Avoid some strlen work, primarily via strnlen

* admin/merge-gnulib (GNULIB_MODULES): Add strnlen.
* lib-src/etags.c (find_entries):
* src/emacs.c (main):
* src/nsmenu.m (parseKeyEquiv:):
* src/nsterm.m (ns_xlfd_to_fontname):
* src/term.c (vfatal):
Prefer !*X to !strlen (X).
* lib-src/etags.c (pfnote, add_regex):
* lib-src/pop.c (pop_open):
* lib-src/update-game-score.c (main):
* lwlib/lwlib.c (lw_separator_p):
* src/doprnt.c (doprnt):
* src/emacs.c (main):
* src/inotify.c (inotifyevent_to_event):
* src/keyboard.c (menu_separator_name_p, parse_tool_bar_item):
* src/sysdep.c (get_current_dir_name_or_unreachable):
* src/xdisp.c (store_mode_line_string):
Use strnlen to avoid unnecessary work with strlen.
* lib-src/etags.c (Prolog_functions, prolog_pr)
(Erlang_functions, erlang_func):
Prefer ptrdiff_t to size_t when either will do.
(prolog_pr, erlang_func): New arg LASTLEN, to avoid
unnecessary strlen call. All callers changed.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/strnlen.c, m4/strnlen.m4: New files, copied from Gnulib.
* lwlib/lwlib.c (lw_separator_p):
* src/json.c (json_has_prefix):
Use strncmp to avoid unecessary work with strlen + memcmp.
* src/process.c (set_socket_option): Use SBYTES instead of strlen.

3 files changed, 69 insertions, 92 deletions

diff --git a/lib-src/etags.c b/lib-src/etags.c
index 442b622cceb..036c485d0bb 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -1811,7 +1811,7 @@ find_entries (FILE *inf)
         }
       *cp = '\0';
 
-      if (strlen (lp) > 0)
+      if (*lp)
         {
           lang = get_language_from_interpreter (lp);
           if (lang != NULL && lang->function != NULL)
@@ -2012,7 +2012,7 @@ pfnote (char *name, bool is_func, char *linestart, int linelen, int lno,
   np->left = np->right = NULL;
   if (CTAGS && !cxref_style)
     {
-      if (strlen (linestart) < 50)
+      if (strnlen (linestart, 50) < 50)
         np->regex = concat (linestart, "$", "");
       else
         np->regex = savenstr (linestart, 50);
@@ -5883,20 +5883,15 @@ HTML_labels (FILE *inf)
  * Original code by Sunichirou Sugou (1989)
  * Rewritten by Anders Lindgren (1996)
  */
-static size_t prolog_pr (char *, char *);
+static ptrdiff_t prolog_pr (char *, char *, ptrdiff_t);
 static void prolog_skip_comment (linebuffer *, FILE *);
 static size_t prolog_atom (char *, size_t);
 
 static void
 Prolog_functions (FILE *inf)
 {
-  char *cp, *last;
-  size_t len;
-  size_t allocated;
-
-  allocated = 0;
-  len = 0;
-  last = NULL;
+  char *cp, *last = NULL;
+  ptrdiff_t lastlen = 0, allocated = 0;
 
   LOOP_ON_INPUT_LINES (inf, lb, cp)
     {
@@ -5906,17 +5901,22 @@ Prolog_functions (FILE *inf)
         continue;
       else if (cp[0] == '/' && cp[1] == '*')    /* comment. */
         prolog_skip_comment (&lb, inf);
-      else if ((len = prolog_pr (cp, last)) > 0)
+      else
         {
-          /* Predicate or rule.  Store the function name so that we
-             only generate a tag for the first clause.  */
-          if (last == NULL)
-            last = xnew (len + 1, char);
-          else if (len + 1 > allocated)
-            xrnew (last, len + 1, char);
-          allocated = len + 1;
-          memcpy (last, cp, len);
-          last[len] = '\0';
+          ptrdiff_t len = prolog_pr (cp, last, lastlen);
+          if (0 < len)
+            {
+              /* Store the predicate name to avoid generating duplicate
+                 tags later.  */
+              if (allocated <= len)
+                {
+                  xrnew (last, len + 1, char);
+                  allocated = len + 1;
+                }
+              memcpy (last, cp, len);
+              last[len] = '\0';
+              lastlen = len;
+            }
         }
     }
   free (last);
@@ -5949,33 +5949,25 @@ prolog_skip_comment (linebuffer *plb, FILE *inf)
  * Return the size of the name of the predicate or rule, or 0 if no
  * header was found.
  */
-static size_t
-prolog_pr (char *s, char *last)
-
-                                /* Name of last clause. */
+static ptrdiff_t
+prolog_pr (char *s, char *last, ptrdiff_t lastlen)
 {
-  size_t pos;
-  size_t len;
-
-  pos = prolog_atom (s, 0);
-  if (! pos)
+  ptrdiff_t len = prolog_atom (s, 0);
+  if (len == 0)
     return 0;
+  ptrdiff_t pos = skip_spaces (s + len) - s;
 
-  len = pos;
-  pos = skip_spaces (s + pos) - s;
-
+  /* Save only the first clause.  */
   if ((s[pos] == '.'
        || (s[pos] == '(' && (pos += 1))
        || (s[pos] == ':' && s[pos + 1] == '-' && (pos += 2)))
-      && (last == NULL          /* save only the first clause */
-          || len != strlen (last)
-          || !strneq (s, last, len)))
-        {
-          make_tag (s, len, true, s, pos, lineno, linecharno);
-          return len;
-        }
-  else
-    return 0;
+      && ! (lastlen == len && memcmp (s, last, len) == 0))
+    {
+      make_tag (s, len, true, s, pos, lineno, linecharno);
+      return len;
+    }
+
+  return 0;
 }
 
