Avoid comparison of unsigned < 0

[lilypond.git] / lily / grob.cc

diff --git a/lily/grob.cc b/lily/grob.cc
index fa8e1f684307453ec9d90b1d4998c9747b2e212a..d36a6721301430fcae21ae84f268c089c423aaaf 100644 (file)
--- a/lily/grob.cc
+++ b/lily/grob.cc
@@ -483,8 +483,6 @@ Grob::pure_height (Grob *refp, int start, int end)
 Interval
 Grob::maybe_pure_extent (Grob *refp, Axis a, bool pure, int start, int end)
 {
-  if (pure && a != Y_AXIS)
-    programming_error ("tried to get pure width");
   return (pure && a == Y_AXIS) ? pure_height (refp, start, end) : extent (refp, a);
 }
 
@@ -515,15 +513,39 @@ Grob::less (Grob *g1, Grob *g2)
 Grob *
 Grob::common_refpoint (Grob const *s, Axis a) const
 {
-  /* I don't like the quadratic aspect of this code, but I see no
-     other way.  The largest chain of parents might be 10 high or so,
-     so it shouldn't be a real issue.  */
-  for (Grob const *c = this; c; c = c->dim_cache_[a].parent_)
-    for (Grob const *d = s; d; d = d->dim_cache_[a].parent_)
-      if (d == c)
-        return (Grob *) d;
 
-  return 0;
+  /* Catching the trivial cases is likely costlier than just running
+     through: one can't avoid going to the respective chain ends
+     anyway.  We might save the second run through when the chain ends
+     differ, but keeping track of the ends makes the loop more costly.
+  */
+
+  int balance = 0;
+  Grob const *c;
+  Grob const *d;
+
+  for (c = this; c; ++balance)
+    c = c->dim_cache_[a].parent_;
+
+  for (d = s; d; --balance)
+    d = d->dim_cache_[a].parent_;
+
+  /* Cut down ancestry to same size */
+
+  for (c = this; balance > 0; --balance)
+    c = c->dim_cache_[a].parent_;
+
+  for (d = s; balance < 0; ++balance)
+    d = d->dim_cache_[a].parent_;
+
+  /* Now find point where our lineages converge */
+  while (c != d)
+    {
+      c = c->dim_cache_[a].parent_;
+      d = d->dim_cache_[a].parent_;
+    }
+
+  return (Grob *) c;
 }
 
 void
@@ -576,7 +598,7 @@ Grob::fixup_refpoint ()
   VERTICAL ORDERING
 ****************************************************************/
 
-Grob*
+Grob *
 get_maybe_root_vertical_alignment (Grob *g, Grob *maybe)
 {
   if (!g)
@@ -587,13 +609,13 @@ get_maybe_root_vertical_alignment (Grob *g, Grob *maybe)
 
 }
 
-Grob*
+Grob *
 Grob::get_root_vertical_alignment (Grob *g)
 {
   return get_maybe_root_vertical_alignment (g, 0);
 }
 
-Grob*
+Grob *
 Grob::get_vertical_axis_group (Grob *g)
 {
   if (!g)
@@ -622,6 +644,18 @@ Grob::get_vertical_axis_group_index (Grob *g)
 
 bool
 Grob::vertical_less (Grob *g1, Grob *g2)
+{
+  return internal_vertical_less (g1, g2, false);
+}
+
+bool
+Grob::pure_vertical_less (Grob *g1, Grob *g2)
+{
+  return internal_vertical_less (g1, g2, true);
+}
+
+bool
+Grob::internal_vertical_less (Grob *g1, Grob *g2, bool pure)
 {
   Grob *vag = get_root_vertical_alignment (g1);
   if (!vag)
@@ -636,6 +670,12 @@ Grob::vertical_less (Grob *g1, Grob *g2)
 
   extract_grob_set (vag, "elements", elts);
 
+  if (ag1 == ag2 && !pure)
+    {
+      Grob *common = g1->common_refpoint (g2, Y_AXIS);
+      return g1->relative_coordinate (common, Y_AXIS) > g2->relative_coordinate (common, Y_AXIS);
+    }
+
   for (vsize i = 0; i < elts.size (); i++)
     {
       if (elts[i] == ag1)
@@ -746,6 +786,7 @@ ADD_INTERFACE (Grob,
                "extra-X-extent "
                "extra-Y-extent "
                "extra-offset "
+               "forced-spacing "
                "interfaces "
                "layer "
                "meta "