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      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 #ifndef HB_SHAPER_PRIVATE_HH
     28 #define HB_SHAPER_PRIVATE_HH
     29 
     30 #include "hb-private.hh"
     31 
     32 typedef hb_bool_t hb_shape_func_t (hb_shape_plan_t    *shape_plan,
     33 				   hb_font_t          *font,
     34 				   hb_buffer_t        *buffer,
     35 				   const hb_feature_t *features,
     36 				   unsigned int        num_features);
     37 
     38 #define HB_SHAPER_IMPLEMENT(name) \
     39 	extern "C" HB_INTERNAL hb_shape_func_t _hb_##name##_shape;
     40 #include "hb-shaper-list.hh"
     41 #undef HB_SHAPER_IMPLEMENT
     42 
     43 struct hb_shaper_pair_t {
     44   char name[16];
     45   hb_shape_func_t *func;
     46 };
     47 
     48 HB_INTERNAL const hb_shaper_pair_t *
     49 _hb_shapers_get (void);
     50 
     51 
     52 /* For embedding in face / font / ... */
     53 struct hb_shaper_data_t {
     54 #define HB_SHAPER_IMPLEMENT(shaper) void *shaper;
     55 #include "hb-shaper-list.hh"
     56 #undef HB_SHAPER_IMPLEMENT
     57 };
     58 
     59 #define HB_SHAPERS_COUNT (sizeof (hb_shaper_data_t) / sizeof (void *))
     60 
     61 /* Means: succeeded, but don't need to keep any data. */
     62 #define HB_SHAPER_DATA_SUCCEEDED ((void *) +1)
     63 
     64 /* Means: tried but failed to create. */
     65 #define HB_SHAPER_DATA_INVALID ((void *) -1)
     66 #define HB_SHAPER_DATA_IS_INVALID(data) ((void *) (data) == HB_SHAPER_DATA_INVALID)
     67 
     68 #define HB_SHAPER_DATA_TYPE_NAME(shaper, object)	hb_##shaper##_shaper_##object##_data_t
     69 #define HB_SHAPER_DATA_TYPE(shaper, object)		struct HB_SHAPER_DATA_TYPE_NAME(shaper, object)
     70 #define HB_SHAPER_DATA_INSTANCE(shaper, object, instance)	(* (HB_SHAPER_DATA_TYPE(shaper, object) **) &(instance)->shaper_data.shaper)
     71 #define HB_SHAPER_DATA(shaper, object)			HB_SHAPER_DATA_INSTANCE(shaper, object, object)
     72 #define HB_SHAPER_DATA_CREATE_FUNC(shaper, object)	_hb_##shaper##_shaper_##object##_data_create
     73 #define HB_SHAPER_DATA_DESTROY_FUNC(shaper, object)	_hb_##shaper##_shaper_##object##_data_destroy
     74 #define HB_SHAPER_DATA_ENSURE_FUNC(shaper, object)	hb_##shaper##_shaper_##object##_data_ensure
     75 
     76 #define HB_SHAPER_DATA_PROTOTYPE(shaper, object) \
     77 	HB_SHAPER_DATA_TYPE (shaper, object); /* Type forward declaration. */ \
     78 	extern "C" HB_INTERNAL HB_SHAPER_DATA_TYPE (shaper, object) * \
     79 	HB_SHAPER_DATA_CREATE_FUNC (shaper, object) (hb_##object##_t *object HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS); \
     80 	extern "C" HB_INTERNAL void \
     81 	HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (HB_SHAPER_DATA_TYPE (shaper, object) *data); \
     82 	extern "C" HB_INTERNAL bool \
     83 	HB_SHAPER_DATA_ENSURE_FUNC (shaper, object) (hb_##object##_t *object)
     84 
     85 #define HB_SHAPER_DATA_DESTROY(shaper, object) \
     86     if (HB_SHAPER_DATA_TYPE (shaper, object) *data = HB_SHAPER_DATA (shaper, object)) \
     87       if (data != HB_SHAPER_DATA_INVALID && data != HB_SHAPER_DATA_SUCCEEDED) \
     88         HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (data);
     89 
     90 #define HB_SHAPER_DATA_ENSURE_DEFINE(shaper, object) \
     91 	HB_SHAPER_DATA_ENSURE_DEFINE_WITH_CONDITION(shaper, object, true)
     92 
     93 #define HB_SHAPER_DATA_ENSURE_DEFINE_WITH_CONDITION(shaper, object, condition) \
     94 bool \
     95 HB_SHAPER_DATA_ENSURE_FUNC(shaper, object) (hb_##object##_t *object) \
     96 {\
     97   retry: \
     98   HB_SHAPER_DATA_TYPE (shaper, object) *data = (HB_SHAPER_DATA_TYPE (shaper, object) *) hb_atomic_ptr_get (&HB_SHAPER_DATA (shaper, object)); \
     99   if (likely (data) && !(condition)) { \
    100     /* Drop and recreate. */ \
    101     /* If someone dropped it in the mean time, throw it away and don't touch it. \
    102      * Otherwise, destruct it. */ \
    103     if (hb_atomic_ptr_cmpexch (&HB_SHAPER_DATA (shaper, object), data, nullptr)) { \
    104       HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (data); \
    105     } \
    106     goto retry; \
    107   } \
    108   if (unlikely (!data)) { \
    109     data = HB_SHAPER_DATA_CREATE_FUNC (shaper, object) (object); \
    110     if (unlikely (!data)) \
    111       data = (HB_SHAPER_DATA_TYPE (shaper, object) *) HB_SHAPER_DATA_INVALID; \
    112     if (!hb_atomic_ptr_cmpexch (&HB_SHAPER_DATA (shaper, object), nullptr, data)) { \
    113       if (data && \
    114 	  data != HB_SHAPER_DATA_INVALID && \
    115 	  data != HB_SHAPER_DATA_SUCCEEDED) \
    116 	HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (data); \
    117       goto retry; \
    118     } \
    119   } \
    120   return data != nullptr && !HB_SHAPER_DATA_IS_INVALID (data); \
    121 }
    122 
    123 
    124 #endif /* HB_SHAPER_PRIVATE_HH */
    125