commit 333173103bb618f721bd25d0c565a3c3c9ea224e
author Behdad Esfahbod <behdad@behdad.org> Mon Aug 08 17:24:04 2016 -0700
committer Behdad Esfahbod <behdad@behdad.org> Mon Aug 08 17:28:14 2016 -0700
tree 05844724c9bbf19c593a6e501b84b90052f806fd
parent 10a0d4aa2254f783758bb908175047df3a0b41fe

Fix sign of shift operators

This one:

  map->mask = (1 << (next_bit + bits_needed)) - (1 << next_bit);

before the fix, the shift was done as an int, causing overflow
if it ever got to 1 << 31.  Sprinkle 'u's around.

Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=634805

src/hb-buffer-private.hh

diff --git a/src/hb-buffer-private.hh b/src/hb-buffer-private.hh
index ed592f4..bca308d 100644
--- a/src/hb-buffer-private.hh
+++ b/src/hb-buffer-private.hh
@@ -134,7 +134,7 @@
 #ifndef HB_NDEBUG
     unsigned int end = start + count;
     assert (end <= 8);
-    unsigned int bits = (1<<end) - (1<<start);
+    unsigned int bits = (1u<<end) - (1u<<start);
     assert (0 == (allocated_var_bits & bits));
     allocated_var_bits |= bits;
 #endif
@@ -144,7 +144,7 @@
 #ifndef HB_NDEBUG
     unsigned int end = start + count;
     assert (end <= 8);
-    unsigned int bits = (1<<end) - (1<<start);
+    unsigned int bits = (1u<<end) - (1u<<start);
     assert (bits == (allocated_var_bits & bits));
     allocated_var_bits &= ~bits;
 #endif
@@ -154,7 +154,7 @@
 #ifndef HB_NDEBUG
     unsigned int end = start + count;
     assert (end <= 8);
-    unsigned int bits = (1<<end) - (1<<start);
+    unsigned int bits = (1u<<end) - (1u<<start);
     assert (bits == (allocated_var_bits & bits));
 #endif
   }