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diff --git a/gfx/harfbuzz/src/hb-cache.hh b/gfx/harfbuzz/src/hb-cache.hh
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+/*
+ * Copyright © 2012  Google, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#ifndef HB_CACHE_HH
+#define HB_CACHE_HH
+
+#include "hb.hh"
+
+
+/* Implements a lockfree cache for int->int functions.
+ *
+ * The cache is a fixed-size array of 16-bit or 32-bit integers.
+ * The key is split into two parts: the cache index and the rest.
+ *
+ * The cache index is used to index into the array.  The rest is used
+ * to store the key and the value.
+ *
+ * The value is stored in the least significant bits of the integer.
+ * The key is stored in the most significant bits of the integer.
+ * The key is shifted by cache_bits to the left to make room for the
+ * value.
+ */
+
+template <unsigned int key_bits=16,
+	 unsigned int value_bits=8 + 32 - key_bits,
+	 unsigned int cache_bits=8,
+	 bool thread_safe=true>
+struct hb_cache_t
+{
+  using item_t = typename std::conditional<thread_safe,
+					   typename std::conditional<key_bits + value_bits - cache_bits <= 16,
+								     hb_atomic_short_t,
+								     hb_atomic_int_t>::type,
+					   typename std::conditional<key_bits + value_bits - cache_bits <= 16,
+								     short,
+								     int>::type
+					  >::type;
+
+  static_assert ((key_bits >= cache_bits), "");
+  static_assert ((key_bits + value_bits <= cache_bits + 8 * sizeof (item_t)), "");
+
+  hb_cache_t () { init (); }
+
+  void init () { clear (); }
+
+  void clear ()
+  {
+    for (unsigned i = 0; i < ARRAY_LENGTH (values); i++)
+      values[i] = -1;
+  }
+
+  bool get (unsigned int key, unsigned int *value) const
+  {
+    unsigned int k = key & ((1u<<cache_bits)-1);
+    unsigned int v = values[k];
+    if ((key_bits + value_bits - cache_bits == 8 * sizeof (item_t) && v == (unsigned int) -1) ||
+	(v >> value_bits) != (key >> cache_bits))
+      return false;
+    *value = v & ((1u<<value_bits)-1);
+    return true;
+  }
+
+  bool set (unsigned int key, unsigned int value)
+  {
+    if (unlikely ((key >> key_bits) || (value >> value_bits)))
+      return false; /* Overflows */
+    unsigned int k = key & ((1u<<cache_bits)-1);
+    unsigned int v = ((key>>cache_bits)<<value_bits) | value;
+    values[k] = v;
+    return true;
+  }
+
+  private:
+  item_t values[1u<<cache_bits];
+};
+
+
+#endif /* HB_CACHE_HH */