Minor cleanup of recent strlen-avoiding patch.

* src/fileio.c (CHECK_LENGTH): Remove.
Rewrite callers so that they don't need it.
(Fexpand_file_name) [DOS_NT]: Fix a case where directory length
variable wasn't set.

diff --git a/src/ChangeLog b/src/ChangeLog
index 0a0b0934968efb283733e2a84d6fafd629dea003..fbe5f597d9c83eb646100ae82bd9f8a654e7760d 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,11 @@
+2014-09-02  Paul Eggert  <eggert@cs.ucla.edu>
+
+       Minor cleanup of recent strlen-avoiding patch.
+       * fileio.c (CHECK_LENGTH): Remove.
+       Rewrite callers so that they don't need it.
+       (Fexpand_file_name) [DOS_NT]: Fix a case where directory length
+       variable wasn't set.
+
 2014-09-02  Dmitry Antipov  <dmantipov@yandex.ru>
 
        * fileio.c (CHECK_LENGTH): New macro.

diff --git a/src/buffer.c b/src/buffer.c
index ee1359611c310f2d89a867e1241bf32705c6cabe..62431cb8fe1b61047ba3ea137bb96cf0c622b0be 100644 (file)
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1276,10 +1276,10 @@ Most elements look like (SYMBOL . VALUE), describing one variable.
 For a symbol that is locally unbound, just the symbol appears in the value.
 Note that storing new VALUEs in these elements doesn't change the variables.
 No argument or nil as argument means use current buffer as BUFFER.  */)
-  (register Lisp_Object buffer)
+  (Lisp_Object buffer)
 {
-  register struct buffer *buf = decode_buffer (buffer);
-  register Lisp_Object result = buffer_lisp_local_variables (buf, 0);
+  struct buffer *buf = decode_buffer (buffer);
+  Lisp_Object result = buffer_lisp_local_variables (buf, 0);
 
   /* Add on all the variables stored in special slots.  */
   {
@@ -1306,9 +1306,9 @@ DEFUN ("buffer-modified-p", Fbuffer_modified_p, Sbuffer_modified_p,
        0, 1, 0,
        doc: /* Return t if BUFFER was modified since its file was last read or saved.
 No argument or nil as argument means use current buffer as BUFFER.  */)
-  (register Lisp_Object buffer)
+  (Lisp_Object buffer)
 {
-  register struct buffer *buf = decode_buffer (buffer);
+  struct buffer *buf = decode_buffer (buffer);
   return BUF_SAVE_MODIFF (buf) < BUF_MODIFF (buf) ? Qt : Qnil;
 }
 

diff --git a/src/data.c b/src/data.c
index aa344dfaf2da0bb7dfade2062d466c7059790303..a155fe6f84abe3a811cd040c65e90071af092a36 100644 (file)
--- a/src/data.c
+++ b/src/data.c
@@ -1952,9 +1952,9 @@ DEFUN ("local-variable-p", Flocal_variable_p, Slocal_variable_p,
        1, 2, 0,
        doc: /* Non-nil if VARIABLE has a local binding in buffer BUFFER.
 BUFFER defaults to the current buffer.  */)
-  (register Lisp_Object variable, Lisp_Object buffer)
+  (Lisp_Object variable, Lisp_Object buffer)
 {
-  register struct buffer *buf = decode_buffer (buffer);
+  struct buffer *buf = decode_buffer (buffer);
   struct Lisp_Symbol *sym;
 
   CHECK_SYMBOL (variable);

diff --git a/src/fileio.c b/src/fileio.c
index f4aa33d1f1dfa69f4fdfee175789e3b48bb5c9d1..80b7abc5c744e2e85787613ff35c45b6137f2998 100644 (file)
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -847,15 +847,6 @@ probably use `make-temp-file' instead, except in three circumstances:
   return make_temp_name (prefix, 0);
 }
 
