* buffer.h (decode_buffer): New function.

* buffer.c (Fbuffer_name, Fbuffer_file_name, Fbuffer_base_buffer)
(Fbuffer_local_variables, Fbuffer_modified_p, Fbuffer_modified_tick)
(Fbuffer_chars_modified_tick, Fdelete_all_overlays):
* data.c (Flocal_variables_p):
* fileio.c (Fverify_visited_file_modtime):
* marker.c (live_buffer): Use it.

6 files changed, 29 insertions, 108 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 3ce27b1ce19..0a0b0934968 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -7,6 +7,14 @@
         * lisp.h (egetenv): ... because of a new inline function used to
         avoid calls to strlen for a compile-time constants.
 
+        * buffer.h (decode_buffer): New function.
+        * buffer.c (Fbuffer_name, Fbuffer_file_name, Fbuffer_base_buffer)
+        (Fbuffer_local_variables, Fbuffer_modified_p, Fbuffer_modified_tick)
+        (Fbuffer_chars_modified_tick, Fdelete_all_overlays):
+        * data.c (Flocal_variables_p):
+        * fileio.c (Fverify_visited_file_modtime):
+        * marker.c (live_buffer): Use it.
+
 2014-09-01  Dmitry Antipov  <dmantipov@yandex.ru>
 
         Avoid extra calls to strlen in filesystem I/O routines.
diff --git a/src/buffer.c b/src/buffer.c
index d2c7729d1c2..ee1359611c3 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1134,10 +1134,7 @@ BUFFER defaults to the current buffer.
 Return nil if BUFFER has been killed.  */)
   (register Lisp_Object buffer)
 {
-  if (NILP (buffer))
-    return BVAR (current_buffer, name);
-  CHECK_BUFFER (buffer);
-  return BVAR (XBUFFER (buffer), name);
+  return BVAR (decode_buffer (buffer), name);
 }
 
 DEFUN ("buffer-file-name", Fbuffer_file_name, Sbuffer_file_name, 0, 1, 0,
@@ -1145,10 +1142,7 @@ DEFUN ("buffer-file-name", Fbuffer_file_name, Sbuffer_file_name, 0, 1, 0,
 No argument or nil as argument means use the current buffer.  */)
   (register Lisp_Object buffer)
 {
-  if (NILP (buffer))
-    return BVAR (current_buffer, filename);
-  CHECK_BUFFER (buffer);
-  return BVAR (XBUFFER (buffer), filename);
+  return BVAR (decode_buffer (buffer), filename);
 }
 
 DEFUN ("buffer-base-buffer", Fbuffer_base_buffer, Sbuffer_base_buffer,
@@ -1158,21 +1152,8 @@ If BUFFER is not indirect, return nil.
 BUFFER defaults to the current buffer.  */)
   (register Lisp_Object buffer)
 {
-  struct buffer *base;
-  Lisp_Object base_buffer;
-
-  if (NILP (buffer))
-    base = current_buffer->base_buffer;
-  else
-    {
-      CHECK_BUFFER (buffer);
-      base = XBUFFER (buffer)->base_buffer;
-    }
-
-  if (! base)
-    return Qnil;
-  XSETBUFFER (base_buffer, base);
-  return base_buffer;
+  struct buffer *base = decode_buffer (buffer)->base_buffer;
+  return base ? (XSETBUFFER (buffer, base), buffer) : Qnil;
 }
 
 DEFUN ("buffer-local-value", Fbuffer_local_value,
@@ -1297,18 +1278,8 @@ 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)
 {
-  register struct buffer *buf;
-  register Lisp_Object result;
-
-  if (NILP (buffer))
-    buf = current_buffer;
-  else
-    {
-      CHECK_BUFFER (buffer);
-      buf = XBUFFER (buffer);
-    }
-
-  result = buffer_lisp_local_variables (buf, 0);
+  register struct buffer *buf = decode_buffer (buffer);
+  register Lisp_Object result = buffer_lisp_local_variables (buf, 0);
 
   /* Add on all the variables stored in special slots.  */
   {
@@ -1337,15 +1308,7 @@ DEFUN ("buffer-modified-p", Fbuffer_modified_p, Sbuffer_modified_p,
 No argument or nil as argument means use current buffer as BUFFER.  */)
   (register Lisp_Object buffer)
 {
-  register struct buffer *buf;
-  if (NILP (buffer))
-    buf = current_buffer;
-  else
-    {
-      CHECK_BUFFER (buffer);
-      buf = XBUFFER (buffer);
-    }
-
+  register struct buffer *buf = decode_buffer (buffer);
   return BUF_SAVE_MODIFF (buf) < BUF_MODIFF (buf) ? Qt : Qnil;
 }
 