 /*
@@ -6043,21 +6035,15 @@ prolog_atom (char *s, size_t pos)
  * Assumes that Erlang functions start at column 0.
  * Original code by Anders Lindgren (1996)
  */
-static int erlang_func (char *, char *, int *);
+static int erlang_func (char *, char *, ptrdiff_t, ptrdiff_t *);
 static void erlang_attribute (char *);
 static int erlang_atom (char *);
 
 static void
 Erlang_functions (FILE *inf)
 {
-  char *cp, *last;
-  int len;
-  int allocated;
-  int name_offset = 0;
-
-  allocated = 0;
-  len = 0;
-  last = NULL;
+  char *cp, *last = NULL;
+  ptrdiff_t lastlen = 0, allocated = 0;
 
   LOOP_ON_INPUT_LINES (inf, lb, cp)
     {
@@ -6078,19 +6064,23 @@ Erlang_functions (FILE *inf)
               last = NULL;
             }
         }
-      else if ((len = erlang_func (cp, last, &name_offset)) > 0)
+      else
         {
-          /*
-           * Function.  Store the function name so that we only
-           * generates a tag for the first clause.
-           */
-          if (last == NULL)
-            last = xnew (len + 1, char);
-          else if (len + 1 > allocated)
-            xrnew (last, len + 1, char);
-          allocated = len + 1;
-          memcpy (last, cp + name_offset, len);
-          last[len] = '\0';
+          ptrdiff_t name_offset;
+          ptrdiff_t len = erlang_func (cp, last, lastlen, &name_offset);
+          if (0 < len)
+            {
+              /* Store the function name to avoid generating duplicate
+                 tags later.  */
+              if (allocated <= len)
+                {
+                  xrnew (last, len + 1, char);
+                  allocated = len + 1;
+                }
+              memcpy (last, cp + name_offset, len);
+              last[len] = '\0';
+              lastlen = len;
+            }
         }
     }
   free (last);
@@ -6108,40 +6098,27 @@ Erlang_functions (FILE *inf)
  * was found.
  */
 static int
-erlang_func (char *s, char *last, int *name_offset)
-
-                                /* Name of last clause. */
+erlang_func (char *s, char *last, ptrdiff_t lastlen, ptrdiff_t *name_offset)
 {
-  int pos;
-  int len;
   char *name = s;
-
-  pos = erlang_atom (s);
-  if (pos < 1)
+  ptrdiff_t len = erlang_atom (s);
+  if (len == 0)
     return 0;
-
-  len = pos;
-  pos = skip_spaces (s + pos) - s;
+  ptrdiff_t pos = skip_spaces (s + len) - s;
 
   /* If the name is quoted, the quotes are not part of the name. */
-  if (len > 2 && name[0] == '\'' && name[len - 1] == '\'')
-    {
-      *name_offset = 1;
-      name++;
-      len -= 2;
-    }
-  else
-    *name_offset = 0;
+  bool quoted = 2 < len && name[0] == '\'' && name[len - 1] == '\'';
+  name += quoted;
+  len -= 2 * quoted;
 
   /* Save only the first clause. */
   if (s[pos++] == '('
-      && (last == NULL
-          || len != (int)strlen (last)
-          || !strneq (name, last, len)))
-        {
-          make_tag (name, len, true, s, pos, lineno, linecharno);
-          return len;
-        }
+      && ! (lastlen == len && memcmp (name, last, len) == 0))
+    {
+      make_tag (s, len, true, s, pos, lineno, linecharno);
+      *name_offset = quoted;
+      return len;
+    }
 
   return 0;
 }
@@ -6363,7 +6340,7 @@ add_regex (char *regexp_pattern, language *lang)
     single_line = false;        /* dot does not match newline */
 
 
-  if (strlen (regexp_pattern) < 3)
+  if (strnlen (regexp_pattern, 3) < 3)
     {
       error ("null regexp");
       return;
diff --git a/lib-src/pop.c b/lib-src/pop.c
index c14808d6d37..e4bd6c04965 100644
--- a/lib-src/pop.c
+++ b/lib-src/pop.c
@@ -285,7 +285,7 @@ pop_open (char *host, char *username, char *password, int flags)
   /*
    * I really shouldn't use the pop_error variable like this, but....
    */
-  if (strlen (username) > ERROR_MAX - 6)
+  if (strnlen (username, ERROR_MAX - 6 + 1) == ERROR_MAX - 6 + 1)
     {
       pop_close (server);
       strcpy (pop_error,
@@ -299,7 +299,7 @@ pop_open (char *host, char *username, char *password, int flags)
       return (0);
     }
 
-  if (strlen (password) > ERROR_MAX - 6)
+  if (strnlen (password, ERROR_MAX - 6 + 1) == ERROR_MAX - 6 + 1)
     {
       pop_close (server);
       strcpy (pop_error,
diff --git a/lib-src/update-game-score.c b/lib-src/update-game-score.c
index 8a6f46b38e7..782425186e8 100644
--- a/lib-src/update-game-score.c
+++ b/lib-src/update-game-score.c
@@ -240,7 +240,7 @@ main (int argc, char **argv)
   if (! user)
     lose_syserr ("Couldn't determine user id");
   data = argv[optind + 2];
-  if (strlen (data) > MAX_DATA_LEN)
+  if (strnlen (data, MAX_DATA_LEN + 1) == MAX_DATA_LEN + 1)
     data[MAX_DATA_LEN] = '\0';
   nl = strchr (data, '\n');
   if (nl)