-/* The following function does a lot of work with \0-terminated strings.
-   To avoid extra calls to strlen and strcat, we maintain an important
-   lengths explicitly.  This macro is used to check whether we're in sync.  */
-#ifdef ENABLE_CHECKING
-#define CHECK_LENGTH(str, len) (eassert (strlen (str) == len), len)
-#else
-#define CHECK_LENGTH(str, len) (len)
-#endif /* ENABLE_CHECKING */
-
 DEFUN ("expand-file-name", Fexpand_file_name, Sexpand_file_name, 1, 2, 0,
        doc: /* Convert filename NAME to absolute, and canonicalize it.
 Second arg DEFAULT-DIRECTORY is directory to start with if NAME is relative
@@ -885,7 +876,9 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
   /* These point to SDATA and need to be careful with string-relocation
      during GC (via DECODE_FILE).  */
   char *nm;
+  char *nmlim;
   const char *newdir;
+  const char *newdirlim;
   /* This should only point to alloca'd data.  */
   char *target;
 
@@ -893,10 +886,10 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
   struct passwd *pw;
 #ifdef DOS_NT
   int drive = 0;
-  bool collapse_newdir = 1;
+  bool collapse_newdir = true;
   bool is_escaped = 0;
 #endif /* DOS_NT */
-  ptrdiff_t length, newdirlen, nmlen, nbytes;
+  ptrdiff_t length, nbytes;
   Lisp_Object handler, result, handled_name;
   bool multibyte;
   Lisp_Object hdir;
@@ -1027,14 +1020,13 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
 
   /* Make a local copy of NAME to protect it from GC in DECODE_FILE below.  */
   nm = xlispstrdupa (name);
-  nmlen = SBYTES (name);
+  nmlim = nm + SBYTES (name);
 
 #ifdef DOS_NT
   /* Note if special escape prefix is present, but remove for now.  */
   if (nm[0] == '/' && nm[1] == ':')
     {
       is_escaped = 1;
-      nmlen -= 2;
       nm += 2;
     }
 
@@ -1044,7 +1036,6 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
   if (IS_DRIVE (nm[0]) && IS_DEVICE_SEP (nm[1]))
     {
       drive = (unsigned char) nm[0];
-      nmlen -= 2;
       nm += 2;
     }
 
@@ -1053,7 +1044,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
      colon when stripping the drive letter.  Otherwise, this expands to
      "//somedir".  */
   if (drive && IS_DIRECTORY_SEP (nm[0]) && IS_DIRECTORY_SEP (nm[1]))
-    nmlen--, nm++;
+    nm++;
 
   /* Discard any previous drive specifier if nm is now in UNC format.  */
   if (IS_DIRECTORY_SEP (nm[0]) && IS_DIRECTORY_SEP (nm[1])
@@ -1114,8 +1105,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
          if (IS_DIRECTORY_SEP (nm[1]))
            {
              if (strcmp (nm, SSDATA (name)) != 0)
-               name = make_specified_string
-                 (nm, -1, CHECK_LENGTH (nm, nmlen), multibyte);
+               name = make_specified_string (nm, -1, nmlim - nm, multibyte);
            }
          else
 #endif
@@ -1136,8 +1126,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
 #else /* not DOS_NT */
          if (strcmp (nm, SSDATA (name)) == 0)
            return name;
-         return make_specified_string
-           (nm, -1, CHECK_LENGTH (nm, nmlen), multibyte);
+         return make_specified_string (nm, -1, nmlim - nm, multibyte);
 #endif /* not DOS_NT */
        }
     }
@@ -1158,8 +1147,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
      return an absolute name, if the final prefix is not absolute we
      append it to the current working directory.  */
 
