* alloc.c (mark_overlay): Assume that overlay boundaries are

always markers.  Add comment.
* lread.c (read_internal_start): Use convenient validate_subarray.
Adjust docstring.
(Fread_from_string): Adjust docstring.

3 files changed, 18 insertions, 25 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index f3c881f630d..2a4ce099021 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,11 @@
+2014-10-02  Dmitry Antipov  <dmantipov@yandex.ru>
+
+        * alloc.c (mark_overlay): Assume that overlay boundaries are
+        always markers.  Add comment.
+        * lread.c (read_internal_start): Use convenient validate_subarray.
+        Adjust docstring.
+        (Fread_from_string): Adjust docstring.
+
 2014-10-02  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * lisp.h: Fix up compilation for USE_STACK_LISP_OBJECTS=false.
diff --git a/src/alloc.c b/src/alloc.c
index f656dc94216..faad0b59c87 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -6015,8 +6015,9 @@ mark_overlay (struct Lisp_Overlay *ptr)
   for (; ptr && !ptr->gcmarkbit; ptr = ptr->next)
     {
       ptr->gcmarkbit = 1;
-      mark_object (ptr->start);
-      mark_object (ptr->end);
+      /* These two are always markers and can be marked fast.  */
+      XMARKER (ptr->start)->gcmarkbit = 1;
+      XMARKER (ptr->end)->gcmarkbit = 1;
       mark_object (ptr->plist);
     }
 }
diff --git a/src/lread.c b/src/lread.c
index 0e71b13c5c8..59af12cf6da 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -2096,9 +2096,10 @@ DEFUN ("read-from-string", Fread_from_string, Sread_from_string, 1, 3, 0,
        doc: /* Read one Lisp expression which is represented as text by STRING.
 Returns a cons: (OBJECT-READ . FINAL-STRING-INDEX).
 FINAL-STRING-INDEX is an integer giving the position of the next
- remaining character in STRING.
-START and END optionally delimit a substring of STRING from which to read;
- they default to 0 and (length STRING) respectively.  */)
+remaining character in STRING.  START and END optionally delimit
+a substring of STRING from which to read;  they default to 0 and
+(length STRING) respectively.  Negative values are counted from
+the end of STRING.  */)
   (Lisp_Object string, Lisp_Object start, Lisp_Object end)
 {
   Lisp_Object ret;
@@ -2109,10 +2110,9 @@ START and END optionally delimit a substring of STRING from which to read;
 }
 
 /* Function to set up the global context we need in toplevel read
-   calls.  */
+   calls.  START and END only used when STREAM is a string.  */
 static Lisp_Object
 read_internal_start (Lisp_Object stream, Lisp_Object start, Lisp_Object end)
-/* `start', `end' only used when stream is a string.  */
 {
   Lisp_Object retval;
 
@@ -2134,25 +2134,9 @@ read_internal_start (Lisp_Object stream, Lisp_Object start, Lisp_Object end)
       else
         string = XCAR (stream);
 
-      if (NILP (end))
-        endval = SCHARS (string);
-      else
-        {
-          CHECK_NUMBER (end);
-          if (! (0 <= XINT (end) && XINT (end) <= SCHARS (string)))
-            args_out_of_range (string, end);
-          endval = XINT (end);
-        }
+      validate_subarray (string, start, end, SCHARS (string),
+                         &startval, &endval);
 
-      if (NILP (start))
-        startval = 0;
-      else
-        {
-          CHECK_NUMBER (start);
-          if (! (0 <= XINT (start) && XINT (start) <= endval))
-            args_out_of_range (string, start);
-          startval = XINT (start);
-        }
       read_from_string_index = startval;
       read_from_string_index_byte = string_char_to_byte (string, startval);
       read_from_string_limit = endval;