/*

 * 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_PRIVATE_HH

#define HB_CACHE_PRIVATE_HH

#include "hb-private.hh"

/* Implements a lock-free cache for int->int functions. */

template <unsigned int key_bits, unsigned int value_bits, unsigned int cache_bits>

struct hb_cache_t

{

  ASSERT_STATIC (key_bits >= cache_bits);

  ASSERT_STATIC (key_bits + value_bits - cache_bits < 8 * sizeof (unsigned int));

  inline void clear (void)

  {

    memset (values, 255, sizeof (values));

  }

  inline bool get (unsigned int key, unsigned int *value)

  {

    unsigned int k = key & ((1u<

    unsigned int v = values[k];

    if ((v >> value_bits) != (key >> cache_bits))

      return false;

    *value = v & ((1u<

    return true;

  }

  inline bool set (unsigned int key, unsigned int value)

  {

    if (unlikely ((key >> key_bits) || (value >> value_bits)))

      return false; /* Overflows */

    unsigned int k = key & ((1u<

    unsigned int v = ((key>>cache_bits)<

    values[k] = v;

    return true;

  }

  private:

  unsigned int values[1u<

};

typedef hb_cache_t<21, 16, 8> hb_cmap_cache_t;

typedef hb_cache_t<16, 24, 8> hb_advance_cache_t;

#endif /* HB_CACHE_PRIVATE_HH */