* lisp.h (lispstpcpy): Rename from lispstrcpy, and act like stpcpy.

All callers changed.
* xterm.c (x_term_init): Use new functionality to avoid two needs
to compute a string length.

src/ChangeLog

 2014-09-23  Paul Eggert  <eggert@cs.ucla.edu>
+	* lisp.h (lispstpcpy): Rename from lispstrcpy, and act like stpcpy.
+	All callers changed.
+	* xterm.c (x_term_init): Use new functionality to avoid two needs
+	to compute a string length.
+
 	* dispextern.h, xdisp.c (window_box_right_offset): Now static.
 2014-09-23  Dmitry Antipov  <dmantipov@yandex.ru>

src/callproc.c

@@ -1235,7 +1235,7 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp,
 #endif
     temp = pwd_var + 4;
     memcpy (pwd_var, "PWD=", 4);
-    lispstrcpy (temp, current_dir);
+    lispstpcpy (temp, current_dir);
 
 #ifndef DOS_NT
     /* We can't signal an Elisp error here; we're in a vfork.  Since

src/dbusbind.c

@@ -761,7 +761,7 @@ xd_append_arg (int dtype, Lisp_Object object, DBusMessageIter *iter)
 		&& STRINGP (CAR_SAFE (XD_NEXT_VALUE (object)))
 		&& NILP (CDR_SAFE (XD_NEXT_VALUE (object))))
 	      {
-		lispstrcpy (signature, CAR_SAFE (XD_NEXT_VALUE (object)));
+		lispstpcpy (signature, CAR_SAFE (XD_NEXT_VALUE (object)));
 		object = CDR_SAFE (XD_NEXT_VALUE (object));
 	      }
 

src/doc.c

@@ -121,7 +121,7 @@ get_doc_string (Lisp_Object filepos, bool unibyte, bool definition)
       if (minsize < 8)
 	minsize = 8;
       name = SAFE_ALLOCA (minsize + SCHARS (file) + 8);
-      lispstrcpy (name, docdir);
+      lispstpcpy (name, docdir);
       strcat (name, SSDATA (file));
     }
   else

src/font.c

@@ -4266,7 +4266,7 @@ the consecutive wildcards are folded into one.  */)
 	{
 	  if (NILP (fold_wildcards))
 	    return font_name;
-	  lispstrcpy (name, font_name);
+	  lispstpcpy (name, font_name);
 	  namelen = SBYTES (font_name);
 	  goto done;
 	}

src/frame.c

@@ -4036,8 +4036,8 @@ xrdb_get_resource (XrmDatabase rdb, Lisp_Object attribute, Lisp_Object class, Li
 
   /* Start with emacs.FRAMENAME for the name (the specific one)
      and with `Emacs' for the class key (the general one).  */
-  lispstrcpy (name_key, Vx_resource_name);
-  lispstrcpy (class_key, Vx_resource_class);
+  lispstpcpy (name_key, Vx_resource_name);
+  lispstpcpy (class_key, Vx_resource_class);
 
   strcat (class_key, ".");
   strcat (class_key, SSDATA (class));

src/lisp.h

@@ -4463,12 +4463,15 @@ extern char *xstrdup (const char *) ATTRIBUTE_MALLOC;
 extern char *xlispstrdup (Lisp_Object) ATTRIBUTE_MALLOC;
 extern void dupstring (char **, char const *);
 
-/* Like strcpy but uses known length of a Lisp string.  */
+/* Make DEST a copy of STRING's data.  Return a pointer to DEST's terminating
+   null byte.  This is like stpcpy, except the source is a Lisp string.  */
 
