 }
 
+/** Check whether the string is made up of printable UTF8 chars
+ *
+ * @param value to check.
+ * @param len of value.
+ *
+ * @return
+ *	- true if the string is printable.
+ *	- false if the string contains non printable chars
+ */
+ bool is_printable(void const *value, size_t len)
+ {
+ 	uint8_t	const *p = value;
+ 	int	clen;
+ 	size_t	i;
+
+ 	for (i = 0; i < len; i++) {
+ 		clen = fr_utf8_char(p);
+ 		if (clen == 0) return false;
+ 		i += (size_t)clen;
+ 		p += clen;
+ 	}
+ 	return true;
+ }
+
 /** Check whether the string is all numbers
  *
  * @return