From c27f5b1288e4786c27bd010a1f6b41c29ab37992 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Thu, 19 Aug 2021 10:01:24 -0600
Subject: [PATCH] [bit-set-invertible] Plug in next_range()/previous_range()

---
 src/hb-bit-set-invertible.hh | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/hb-bit-set-invertible.hh b/src/hb-bit-set-invertible.hh
index ecfe3a186..8f4b7f865 100644
--- a/src/hb-bit-set-invertible.hh
+++ b/src/hb-bit-set-invertible.hh
@@ -187,13 +187,39 @@ struct hb_bit_set_invertible_t
   }
   bool next_range (hb_codepoint_t *first, hb_codepoint_t *last) const
   {
-    /*XXX(inverted)*/
-    return s.next_range (first, last);
+    hb_codepoint_t i;
+
+    i = *last;
+    if (!next (&i))
+    {
+      *last = *first = INVALID;
+      return false;
+    }
+
+    /* TODO Speed up. */
+    *last = *first = i;
+    while (next (&i) && i == *last + 1)
+      (*last)++;
+
+    return true;
   }
   bool previous_range (hb_codepoint_t *first, hb_codepoint_t *last) const
   {
-    /*XXX(inverted)*/
-    return s.previous_range (first, last);
+    hb_codepoint_t i;
+
+    i = *first;
+    if (!previous (&i))
+    {
+      *last = *first = INVALID;
+      return false;
+    }
+
+    /* TODO Speed up. */
+    *last = *first = i;
+    while (previous (&i) && i == *first - 1)
+      (*first)--;
+
+    return true;
   }
 
   unsigned int get_population () const