From 929f07dbfc8b8c40771d27a502f6e5842c1c1e90 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sat, 10 Nov 2018 15:38:48 -0500
Subject: [PATCH] Fix hb_bytes_t.cmp()

Ouch!
---
 src/hb-dsalgs.hh | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/hb-dsalgs.hh b/src/hb-dsalgs.hh
index ffa438704..e98566e75 100644
--- a/src/hb-dsalgs.hh
+++ b/src/hb-dsalgs.hh
@@ -530,10 +530,12 @@ struct hb_bytes_t
 
   inline int cmp (const hb_bytes_t &a) const
   {
-    if (len != a.len)
-      return (int) a.len - (int) len;
+    if (!len) return 0; /* glibc's memcmp() args are declared nonnull.  Meh. */
 
-    return memcmp (a.arrayZ, arrayZ, len);
+    int r = memcmp (a.arrayZ, arrayZ, len);
+    if (r) return r;
+
+    return a.len < len ? -1 : a.len > len ? +1 : 0;
   }
   static inline int cmp (const void *pa, const void *pb)
   {