getaddrinfo.c: don't require snprintf; new function: shorttostr

[Jim Meyering]

Paul, Simon,
Any objection to the changes below?

I noticed that getaddrinfo uses snprintf to perform a simple
short-to-string conversion.  For such a simple job, snprintf
and its dependent, vasnprintf, are overkill.

Instead, how about using a new shorttostr function instead?

Why a new function?
If there were an inttostr *function*, I would have been happy
to use that, but there isn't.  Substituting any of the other *tostr
functions would require using an 8-byte type on some systems,
which makes them too wasteful for me.

2006-10-21  Jim Meyering  <address@hidden>

        * lib/getaddrinfo.c (getnameinfo): Use new lightweight shorttostr,
        in place of snprintf.

        * modules/inttostr (Files): Add lib/shorttostr.c.
        * lib/shorttostr.c (inttostr): New file/function.
        * lib/inttostr.h (shorttostr): Declare.
        * m4/inttostr.m4: Add AC_LIBOBJ([shorttostr]).

Index: lib/getaddrinfo.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/getaddrinfo.c,v
retrieving revision 1.16
diff -u -r1.16 getaddrinfo.c
--- lib/getaddrinfo.c   18 Sep 2006 18:07:05 -0000      1.16
+++ lib/getaddrinfo.c   21 Oct 2006 08:37:42 -0000
@@ -39,7 +39,7 @@
 #define N_(String) String

 #include "inet_ntop.h"
-#include "snprintf.h"
+#include "intprops.h"
 #include "strdup.h"

 /* BeOS has AF_INET, but not PF_INET.  */
@@ -405,10 +405,14 @@
 #if HAVE_IPV6
       case AF_INET6:
 #endif
-       if (snprintf (service, servicelen, "%d",
-                     ntohs (((const struct sockaddr_in *) sa)->sin_port))
-           + 1 > servicelen)
-         return EAI_OVERFLOW;
+       {
+         short int port = ntohs (((const struct sockaddr_in *) sa)->sin_port);
+         char buf[INT_BUFSIZE_BOUND (port)];
+         char const *s = shorttostr (port, buf);
+         if (strlen (s) + 1 > servicelen)
+           return EAI_OVERFLOW;
+         memcpy (service, s, strlen (s) + 1);
+       }
        break;
       }

Index: lib/shorttostr.c
===================================================================
RCS file: lib/shorttostr.c
diff -N lib/shorttostr.c
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ lib/shorttostr.c    21 Oct 2006 08:37:42 -0000
@@ -0,0 +1,3 @@
+#define inttostr shorttostr
+#define inttype short int
+#include "inttostr.c"
Index: lib/inttostr.h
===================================================================
RCS file: /sources/gnulib/gnulib/lib/inttostr.h,v
retrieving revision 1.7
diff -u -r1.7 inttostr.h
--- lib/inttostr.h      21 Aug 2006 06:11:26 -0000      1.7
+++ lib/inttostr.h      21 Oct 2006 08:37:42 -0000
@@ -27,3 +27,4 @@
 char *offtostr (off_t, char *);
 char *imaxtostr (intmax_t, char *);
 char *umaxtostr (uintmax_t, char *);
+char *shorttostr (short int, char *);
Index: modules/inttostr
===================================================================
RCS file: /sources/gnulib/gnulib/modules/inttostr,v
retrieving revision 1.11
diff -u -r1.11 inttostr
--- modules/inttostr    13 Oct 2006 12:40:23 -0000      1.11
+++ modules/inttostr    21 Oct 2006 08:37:42 -0000
@@ -7,6 +7,7 @@
 lib/inttostr.h
 lib/offtostr.c
 lib/umaxtostr.c
+lib/shorttostr.c
 m4/inttostr.m4

 Depends-on:
Index: m4/inttostr.m4
===================================================================
RCS file: /sources/gnulib/gnulib/m4/inttostr.m4,v
retrieving revision 1.5
diff -u -r1.5 inttostr.m4
--- m4/inttostr.m4      21 Aug 2006 06:11:26 -0000      1.5
+++ m4/inttostr.m4      21 Oct 2006 08:37:42 -0000
@@ -1,4 +1,4 @@
-#serial 6
+#serial 7
 dnl Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -9,6 +9,7 @@
   AC_LIBOBJ([imaxtostr])
   AC_LIBOBJ([offtostr])
   AC_LIBOBJ([umaxtostr])
+  AC_LIBOBJ([shorttostr])

   gl_PREREQ_INTTOSTR
   gl_PREREQ_IMAXTOSTR
@@ -30,3 +31,6 @@

 # Prerequisites of lib/umaxtostr.c.
 AC_DEFUN([gl_PREREQ_UMAXTOSTR], [:])
+
+# Prerequisites of lib/shorttostr.c.
+AC_DEFUN([gl_PREREQ_SHORTTOSTR], [:])
Index: MODULES.html.sh
===================================================================
RCS file: /sources/gnulib/gnulib/MODULES.html.sh,v
retrieving revision 1.152
diff -u -r1.152 MODULES.html.sh
--- MODULES.html.sh     16 Oct 2006 11:55:35 -0000      1.152
+++ MODULES.html.sh     21 Oct 2006 08:37:42 -0000
@@ -1802,6 +1802,7 @@
   func_begin_table
   func_module intprops
   func_module inttostr
+  func_module shorttostr
   func_module xstrtoimax
   func_module xstrtoumax
   func_end_table