(overlays_at): New arg EXTEND.

(Foverlays_at, Fnext_overlay_change): Pass 1.

1 files changed, 39 insertions, 12 deletions

diff --git a/src/buffer.c b/src/buffer.c
index 2104226b338..db9dfbcfed5 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1202,11 +1202,17 @@ a non-nil `permanent-local' property are not eliminated by this function.")
      or ZV if there are no more overlays.
 
    *VEC_PTR and *LEN_PTR should contain a valid vector and size
-   when this function is called.  */
+   when this function is called.
+
+   If EXTEND is non-zero, we make the vector bigger if necessary.
+   If EXTEND is zero, we never extend the vector,
+   and we store only as many overlays as will fit.
+   But we still return the total number of overlays.  */
 
 int
-overlays_at (pos, vec_ptr, len_ptr, next_ptr)
+overlays_at (pos, extend, vec_ptr, len_ptr, next_ptr)
      int pos;
+     int extend;
      Lisp_Object **vec_ptr;
      int *len_ptr;
      int *next_ptr;
@@ -1216,6 +1222,8 @@ overlays_at (pos, vec_ptr, len_ptr, next_ptr)
   int len = *len_ptr;
   Lisp_Object *vec = *vec_ptr;
   int next = ZV;
+  int inhibit_storing = 0;
+
   for (tail = current_buffer->overlays_before;
        CONSP (tail);
        tail = XCONS (tail)->cdr)
@@ -1235,11 +1243,22 @@ overlays_at (pos, vec_ptr, len_ptr, next_ptr)
         {
           if (idx == len)
             {
-              *len_ptr = len *= 2;
-              vec = (Lisp_Object *) xrealloc (vec, len * sizeof (Lisp_Object));
-              *vec_ptr = vec;
+              /* The supplied vector is full.
+                 Either make it bigger, or don't store any more in it.  */
+              if (extend)
+                {
+                  *len_ptr = len *= 2;
+                  vec = (Lisp_Object *) xrealloc (vec, len * sizeof (Lisp_Object));
+                  *vec_ptr = vec;
+                }
+              else
+                inhibit_storing = 1;
             }
-          vec[idx++] = overlay;
+
+          if (!inhibit_storing)
+            vec[idx] = overlay;
+          /* Keep counting overlays even if we can't return them all.  */
+          idx++;
         }
       else if (startpos < next)
         next = startpos;
@@ -1268,11 +1287,19 @@ overlays_at (pos, vec_ptr, len_ptr, next_ptr)
         {
           if (idx == len)
             {
-              *len_ptr = len *= 2;
-              vec = (Lisp_Object *) xrealloc (vec, len * sizeof (Lisp_Object));
-              *vec_ptr = vec;
+              if (extend)
+                {
+                  *len_ptr = len *= 2;
+                  vec = (Lisp_Object *) xrealloc (vec, len * sizeof (Lisp_Object));
+                  *vec_ptr = vec;
+                }
+              else
+                inhibit_storing = 1;
             }
-          vec[idx++] = overlay;
+
+          if (!inhibit_storing)
+            vec[idx] = overlay;
+          idx++;
         }
     }
 
@@ -1658,7 +1685,7 @@ DEFUN ("overlays-at", Foverlays_at, Soverlays_at, 1, 1, 0,
 
   /* Put all the overlays we want in a vector in overlay_vec.
      Store the length in len.  */
-  noverlays = overlays_at (XINT (pos), &overlay_vec, &len, &endpos);
+  noverlays = overlays_at (XINT (pos), 1, &overlay_vec, &len, &endpos);
 
   /* Make a list of them all.  */
   result = Flist (noverlays, overlay_vec);
@@ -1688,7 +1715,7 @@ DEFUN ("next-overlay-change", Fnext_overlay_change, Snext_overlay_change,
   /* Put all the overlays we want in a vector in overlay_vec.
      Store the length in len.
      endpos gets the position where the next overlay starts.  */
-  noverlays = overlays_at (XINT (pos), &overlay_vec, &len, &endpos);
+  noverlays = overlays_at (XINT (pos), 1, &overlay_vec, &len, &endpos);
 
   /* If any of these overlays ends before endpos,
      use its ending point instead.  */