 INLINE char *
-lispstrcpy (const char *dest, Lisp_Object string)
+lispstpcpy (char *dest, Lisp_Object string)
 {
-  return memcpy ((void *) dest, SSDATA (string), SBYTES (string) + 1);
+  ptrdiff_t len = SBYTES (string);
+  memcpy (dest, SDATA (string), len + 1);
+  return dest + len;
 }
 
 extern void xputenv (const char *);

src/process.c

@@ -2989,7 +2989,7 @@ usage: (make-network-process &rest ARGS)  */)
       address_un.sun_family = AF_LOCAL;
       if (sizeof address_un.sun_path <= SBYTES (service))
 	error ("Service name too long");
-      lispstrcpy (address_un.sun_path, service);
+      lispstpcpy (address_un.sun_path, service);
       ai.ai_addr = (struct sockaddr *) &address_un;
       ai.ai_addrlen = sizeof address_un;
       goto open_socket;
@@ -3680,7 +3680,7 @@ network_interface_info (Lisp_Object ifname)
 
   if (sizeof rq.ifr_name <= SBYTES (ifname))
     error ("interface name too long");
-  lispstrcpy (rq.ifr_name, ifname);
+  lispstpcpy (rq.ifr_name, ifname);
 
   s = socket (AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
   if (s < 0)

src/w32fns.c

@@ -5339,7 +5339,7 @@ terminate Emacs if we can't open the connection.
   {
     char basename[ MAX_PATH ], *str;
 
-    lispstrcpy (basename, Vinvocation_name);
+    lispstpcpy (basename, Vinvocation_name);
     str = strrchr (basename, '.');
     if (str) *str = 0;
     Vinvocation_name = build_string (basename);

src/w32proc.c

@@ -1647,7 +1647,7 @@ sys_spawnve (int mode, char *cmdname, char **argv, char **envp)
 	strcpy (cmdname, egetenv ("CMDPROXY"));
       else
 	{
-	  lispstrcpy (cmdname, Vinvocation_directory);
+	  lispstpcpy (cmdname, Vinvocation_directory);
 	  strcat (cmdname, "cmdproxy.exe");
 	}
 

src/xfns.c

@@ -4289,7 +4289,7 @@ select_visual (struct x_display_info *dpyinfo)
       int i, class = -1;
       XVisualInfo vinfo;
 
-      lispstrcpy (s, value);
+      lispstpcpy (s, value);
       dash = strchr (s, '-');
       if (dash)
 	{

src/xfont.c

@@ -541,7 +541,7 @@ xfont_list (struct frame *f, Lisp_Object spec)
 	    if (STRINGP (XCAR (alter))
 		&& ((r - name) + SBYTES (XCAR (alter))) < 256)
 	      {
-		lispstrcpy (r, XCAR (alter));
+		lispstpcpy (r, XCAR (alter));
 		list = xfont_list_pattern (display, name, registry, script);
 		if (! NILP (list))
 		  break;

src/xsmfns.c

@@ -418,7 +418,7 @@ x_session_initialize (struct x_display_info *dpyinfo)
   emacs_program[0] = '\0';
 
   if (! EQ (Vinvocation_directory, Qnil))
-    lispstrcpy (emacs_program, Vinvocation_directory);
+    lispstpcpy (emacs_program, Vinvocation_directory);
   strcat (emacs_program, SSDATA (Vinvocation_name));
 
   /* The SM protocol says all callbacks are mandatory, so set up all

src/xterm.c

@@ -10902,8 +10902,9 @@ x_term_init (Lisp_Object display_name, char *xrm_option, char *resource_name)
   dpyinfo->x_id = ++x_display_id;
   dpyinfo->x_id_name = xmalloc (SBYTES (Vinvocation_name)
 				+ SBYTES (Vsystem_name) + 2);
-  strcat (strcat (lispstrcpy (dpyinfo->x_id_name, Vinvocation_name), "@"),
-	  SSDATA (Vsystem_name));
+  char *nametail = lispstpcpy (dpyinfo->x_id_name, Vinvocation_name);
+  *nametail++ = '@';
+  lispstpcpy (nametail, Vsystem_name);
 
   /* Figure out which modifier bits mean what.  */
   x_find_modifier_meanings (dpyinfo);