1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/harfbuzz/src/hb-shaper.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,109 @@
1.4 +/*
1.5 + * Copyright © 2012 Google, Inc.
1.6 + *
1.7 + * This is part of HarfBuzz, a text shaping library.
1.8 + *
1.9 + * Permission is hereby granted, without written agreement and without
1.10 + * license or royalty fees, to use, copy, modify, and distribute this
1.11 + * software and its documentation for any purpose, provided that the
1.12 + * above copyright notice and the following two paragraphs appear in
1.13 + * all copies of this software.
1.14 + *
1.15 + * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
1.16 + * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
1.17 + * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
1.18 + * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
1.19 + * DAMAGE.
1.20 + *
1.21 + * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
1.22 + * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
1.23 + * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
1.24 + * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
1.25 + * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
1.26 + *
1.27 + * Google Author(s): Behdad Esfahbod
1.28 + */
1.29 +
1.30 +#include "hb-private.hh"
1.31 +#include "hb-shaper-private.hh"
1.32 +#include "hb-atomic-private.hh"
1.33 +
1.34 +
1.35 +static const hb_shaper_pair_t all_shapers[] = {
1.36 +#define HB_SHAPER_IMPLEMENT(name) {#name, _hb_##name##_shape},
1.37 +#include "hb-shaper-list.hh"
1.38 +#undef HB_SHAPER_IMPLEMENT
1.39 +};
1.40 +
1.41 +
1.42 +/* Thread-safe, lock-free, shapers */
1.43 +
1.44 +static const hb_shaper_pair_t *static_shapers;
1.45 +
1.46 +static inline
1.47 +void free_static_shapers (void)
1.48 +{
1.49 + if (unlikely (static_shapers != all_shapers))
1.50 + free ((void *) static_shapers);
1.51 +}
1.52 +
1.53 +const hb_shaper_pair_t *
1.54 +_hb_shapers_get (void)
1.55 +{
1.56 +retry:
1.57 + hb_shaper_pair_t *shapers = (hb_shaper_pair_t *) hb_atomic_ptr_get (&static_shapers);
1.58 +
1.59 + if (unlikely (!shapers))
1.60 + {
1.61 + char *env = getenv ("HB_SHAPER_LIST");
1.62 + if (!env || !*env) {
1.63 + (void) hb_atomic_ptr_cmpexch (&static_shapers, NULL, &all_shapers[0]);
1.64 + return (const hb_shaper_pair_t *) all_shapers;
1.65 + }
1.66 +
1.67 + /* Not found; allocate one. */
1.68 + shapers = (hb_shaper_pair_t *) malloc (sizeof (all_shapers));
1.69 + if (unlikely (!shapers)) {
1.70 + (void) hb_atomic_ptr_cmpexch (&static_shapers, NULL, &all_shapers[0]);
1.71 + return (const hb_shaper_pair_t *) all_shapers;
1.72 + }
1.73 +
1.74 + memcpy (shapers, all_shapers, sizeof (all_shapers));
1.75 +
1.76 + /* Reorder shaper list to prefer requested shapers. */
1.77 + unsigned int i = 0;
1.78 + char *end, *p = env;
1.79 + for (;;) {
1.80 + end = strchr (p, ',');
1.81 + if (!end)
1.82 + end = p + strlen (p);
1.83 +
1.84 + for (unsigned int j = i; j < ARRAY_LENGTH (all_shapers); j++)
1.85 + if (end - p == (int) strlen (shapers[j].name) &&
1.86 + 0 == strncmp (shapers[j].name, p, end - p))
1.87 + {
1.88 + /* Reorder this shaper to position i */
1.89 + struct hb_shaper_pair_t t = shapers[j];
1.90 + memmove (&shapers[i + 1], &shapers[i], sizeof (shapers[i]) * (j - i));
1.91 + shapers[i] = t;
1.92 + i++;
1.93 + }
1.94 +
1.95 + if (!*end)
1.96 + break;
1.97 + else
1.98 + p = end + 1;
1.99 + }
1.100 +
1.101 + if (!hb_atomic_ptr_cmpexch (&static_shapers, NULL, shapers)) {
1.102 + free (shapers);
1.103 + goto retry;
1.104 + }
1.105 +
1.106 +#ifdef HAVE_ATEXIT
1.107 + atexit (free_static_shapers); /* First person registers atexit() callback. */
1.108 +#endif
1.109 + }
1.110 +
1.111 + return shapers;
1.112 +}