-  newdir = 0;
-  newdirlen = -1;
+  newdir = newdirlim = 0;
 
   if (nm[0] == '~')            /* prefix ~ */
     {
@@ -1169,8 +1157,8 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
          Lisp_Object tem;
 
          if (!(newdir = egetenv ("HOME")))
-           newdir = "";
-         nmlen--, nm++;
+           newdir = newdirlim = "";
+         nm++;
          /* `egetenv' may return a unibyte string, which will bite us since
             we expect the directory to be multibyte.  */
 #ifdef WINDOWSNT
@@ -1184,15 +1172,15 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
          else
 #endif
            tem = build_string (newdir);
-         newdirlen = SBYTES (tem);
+         newdirlim = newdir + SBYTES (tem);
          if (multibyte && !STRING_MULTIBYTE (tem))
            {
              hdir = DECODE_FILE (tem);
              newdir = SSDATA (hdir);
-             newdirlen = SBYTES (hdir);
+             newdirlim = newdir + SBYTES (hdir);
            }
 #ifdef DOS_NT
-         collapse_newdir = 0;
+         collapse_newdir = false;
 #endif
        }
       else                     /* ~user/filename */
@@ -1216,17 +1204,16 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
                 bite us since we expect the directory to be
                 multibyte.  */
              tem = build_string (newdir);
-             newdirlen = SBYTES (tem);
+             newdirlim = newdir + SBYTES (tem);
              if (multibyte && !STRING_MULTIBYTE (tem))
                {
                  hdir = DECODE_FILE (tem);
                  newdir = SSDATA (hdir);
-                 newdirlen = SBYTES (hdir);
+                 newdirlim = newdir + SBYTES (hdir);
                }
-             nmlen -= (p - nm);
              nm = p;
 #ifdef DOS_NT
-             collapse_newdir = 0;
+             collapse_newdir = false;
 #endif
            }
 
@@ -1252,8 +1239,8 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
              Lisp_Object tem = build_string (adir);
 
              tem = DECODE_FILE (tem);
-             newdirlen = SBYTES (tem);
-             memcpy (adir, SSDATA (tem), newdirlen + 1);
+             newdirlim = adir + SBYTES (tem);
+             memcpy (adir, SSDATA (tem), SBYTES (tem) + 1);
            }
        }
       if (!adir)
@@ -1264,7 +1251,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
          adir[1] = ':';
          adir[2] = '/';
          adir[3] = 0;
-         newdirlen = 3;
+         newdirlim = adir + 3;
        }
       newdir = adir;
     }
@@ -1285,13 +1272,12 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
       && !newdir)
     {
       newdir = SSDATA (default_directory);
-      newdirlen = SBYTES (default_directory);
+      newdirlim = newdir + SBYTES (default_directory);
 #ifdef DOS_NT
       /* Note if special escape prefix is present, but remove for now.  */
       if (newdir[0] == '/' && newdir[1] == ':')
        {
          is_escaped = 1;
-         newdirlen -= 2;
          newdir += 2;
        }
 #endif
@@ -1327,18 +1313,19 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
          if (IS_DRIVE (newdir[0]) && IS_DEVICE_SEP (newdir[1]))
            {
              drive = (unsigned char) newdir[0];
-             newdirlen -= 2;
              newdir += 2;
            }
          if (!IS_DIRECTORY_SEP (nm[0]))
            {
+             ptrdiff_t nmlen = nmlim - nm;
+             ptrdiff_t newdirlen = newdirlim - newdir;
              char *tmp = alloca (newdirlen + file_name_as_directory_slop
-                                 + CHECK_LENGTH (nm, nmlen) + 1);
-             nbytes = file_name_as_directory (tmp, newdir, newdirlen,
-                                              multibyte);
-             memcpy (tmp + nbytes, nm, nmlen + 1);
-             nmlen += nbytes;
+                                 + nmlen + 1);
+             ptrdiff_t dlen = file_name_as_directory (tmp, newdir, newdirlen,
+                                                      multibyte);
+             memcpy (tmp + dlen, nm, nmlen + 1);
              nm = tmp;
+             nmlim = nm + dlen + nmlen;
            }
          adir = alloca (adir_size);
          if (drive)
@@ -1353,11 +1340,11 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
              Lisp_Object tem = build_string (adir);
 
              tem = DECODE_FILE (tem);
-             newdirlen = SBYTES (tem);
-             memcpy (adir, SSDATA (tem), newdirlen + 1);
+             newdirlim = adir + SBYTES (tem);
+             memcpy (adir, SSDATA (tem), SBYTES (tem) + 1);
            }
          else
-           newdirlen = strlen (adir);
+           newdirlim = adir + strlen (adir);
          newdir = adir;
        }
 
