Comments on new resolv.c additions

[Denys Vlasenko]

commit 7f74de5d4d6d10baafab4b37bb3d472f5c5f0e8c
Author: Daniel Mack <zonque at gmail.com>
Date:   Wed Jul 13 00:30:54 2011 +0200

    inet/resolv: add res_ninit and res_nclose

    Some reordering of existing functions was necessary in order to provide
    this functionality.

    Signed-off-by: Daniel Mack <zonque at gmail.com>
...
...
-void res_close(void)
+static void
+__res_iclose(res_state statp, int free_addr)
 {
        __UCLIBC_MUTEX_LOCK(__resolv_lock);
        __close_nameservers();
@@ -3552,6 +3566,26 @@ void res_close(void)
        memset(&_res, 0, sizeof(_res));
        __UCLIBC_MUTEX_UNLOCK(__resolv_lock);
 }

Obviously, neither statp nor free_addr parameters are used. Why are they there?

+void
+res_nclose(res_state statp)
+{
+       __res_iclose(statp, 1);
+}
+
+#ifdef __UCLIBC_HAS_BSD_RES_CLOSE__
+void res_close(void)
+{
+       __res_iclose(&_res, 0);
+}

and since __res_iclose() ignores its parameters,
these two functions are essentially the same. Is it intended?
If yes, can we just alias their names?




commit 5f6fe1fca1e60923503dd391a60b2ad5b9aead31
Author: Daniel Mack <zonque at gmail.com>
Date:   Wed Jul 13 00:30:52 2011 +0200

    inet/resolv: add ns_initparse, ns_parserr, ns_skiprr and ns_msg_getflag

    There are build 'ifdef L_ns_parse'.

    Signed-off-by: Daniel Mack <zonque at gmail.com>
...
...
-extern struct _ns_flagdata _ns_flagdata[];
+extern const struct _ns_flagdata _ns_flagdata[];

This table is used exactly in one place. You can make it static
(and smaller).





commit e5153a77782bf7042f50b97959536f3f181bad99
Author: Daniel Mack <zonque at gmail.com>
Date:   Wed Jul 13 00:30:49 2011 +0200

    inet/resolv: add ns_name_pton, ns_name_pack and ns_name_compress

    These are built '#ifdef L_ns_name'

    Signed-off-by: Daniel Mack <zonque at gmail.com>
...
...
+static const char digitvalue[256] = {
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/
+        0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1, /*64*/
+       -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/
+       -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+       -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/
+};
...
...
+                               if (!isxdigit(c&0xff))
+                                       return (EINVAL);
+                               value <<= 4;
+                               value += digitvalue[(int)c];

Eek... there are much more compact ways to convert hex to binary.


+                       if ((bitlen = *(lp + 1)) == 0)

It's not necessary to cram as much as possible into one line.
The assignment can well be done as a separate statement, and code
will be easier to read. gcc will generate the same code anyway.


-- 
vda