112 lines
3.1 KiB
C++
112 lines
3.1 KiB
C++
/*
|
|
* 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
|
|
*/
|
|
|
|
#include "hb-private.hh"
|
|
#include "hb-shaper-private.hh"
|
|
#include "hb-atomic-private.hh"
|
|
|
|
|
|
static const hb_shaper_pair_t all_shapers[] = {
|
|
#define HB_SHAPER_IMPLEMENT(name) {#name, _hb_##name##_shape},
|
|
#include "hb-shaper-list.hh"
|
|
#undef HB_SHAPER_IMPLEMENT
|
|
};
|
|
|
|
|
|
/* Thread-safe, lock-free, shapers */
|
|
|
|
static const hb_shaper_pair_t *static_shapers;
|
|
|
|
#ifdef HB_USE_ATEXIT
|
|
static
|
|
void free_static_shapers (void)
|
|
{
|
|
if (unlikely (static_shapers != all_shapers))
|
|
free ((void *) static_shapers);
|
|
}
|
|
#endif
|
|
|
|
const hb_shaper_pair_t *
|
|
_hb_shapers_get (void)
|
|
{
|
|
retry:
|
|
hb_shaper_pair_t *shapers = (hb_shaper_pair_t *) hb_atomic_ptr_get (&static_shapers);
|
|
|
|
if (unlikely (!shapers))
|
|
{
|
|
char *env = getenv ("HB_SHAPER_LIST");
|
|
if (!env || !*env) {
|
|
(void) hb_atomic_ptr_cmpexch (&static_shapers, NULL, &all_shapers[0]);
|
|
return (const hb_shaper_pair_t *) all_shapers;
|
|
}
|
|
|
|
/* Not found; allocate one. */
|
|
shapers = (hb_shaper_pair_t *) malloc (sizeof (all_shapers));
|
|
if (unlikely (!shapers)) {
|
|
(void) hb_atomic_ptr_cmpexch (&static_shapers, NULL, &all_shapers[0]);
|
|
return (const hb_shaper_pair_t *) all_shapers;
|
|
}
|
|
|
|
memcpy (shapers, all_shapers, sizeof (all_shapers));
|
|
|
|
/* Reorder shaper list to prefer requested shapers. */
|
|
unsigned int i = 0;
|
|
char *end, *p = env;
|
|
for (;;) {
|
|
end = strchr (p, ',');
|
|
if (!end)
|
|
end = p + strlen (p);
|
|
|
|
for (unsigned int j = i; j < ARRAY_LENGTH (all_shapers); j++)
|
|
if (end - p == (int) strlen (shapers[j].name) &&
|
|
0 == strncmp (shapers[j].name, p, end - p))
|
|
{
|
|
/* Reorder this shaper to position i */
|
|
struct hb_shaper_pair_t t = shapers[j];
|
|
memmove (&shapers[i + 1], &shapers[i], sizeof (shapers[i]) * (j - i));
|
|
shapers[i] = t;
|
|
i++;
|
|
}
|
|
|
|
if (!*end)
|
|
break;
|
|
else
|
|
p = end + 1;
|
|
}
|
|
|
|
if (!hb_atomic_ptr_cmpexch (&static_shapers, NULL, shapers)) {
|
|
free (shapers);
|
|
goto retry;
|
|
}
|
|
|
|
#ifdef HB_USE_ATEXIT
|
|
atexit (free_static_shapers); /* First person registers atexit() callback. */
|
|
#endif
|
|
}
|
|
|
|
return shapers;
|
|
}
|