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_HH
28#define HB_SHAPER_HH
29
30#include "hb.hh"
31
32typedef 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
43struct hb_shaper_pair_t {
44 char name[16];
45 hb_shape_func_t *func;
46};
47
48HB_INTERNAL const hb_shaper_pair_t *
49_hb_shapers_get (void);
50
51
52/* Means: succeeded, but don't need to keep any data. */
53#define HB_SHAPER_DATA_SUCCEEDED ((void *) +1)
54/* Means: tried but failed to create. */
55#define HB_SHAPER_DATA_INVALID ((void *) -1)
56
57#define HB_SHAPER_DATA_TYPE_NAME(shaper, object) hb_##shaper##_##object##_data_t
58#define HB_SHAPER_DATA_TYPE(shaper, object) struct HB_SHAPER_DATA_TYPE_NAME(shaper, object)
59#define HB_SHAPER_DATA_INSTANCE(shaper, object, instance) (* reinterpret_cast<hb_atomic_ptr_t<HB_SHAPER_DATA_TYPE(shaper, object) *> *> (&(instance)->shaper_data.shaper))
60#define HB_SHAPER_DATA(shaper, object) HB_SHAPER_DATA_INSTANCE(shaper, object, object)
61#define HB_SHAPER_DATA_CREATE_FUNC(shaper, object) _hb_##shaper##_shaper_##object##_data_create
62#define HB_SHAPER_DATA_DESTROY_FUNC(shaper, object) _hb_##shaper##_shaper_##object##_data_destroy
63#define HB_SHAPER_DATA_ENSURE_FUNC(shaper, object) hb_##shaper##_shaper_##object##_data_ensure
64
65#define HB_SHAPER_DATA_PROTOTYPE(shaper, object) \
66 HB_SHAPER_DATA_TYPE (shaper, object); /* Type forward declaration. */ \
67 extern "C" HB_INTERNAL HB_SHAPER_DATA_TYPE (shaper, object) * \
68 HB_SHAPER_DATA_CREATE_FUNC (shaper, object) (hb_##object##_t *object HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS); \
69 extern "C" HB_INTERNAL void \
70 HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (HB_SHAPER_DATA_TYPE (shaper, object) *data); \
71 extern "C" HB_INTERNAL bool \
72 HB_SHAPER_DATA_ENSURE_FUNC (shaper, object) (hb_##object##_t *object)
73
74#define HB_SHAPER_DATA_DESTROY(shaper, object) \
75 if (HB_SHAPER_DATA_TYPE (shaper, object) *data = HB_SHAPER_DATA (shaper, object).get ()) \
76 if (data != HB_SHAPER_DATA_INVALID && data != HB_SHAPER_DATA_SUCCEEDED) \
77 HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (data);
78
79#define HB_SHAPER_DATA_ENSURE_DEFINE(shaper, object) \
80 HB_SHAPER_DATA_ENSURE_DEFINE_WITH_CONDITION(shaper, object, true)
81
82#define HB_SHAPER_DATA_ENSURE_DEFINE_WITH_CONDITION(shaper, object, condition) \
83bool \
84HB_SHAPER_DATA_ENSURE_FUNC(shaper, object) (hb_##object##_t *object) \
85{\
86 retry: \
87 HB_SHAPER_DATA_TYPE (shaper, object) *data = HB_SHAPER_DATA (shaper, object).get (); \
88 if (likely (data) && !(condition)) { \
89 /* XXX-MT-bug \
90 * Note that evaluating condition above can be dangerous if another thread \
91 * got here first and destructed data. That's, as always, bad use pattern. \
92 * If you modify the font (change font size), other threads must not be \
93 * using it at the same time. However, since this check is delayed to \
94 * when one actually tries to shape something, this is a XXX race condition \
95 * (and the only know we have that I know of) right now. Ie. you modify the \
96 * font size in one thread, then (supposedly safely) try to use it from two \
97 * or more threads and BOOM! I'm not sure how to fix this. We want RCU. \
98 * Maybe when it doesn't matter when we finally implement AAT shaping, as
99 * this (condition) is currently only used by hb-coretext. */ \
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 (likely (HB_SHAPER_DATA (shaper, object).cmpexch (data, nullptr))) \
104 { \
105 HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (data); \
106 } \
107 goto retry; \
108 } \
109 if (unlikely (!data)) { \
110 data = HB_SHAPER_DATA_CREATE_FUNC (shaper, object) (object); \
111 if (unlikely (!data)) \
112 data = (HB_SHAPER_DATA_TYPE (shaper, object) *) HB_SHAPER_DATA_INVALID; \
113 if (unlikely (!HB_SHAPER_DATA (shaper, object).cmpexch (nullptr, data))) { \
114 if (data && \
115 data != HB_SHAPER_DATA_INVALID && \
116 data != HB_SHAPER_DATA_SUCCEEDED) \
117 HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (data); \
118 goto retry; \
119 } \
120 } \
121 return data != nullptr && (void *) data != HB_SHAPER_DATA_INVALID; \
122}
123
124
125/* For embedding in face / font / ... */
126struct hb_shaper_data_t {
127#define HB_SHAPER_IMPLEMENT(shaper) hb_atomic_ptr_t<void *> shaper;
128#include "hb-shaper-list.hh"
129#undef HB_SHAPER_IMPLEMENT
130};
131#define HB_SHAPERS_COUNT (sizeof (hb_shaper_data_t) / sizeof (void *))
132
133
134#endif /* HB_SHAPER_HH */
135