Update.

* resolv/inet_addr.c (inet_aton): Optimize switch statement away.

ChangeLog

@@ -1,5 +1,7 @@
 1999-04-29  Ulrich Drepper  <drepper@cygnus.com>
 
+	* resolv/inet_addr.c (inet_aton): Optimize switch statement away.
+
 	* resolv/inet_pton.c (inet_pton4): Little optimizations.
 	(inet_pton6): Likewise.
 

FAQ.in

@@ -1314,6 +1314,18 @@ interface.  For compilation with the old API, <db_185.h> has to be included
 (and not <db.h>) and you can link with either `-ldb1' or `-ldb' for either
 of the db formats.
 
+??	Autoconf's AC_CHECK_FUNC macro reports that a function exists, but
+	when I try to use it, it always returns -1 and sets errno to ENOSYS.
+
+{ZW} You are using a 2.0 Linux kernel, and the function you are trying to
+use is only implemented in 2.1/2.2.  Libc considers this to be a function
+which exists, because if you upgrade to a 2.2 kernel, it will work.  One
+such function is sigaltstack.
+
+Your program should check at runtime whether the function works, and
+implement a fallback.  Note that Autoconf cannot detect unimplemented
+functions in other systems' C libraries, so you need to do this anyway.
+
 
 ? Miscellaneous
 

resolv/inet_addr.c

@@ -99,6 +99,7 @@ inet_aton(cp, addr)
 	const char *cp;
 	struct in_addr *addr;
 {
+	static const u_int32_t max[4] = { 0xffffffff, 0xffffff, 0xffff, 0xff };
 	register u_int32_t val;	/* changed from u_long --david */
 #ifndef _LIBC
 	register int base;
@@ -113,6 +114,8 @@ inet_aton(cp, addr)
 	__set_errno (0);
 #endif
 
+	memset (parts, '\0', sizeof (parts));
+
 	c = *cp;
 	for (;;) {
 		/*
@@ -178,33 +181,14 @@ inet_aton(cp, addr)
 	 * the number of parts specified.
 	 */
 	n = pp - parts + 1;
-	switch (n) {
 
-	case 0:
-		goto ret_0;		/* initial nondigit */
+	if (n == 0	/* initial nondigit */
+	    || parts[0] > 0xff || parts[1] > 0xff || parts[2] > 0xff
+	    || val > max[n - 1])
+	  goto ret_0;
 
-	case 1:				/* a -- 32 bits */
-		break;
+	val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
 
-	case 2:				/* a.b -- 8.24 bits */
-		if (parts[0] > 0xff || val > 0xffffff)
-			goto ret_0;
-		val |= parts[0] << 24;
-		break;
-
-	case 3:				/* a.b.c -- 8.8.16 bits */
-		if (parts[0] > 0xff || parts[1] > 0xff || val > 0xffff)
-			goto ret_0;
-		val |= (parts[0] << 24) | (parts[1] << 16);
-		break;
-
-	case 4:				/* a.b.c.d -- 8.8.8.8 bits */
-		if (parts[0] > 0xff || parts[1] > 0xff || parts[2] > 0xff
-		    || val > 0xff)
-			goto ret_0;
-		val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
-		break;
-	}
 	if (addr)
 		addr->s_addr = htonl(val);
 

resolv/inet_pton.c

@@ -24,6 +24,7 @@ static char rcsid[] = "$Id$";
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <arpa/nameser.h>
+#include <ctype.h>
 #include <string.h>
 #include <errno.h>
 #include <conf/portability.h>