From 62c3e111fce0ad34960871134c2eb6da572df303 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Fri, 25 May 2012 13:48:00 -0400
Subject: [PATCH] Add set symmetric difference

---
 src/hb-set-private.hh | 5 +++++
 src/hb-set.cc         | 7 +++++++
 src/hb-set.h          | 6 ++++++
 3 files changed, 18 insertions(+)

diff --git a/src/hb-set-private.hh b/src/hb-set-private.hh
index 717e5304d..df96b9903 100644
--- a/src/hb-set-private.hh
+++ b/src/hb-set-private.hh
@@ -102,6 +102,11 @@ struct _hb_set_t
     for (unsigned int i = 0; i < ELTS; i++)
       elts[i] &= ~other->elts[i];
   }
+  inline void symmetric_difference (const hb_set_t *other)
+  {
+    for (unsigned int i = 0; i < ELTS; i++)
+      elts[i] ^= other->elts[i];
+  }
   inline hb_codepoint_t get_min (void) const
   {
     for (unsigned int i = 0; i < ELTS; i++)
diff --git a/src/hb-set.cc b/src/hb-set.cc
index 0e8addec0..7103bcd1f 100644
--- a/src/hb-set.cc
+++ b/src/hb-set.cc
@@ -164,6 +164,13 @@ hb_set_subtract (hb_set_t *set,
   set->subtract (other);
 }
 
+void
+hb_set_symmetric_difference (hb_set_t *set,
+			     hb_set_t *other)
+{
+  set->symmetric_difference (other);
+}
+
 hb_codepoint_t
 hb_set_min (hb_set_t *set)
 {
diff --git a/src/hb-set.h b/src/hb-set.h
index 35c77b8f0..38bb84b5f 100644
--- a/src/hb-set.h
+++ b/src/hb-set.h
@@ -105,9 +105,15 @@ void
 hb_set_subtract (hb_set_t *set,
 		 hb_set_t *other);
 
+void
+hb_set_symmetric_difference (hb_set_t *set,
+			     hb_set_t *other);
+
+/* Undefined if set empty */
 hb_codepoint_t
 hb_set_min (hb_set_t *set);
 
+/* Undefined if set empty */
 hb_codepoint_t
 hb_set_max (hb_set_t *set);