tor-browser

The Tor Browser
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hb-shaper.cc (2985B)

      1 /*
      2 * Copyright © 2012  Google, Inc.
      3 *
      4 *  This is part of HarfBuzz, a text shaping library.
      5 *
      6 * Permission is hereby granted, without written agreement and without
      7 * license or royalty fees, to use, copy, modify, and distribute this
      8 * software and its documentation for any purpose, provided that the
      9 * above copyright notice and the following two paragraphs appear in
     10 * all copies of this software.
     11 *
     12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
     13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
     14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
     15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
     16 * DAMAGE.
     17 *
     18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
     19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
     20 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
     21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
     22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
     23 *
     24 * Google Author(s): Behdad Esfahbod
     25 */
     26 
     27 #include "hb.hh"
     28 #include "hb-shaper.hh"
     29 #include "hb-machinery.hh"
     30 
     31 
     32 static const hb_shaper_entry_t _hb_all_shapers[] = {
     33 #define HB_SHAPER_IMPLEMENT(name) {#name, _hb_##name##_shape},
     34 #include "hb-shaper-list.hh"
     35 #undef HB_SHAPER_IMPLEMENT
     36 };
     37 #ifndef HB_NO_SHAPER
     38 static_assert (0 != ARRAY_LENGTH_CONST (_hb_all_shapers), "No shaper enabled.");
     39 #endif
     40 
     41 static inline void free_static_shapers ();
     42 
     43 static struct hb_shapers_lazy_loader_t : hb_lazy_loader_t<hb_shaper_entry_t,
     44 						  hb_shapers_lazy_loader_t>
     45 {
     46  static hb_shaper_entry_t *create ()
     47  {
     48    char *env = getenv ("HB_SHAPER_LIST");
     49    if (!env || !*env)
     50      return nullptr;
     51 
     52    hb_shaper_entry_t *shapers = (hb_shaper_entry_t *) hb_calloc (1, sizeof (_hb_all_shapers));
     53    if (unlikely (!shapers))
     54      return nullptr;
     55 
     56    hb_memcpy (shapers, _hb_all_shapers, sizeof (_hb_all_shapers));
     57 
     58     /* Reorder shaper list to prefer requested shapers. */
     59    unsigned int i = 0;
     60    char *end, *p = env;
     61    for (;;)
     62    {
     63      end = strchr (p, ',');
     64      if (!end)
     65 end = p + strlen (p);
     66 
     67      for (unsigned int j = i; j < ARRAY_LENGTH_CONST (_hb_all_shapers); j++)
     68 if (end - p == (int) strlen (shapers[j].name) &&
     69     0 == strncmp (shapers[j].name, p, end - p))
     70 {
     71   /* Reorder this shaper to position i */
     72  struct hb_shaper_entry_t t = shapers[j];
     73  memmove (&shapers[i + 1], &shapers[i], sizeof (shapers[i]) * (j - i));
     74  shapers[i] = t;
     75  i++;
     76 }
     77 
     78      if (!*end)
     79 break;
     80      else
     81 p = end + 1;
     82    }
     83 
     84    hb_atexit (free_static_shapers);
     85 
     86    return shapers;
     87  }
     88  static void destroy (hb_shaper_entry_t *p) { hb_free (p); }
     89  static const hb_shaper_entry_t *get_null ()      { return _hb_all_shapers; }
     90 } static_shapers;
     91 
     92 static inline
     93 void free_static_shapers ()
     94 {
     95  static_shapers.free_instance ();
     96 }
     97 
     98 const hb_shaper_entry_t *
     99 _hb_shapers_get ()
    100 {
    101  return static_shapers.get_unconst ();
    102 }