1 files changed, 170 insertions, 4 deletions

diff --git a/src/buffer.c b/src/buffer.c
index 6c797aef744..f1334c0b6a0 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1693,7 +1693,138 @@ overlays_at (pos, extend, vec_ptr, len_ptr, next_ptr, prev_ptr)
     *prev_ptr = prev;
   return idx;
 }
+
+/* Find all the overlays in the current buffer that overlap the range BEG-END
+   plus empty overlays anywhere from BEG to END.
+   Return the number found, and store them in a vector in *VEC_PTR.  
+   Store in *LEN_PTR the size allocated for the vector.
+   Store in *NEXT_PTR the next position after POS where an overlay starts,
+     or ZV if there are no more overlays.
+   Store in *PREV_PTR the previous position before POS where an overlay ends,
+     or BEGV if there are no previous overlays.
+   NEXT_PTR and/or PREV_PTR may be 0, meaning don't store that info.
+
+   *VEC_PTR and *LEN_PTR should contain a valid vector and size
+   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_in (beg, end, extend, vec_ptr, len_ptr, next_ptr, prev_ptr)
+     int beg, end;
+     int extend;
+     Lisp_Object **vec_ptr;
+     int *len_ptr;
+     int *next_ptr;
+     int *prev_ptr;
+{
+  Lisp_Object tail, overlay, ostart, oend, result;
+  int idx = 0;
+  int len = *len_ptr;
+  Lisp_Object *vec = *vec_ptr;
+  int next = ZV;
+  int prev = BEGV;
+  int inhibit_storing = 0;
+
+  for (tail = current_buffer->overlays_before;
+       GC_CONSP (tail);
+       tail = XCONS (tail)->cdr)
+    {
+      int startpos, endpos;
+
+      overlay = XCONS (tail)->car;
+
+      ostart = OVERLAY_START (overlay);
+      oend = OVERLAY_END (overlay);
+      endpos = OVERLAY_POSITION (oend);
+      if (endpos < beg)
+        {
+          if (prev < endpos)
+            prev = endpos;
+          break;
+        }
+      startpos = OVERLAY_POSITION (ostart);
+      /* Count an interval if it either overlaps the range
+         or is empty at either end of the range.  */
+      if ((beg < endpos && startpos < end)
+          || (startpos == endpos && beg == startpos)
+          || (startpos == endpos && end == startpos))
+        {
+          if (idx == len)
+            {
+              /* 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;
+            }
+
+          if (!inhibit_storing)
+            vec[idx] = overlay;
+          /* Keep counting overlays even if we can't return them all.  */
+          idx++;
+        }
+      else if (startpos < next)
+        next = startpos;
+    }
+
+  for (tail = current_buffer->overlays_after;
+       GC_CONSP (tail);
+       tail = XCONS (tail)->cdr)
+    {
+      int startpos, endpos;
+
+      overlay = XCONS (tail)->car;
+
+      ostart = OVERLAY_START (overlay);
+      oend = OVERLAY_END (overlay);
+      startpos = OVERLAY_POSITION (ostart);
+      if (end < startpos)
+        {
+          if (startpos < next)
+            next = startpos;
+          break;
+        }
+      endpos = OVERLAY_POSITION (oend);
+      if ((beg < endpos && startpos < end)
+          || (startpos == endpos && beg == startpos)
+          || (startpos == endpos && end == startpos))
+        {
+          if (idx == len)
+            {
+              if (extend)
+                {
+                  *len_ptr = len *= 2;
+                  vec = (Lisp_Object *) xrealloc (vec, len * sizeof (Lisp_Object));
+                  *vec_ptr = vec;
+                }
+              else
+                inhibit_storing = 1;
+            }
+
+          if (!inhibit_storing)
+            vec[idx] = overlay;
+          idx++;
+        }
+      else if (endpos < beg && endpos > prev)
+        prev = endpos;
+    }
 
+  if (next_ptr)
+    *next_ptr = next;
+  if (prev_ptr)
+    *prev_ptr = prev;
+  return idx;
+}
+
 /* Fast function to just test if we're at an overlay boundary.  */
 int
 overlay_touches_p (pos)
@@ -1894,7 +2025,8 @@ overlay_strings (pos, w, pstr)
                     {
                       overlay_tails_len *= 2;
                       overlay_tails = ((struct sortstr *)
-                                       xrealloc ((overlay_tails_len
+                                       xrealloc (overlay_tails,
+                                                 (overlay_tails_len
                                                   * sizeof (struct sortstr))));
                     }
                 }
@@ -1923,7 +2055,8 @@ overlay_strings (pos, w, pstr)
                     {
                       overlay_heads_len *= 2;
                       overlay_heads = ((struct sortstr *)
-                                       xrealloc ((overlay_heads_len
+                                       xrealloc (overlay_heads,
+                                                 (overlay_heads_len
                                                   * sizeof (struct sortstr))));
                     }
                 }
@@ -1963,7 +2096,8 @@ overlay_strings (pos, w, pstr)
                     {
                       overlay_tails_len *= 2;
                       overlay_tails = ((struct sortstr *)
-                                       xrealloc ((overlay_tails_len
+                                       xrealloc (overlay_tails,
+                                                 (overlay_tails_len
                                                   * sizeof (struct sortstr))));
                     }
                 }
@@ -1992,7 +2126,8 @@ overlay_strings (pos, w, pstr)
                     {
                       overlay_heads_len *= 2;
                       overlay_heads = ((struct sortstr *)
-                                       xrealloc ((overlay_heads_len
+                                       xrealloc (overlay_heads,
+                                                 (overlay_heads_len
                                                   * sizeof (struct sortstr))));
                     }
                 }
@@ -2619,6 +2754,36 @@ DEFUN ("overlays-at", Foverlays_at, Soverlays_at, 1, 1, 0,
   return result;
 }
 
+DEFUN ("overlays-in", Foverlays_in, Soverlays_in, 2, 2, 0,
+  "Return a list of the overlays that overlap region BEG ... END.\n\
+This includes empty overlays at BEG or END (as well as empty overlays\n\
+within the range.")
+  (beg, end)
+     Lisp_Object beg, end;
+{
+  int noverlays;
+  Lisp_Object *overlay_vec;
+  int len;
+  Lisp_Object result;
+
+  CHECK_NUMBER_COERCE_MARKER (beg, 0);
+  CHECK_NUMBER_COERCE_MARKER (end, 0);
+
+  len = 10;
+  overlay_vec = (Lisp_Object *) xmalloc (len * sizeof (Lisp_Object));
+
+  /* Put all the overlays we want in a vector in overlay_vec.
+     Store the length in len.  */
+  noverlays = overlays_in (XINT (beg), XINT (end), 1, &overlay_vec, &len,
+                           (int *) 0, (int *) 0);
+
+  /* Make a list of them all.  */
+  result = Flist (noverlays, overlay_vec);
+
+  xfree (overlay_vec);
+  return result;
+}
+
 DEFUN ("next-overlay-change", Fnext_overlay_change, Snext_overlay_change,
   1, 1, 0,
   "Return the next position after POS where an overlay starts or ends.\n\
@@ -3713,6 +3878,7 @@ is a member of the list.");
   defsubr (&Soverlay_buffer);
   defsubr (&Soverlay_properties);
   defsubr (&Soverlays_at);
+  defsubr (&Soverlays_in);
   defsubr (&Snext_overlay_change);
   defsubr (&Sprevious_overlay_change);
   defsubr (&Soverlay_recenter);