@@ -1365,7 +1352,6 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
       if (IS_DRIVE (newdir[0]) && IS_DEVICE_SEP (newdir[1]))
        {
          drive = newdir[0];
-         newdirlen -= 2;
          newdir += 2;
        }
 
@@ -1377,36 +1363,31 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
          if (IS_DIRECTORY_SEP (newdir[0]) && IS_DIRECTORY_SEP (newdir[1])
              && !IS_DIRECTORY_SEP (newdir[2]))
            {
-             char *adir = strcpy (alloca (newdirlen + 1), newdir);
+             char *adir = strcpy (alloca (newdirlim - newdir + 1), newdir);
              char *p = adir + 2;
              while (*p && !IS_DIRECTORY_SEP (*p)) p++;
              p++;
              while (*p && !IS_DIRECTORY_SEP (*p)) p++;
              *p = 0;
              newdir = adir;
-             newdirlen = strlen (adir);
+             newdirlim = newdir + strlen (adir);
            }
          else
 #endif
-           newdirlen = 0, newdir = "";
+           newdir = newdirlim = "";
        }
     }
 #endif /* DOS_NT */
 
-  if (newdir)
-    {
-      /* Ignore any slash at the end of newdir, unless newdir is
-        just "/" or "//".  */
-      length = CHECK_LENGTH (newdir, newdirlen);
-      while (length > 1 && IS_DIRECTORY_SEP (newdir[length - 1])
-            && ! (length == 2 && IS_DIRECTORY_SEP (newdir[0])))
-       length--;
-    }
-  else
-    length = 0;
+  /* Ignore any slash at the end of newdir, unless newdir is
+     just "/" or "//".  */
+  length = newdirlim - newdir;
+  while (length > 1 && IS_DIRECTORY_SEP (newdir[length - 1])
+        && ! (length == 2 && IS_DIRECTORY_SEP (newdir[0])))
+    length--;
 
   /* Now concatenate the directory and name to new space in the stack frame.  */
-  tlen = length + file_name_as_directory_slop + CHECK_LENGTH (nm, nmlen) + 1;
+  tlen = length + file_name_as_directory_slop + (nmlim - nm) + 1;
 #ifdef DOS_NT
   /* Reserve space for drive specifier and escape prefix, since either
      or both may need to be inserted.  (The Microsoft x86 compiler
@@ -1442,7 +1423,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
        nbytes = file_name_as_directory (target, newdir, length, multibyte);
     }
 
-  memcpy (target + nbytes, nm, nmlen + 1);
+  memcpy (target + nbytes, nm, nmlim - nm + 1);
 
   /* Now canonicalize by removing `//', `/.' and `/foo/..' if they
      appear.  */

diff --git a/src/lisp.h b/src/lisp.h
index cac536943a55ecf625b46200afcf3a22c38d5329..53bfd7c4daf9b1a3485a0d0060d419f3ae1d6352 100644 (file)
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -4444,12 +4444,10 @@ extern void xputenv (const char *);
 
 extern char *egetenv_internal (const char *, ptrdiff_t);
 
-/* VAR is usually a compile-time constant, so the
-   call to strlen is likely to be optimized away.  */
-
 INLINE char *
-egetenv(const char *var)
+egetenv (const char *var)
 {
+  /* When VAR is a string literal, strlen can be optimized away.  */
   return egetenv_internal (var, strlen (var));
 }