str: make single-character evaluations normalized

Basic character checks are mostly done with defines, but some were
functions.  Move the outliers to defines as well.

Authored-By: Brad House (@bradh352)

src/lib/include/ares_str.h

@@ -52,11 +52,6 @@ CARES_EXTERN void          ares__str_trim(char *str);
 CARES_EXTERN unsigned char ares__tolower(unsigned char c);
 CARES_EXTERN ares_bool_t   ares__memeq_ci(const unsigned char *ptr,
                                           const unsigned char *val, size_t len);
-
-CARES_EXTERN ares_bool_t   ares__isspace(int ch);
-CARES_EXTERN ares_bool_t   ares__isprint(int ch);
-CARES_EXTERN ares_bool_t   ares__is_hostnamech(int ch);
-
 CARES_EXTERN ares_bool_t   ares__is_hostname(const char *str);
 
 /*! Validate the string provided is printable.  The length specified must be
@@ -74,18 +69,55 @@ CARES_EXTERN ares_bool_t   ares__str_isprint(const char *str, size_t len);
 
 /* We only care about ASCII rules */
 #define ares__isascii(x) (((unsigned char)x) <= 127)
+
 #define ares__isdigit(x) \
   (((unsigned char)x) >= '0' && ((unsigned char)x) <= '9')
+
 #define ares__isxdigit(x)                                      \
   (ares__isdigit(x) ||                                         \
    (((unsigned char)x) >= 'a' && ((unsigned char)x) <= 'f') || \
    (((unsigned char)x) >= 'A' && ((unsigned char)x) <= 'F'))
+
 #define ares__isupper(x) \
   (((unsigned char)x) >= 'A' && ((unsigned char)x) <= 'Z')
+
 #define ares__islower(x) \
   (((unsigned char)x) >= 'a' && ((unsigned char)x) <= 'z')
+
 #define ares__isalpha(x) (ares__islower(x) || ares__isupper(x))
 
+#define ares__isspace(x) (((unsigned char)(x)) == '\r' || \
+                          ((unsigned char)(x)) == '\t' || \
+                          ((unsigned char)(x)) == ' '  || \
+                          ((unsigned char)(x)) == '\v' || \
+                          ((unsigned char)(x)) == '\f' || \
+                          ((unsigned char)(x)) == '\n')
+
+#define ares__isprint(x) (((unsigned char)(x)) >= 0x20 && \
+                          ((unsigned char)(x)) <= 0x7E)
+
+/* Character set allowed by hostnames.  This is to include the normal
+ * domain name character set plus:
+ *  - underscores which are used in SRV records.
+ *  - Forward slashes such as are used for classless in-addr.arpa
+ *    delegation (CNAMEs)
+ *  - Asterisks may be used for wildcard domains in CNAMEs as seen in the
+ *    real world.
+ * While RFC 2181 section 11 does state not to do validation,
+ * that applies to servers, not clients.  Vulnerabilities have been
+ * reported when this validation is not performed.  Security is more
+ * important than edge-case compatibility (which is probably invalid
+ * anyhow).
+ * [A-Za-z0-9-*._/]
+ */
+#define ares__is_hostnamech(x) (ares__isalpha(x) || ares__isdigit(x) || \
+                                ((unsigned char)(x)) == '-' || \
+                                ((unsigned char)(x)) == '.' || \
+                                ((unsigned char)(x)) == '_' || \
+                                ((unsigned char)(x)) == '/' || \
+                                ((unsigned char)(x)) == '*')
+
+
 /*! Compare two strings (for sorting)
  *
  *  Treats NULL and "" strings as equivalent

src/lib/str/ares_str.c

@@ -198,63 +198,6 @@ ares_bool_t ares__memeq_ci(const unsigned char *ptr, const unsigned char *val,
   return ARES_TRUE;
 }
 
-ares_bool_t ares__isspace(int ch)
-{
-  switch (ch) {
-    case '\r':
-    case '\t':
-    case ' ':
-    case '\v':
-    case '\f':
-    case '\n':
-      return ARES_TRUE;
-    default:
-      break;
-  }
-  return ARES_FALSE;
-}
-
-ares_bool_t ares__isprint(int ch)
-{
-  if (ch >= 0x20 && ch <= 0x7E) {
-    return ARES_TRUE;
-  }
-  return ARES_FALSE;
-}
-
-/* Character set allowed by hostnames.  This is to include the normal
- * domain name character set plus:
- *  - underscores which are used in SRV records.
- *  - Forward slashes such as are used for classless in-addr.arpa
- *    delegation (CNAMEs)
- *  - Asterisks may be used for wildcard domains in CNAMEs as seen in the
- *    real world.
- * While RFC 2181 section 11 does state not to do validation,
- * that applies to servers, not clients.  Vulnerabilities have been
- * reported when this validation is not performed.  Security is more
- * important than edge-case compatibility (which is probably invalid
- * anyhow). */
-ares_bool_t ares__is_hostnamech(int ch)
-{
-  /* [A-Za-z0-9-*._/]
-   * Don't use isalnum() as it is locale-specific
-   */
-  if (ch >= 'A' && ch <= 'Z') {
-    return ARES_TRUE;
-  }
-  if (ch >= 'a' && ch <= 'z') {
-    return ARES_TRUE;
-  }
-  if (ch >= '0' && ch <= '9') {
-    return ARES_TRUE;
-  }
-  if (ch == '-' || ch == '.' || ch == '_' || ch == '/' || ch == '*') {
-    return ARES_TRUE;
-  }
-
-  return ARES_FALSE;
-}
-
 ares_bool_t ares__is_hostname(const char *str)
 {
   size_t i;