From 09c7a2d6bf00dc902343e999f92cac0e8146f949 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Mon, 8 Aug 2016 17:28:54 -0700
Subject: [PATCH] Limit bits-per-feature to eight

Limits number of alternatives per glyph per feature to 255, so be it.
That's better than possibly breaking shaping because of one bad feature
value.
---
 src/hb-ot-map.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 35550af..17e3f40 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -193,7 +193,8 @@ hb_ot_map_builder_t::compile (hb_ot_map_t &m)
       /* Uses the global bit */
       bits_needed = 0;
     else
-      bits_needed = _hb_bit_storage (info->max_value);
+      /* Limit to 8 bits per feature. */
+      bits_needed = MIN(8u, _hb_bit_storage (info->max_value));
 
     if (!info->max_value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
       continue; /* Feature disabled, or not enough bits. */
-- 
2.7.4