@@ -1451,16 +1414,7 @@ text in that buffer is changed.  It wraps around occasionally.
 No argument or nil as argument means use current buffer as BUFFER.  */)
   (register Lisp_Object buffer)
 {
-  register struct buffer *buf;
-  if (NILP (buffer))
-    buf = current_buffer;
-  else
-    {
-      CHECK_BUFFER (buffer);
-      buf = XBUFFER (buffer);
-    }
-
-  return make_number (BUF_MODIFF (buf));
+  return make_number (BUF_MODIFF (decode_buffer (buffer)));
 }
 
 DEFUN ("buffer-chars-modified-tick", Fbuffer_chars_modified_tick,
@@ -1475,16 +1429,7 @@ between these calls.  No argument or nil as argument means use current
 buffer as BUFFER.  */)
   (register Lisp_Object buffer)
 {
-  register struct buffer *buf;
-  if (NILP (buffer))
-    buf = current_buffer;
-  else
-    {
-      CHECK_BUFFER (buffer);
-      buf = XBUFFER (buffer);
-    }
-
-  return make_number (BUF_CHARS_MODIFF (buf));
+  return make_number (BUF_CHARS_MODIFF (decode_buffer (buffer)));
 }
 
 DEFUN ("rename-buffer", Frename_buffer, Srename_buffer, 1, 2,
@@ -4137,17 +4082,7 @@ BUFFER omitted or nil means delete all overlays of the current
 buffer.  */)
   (Lisp_Object buffer)
 {
-  register struct buffer *buf;
-
-  if (NILP (buffer))
-    buf = current_buffer;
-  else
-    {
-      CHECK_BUFFER (buffer);
-      buf = XBUFFER (buffer);
-    }
-
-  delete_all_overlays (buf);
+  delete_all_overlays (decode_buffer (buffer));
   return Qnil;
 }
 
diff --git a/src/buffer.h b/src/buffer.h
index fd989925976..7511a5aab1e 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -1088,6 +1088,13 @@ extern void mmap_set_vars (bool);
 extern void restore_buffer (Lisp_Object);
 extern void set_buffer_if_live (Lisp_Object);
 
+INLINE
+struct buffer *
+decode_buffer (Lisp_Object b)
+{
+  return NILP (b) ? current_buffer : (CHECK_BUFFER (b), XBUFFER (b));
+}
+
 /* Set the current buffer to B.
 
    We previously set windows_or_buffers_changed here to invalidate
diff --git a/src/data.c b/src/data.c
index 3e651414e68..aa344dfaf2d 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1954,17 +1954,9 @@ DEFUN ("local-variable-p", Flocal_variable_p, Slocal_variable_p,
 BUFFER defaults to the current buffer.  */)
   (register Lisp_Object variable, Lisp_Object buffer)
 {
-  register struct buffer *buf;
+  register struct buffer *buf = decode_buffer (buffer);
   struct Lisp_Symbol *sym;
 
-  if (NILP (buffer))
-    buf = current_buffer;
-  else
-    {
-      CHECK_BUFFER (buffer);
-      buf = XBUFFER (buffer);
-    }
-
   CHECK_SYMBOL (variable);
   sym = XSYMBOL (variable);
 
diff --git a/src/fileio.c b/src/fileio.c
index bd1e650c427..f4aa33d1f1d 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -5324,20 +5324,12 @@ If BUF is omitted or nil, it defaults to the current buffer.
 See Info node `(elisp)Modification Time' for more details.  */)
   (Lisp_Object buf)
 {
-  struct buffer *b;
+  struct buffer *b = decode_buffer (buf);
   struct stat st;
   Lisp_Object handler;
   Lisp_Object filename;
   struct timespec mtime;
 
-  if (NILP (buf))
-    b = current_buffer;
-  else
-    {
-      CHECK_BUFFER (buf);
-      b = XBUFFER (buf);
-    }
-
   if (!STRINGP (BVAR (b, filename))) return Qt;
   if (b->modtime.tv_nsec == UNKNOWN_MODTIME_NSECS) return Qt;
 
diff --git a/src/marker.c b/src/marker.c
index 91fcea5f25f..d377efbc4fa 100644
--- a/src/marker.c
+++ b/src/marker.c
@@ -455,21 +455,8 @@ attach_marker (struct Lisp_Marker *m, struct buffer *b,
 static struct buffer *
 live_buffer (Lisp_Object buffer)
 {
-  struct buffer *b;
-
-  if (NILP (buffer))
-    {
-      b = current_buffer;
-      eassert (BUFFER_LIVE_P (b));
-    }
-  else
-    {
-      CHECK_BUFFER (buffer);
-      b = XBUFFER (buffer);
-      if (!BUFFER_LIVE_P (b))
-       b = NULL;
-    }
-  return b;
+  struct buffer *b = decode_buffer (buffer);
+  return BUFFER_LIVE_P (b) ? b : NULL;
 }
 
 /* Internal function to set MARKER in BUFFER at POSITION.  Non-zero