X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/13002885275be0499d0131d4d1823d5e5a6a1be6..aec3bf9f49c8c0d0356a0e57f362bd0e23206e7d:/src/marker.c

diff --git a/src/marker.c b/src/marker.c
index 0df03e0173..2f91bdf972 100644
--- a/src/marker.c
+++ b/src/marker.c
@@ -1,5 +1,6 @@
 /* Markers: examining, setting and deleting.
-   Copyright (C) 1985, 1997-1998, 2001-2012  Free Software Foundation, Inc.
+   Copyright (C) 1985, 1997-1998, 2001-2013 Free Software Foundation,
+   Inc.
 
 This file is part of GNU Emacs.
 
@@ -126,6 +127,12 @@ clear_charpos_cache (struct buffer *b)
     }									\
 }
 
+static void
+CHECK_MARKER (Lisp_Object x)
+{
+  CHECK_TYPE (MARKERP (x), Qmarkerp, x);
+}
+
 /* Return the byte position corresponding to CHARPOS in B.  */
 
 ptrdiff_t
@@ -498,20 +505,38 @@ set_marker_internal (Lisp_Object marker, Lisp_Object position,
     {
       register ptrdiff_t charpos, bytepos;
 
-      CHECK_NUMBER_COERCE_MARKER (position);
-      charpos = clip_to_bounds (restricted ? BUF_BEGV (b) : BUF_BEG (b),
-                               XINT (position),
-                               restricted ? BUF_ZV (b) : BUF_Z (b));
-      bytepos = buf_charpos_to_bytepos (b, charpos);
+      /* Do not use CHECK_NUMBER_COERCE_MARKER because we
+	 don't want to call buf_charpos_to_bytepos if POSITION
+	 is a marker and so we know the bytepos already.  */
+      if (INTEGERP (position))
+	charpos = XINT (position), bytepos = -1;
+      else if (MARKERP (position))
+	{
+	  charpos = XMARKER (position)->charpos;
+	  bytepos = XMARKER (position)->bytepos;
+	}
+      else
+	wrong_type_argument (Qinteger_or_marker_p, position);
+
+      charpos = clip_to_bounds
+	(restricted ? BUF_BEGV (b) : BUF_BEG (b), charpos,
+	 restricted ? BUF_ZV (b) : BUF_Z (b));
+      if (bytepos == -1)
+	bytepos = buf_charpos_to_bytepos (b, charpos);
+      else
+	bytepos = clip_to_bounds
+	  (restricted ? BUF_BEGV_BYTE (b) : BUF_BEG_BYTE (b),
+	   bytepos, restricted ? BUF_ZV_BYTE (b) : BUF_Z_BYTE (b));
+
       attach_marker (m, b, charpos, bytepos);
     }
   return marker;
 }
 
 DEFUN ("set-marker", Fset_marker, Sset_marker, 2, 3, 0,
-       doc: /* Position MARKER before character number POSITION in BUFFER,
-which defaults to the current buffer.  If POSITION is nil,
-makes marker point nowhere so it no longer slows down
+       doc: /* Position MARKER before character number POSITION in BUFFER.
+If BUFFER is omitted or nil, it defaults to the current buffer.  If
+POSITION is nil, makes marker point nowhere so it no longer slows down
 editing in any buffer.  Returns MARKER.  */)
   (Lisp_Object marker, Lisp_Object position, Lisp_Object buffer)
 {