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comparison mupdf-source/thirdparty/harfbuzz/src/hb-machinery.hh @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 /*
2 * Copyright © 2007,2008,2009,2010 Red Hat, Inc.
3 * Copyright © 2012,2018 Google, Inc.
4 *
5 * This is part of HarfBuzz, a text shaping library.
6 *
7 * Permission is hereby granted, without written agreement and without
8 * license or royalty fees, to use, copy, modify, and distribute this
9 * software and its documentation for any purpose, provided that the
10 * above copyright notice and the following two paragraphs appear in
11 * all copies of this software.
12 *
13 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17 * DAMAGE.
18 *
19 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
22 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24 *
25 * Red Hat Author(s): Behdad Esfahbod
26 * Google Author(s): Behdad Esfahbod
27 */
28
29 #ifndef HB_MACHINERY_HH
30 #define HB_MACHINERY_HH
31
32 #include "hb.hh"
33 #include "hb-blob.hh"
34
35 #include "hb-dispatch.hh"
36 #include "hb-sanitize.hh"
37 #include "hb-serialize.hh"
38
39
40 /*
41 * Casts
42 */
43
44 /* StructAtOffset<T>(P,Ofs) returns the struct T& that is placed at memory
45 * location pointed to by P plus Ofs bytes. */
46 template<typename Type>
47 static inline const Type& StructAtOffset(const void *P, unsigned int offset)
48 { return * reinterpret_cast<const Type*> ((const char *) P + offset); }
49 template<typename Type>
50 static inline Type& StructAtOffset(void *P, unsigned int offset)
51 { return * reinterpret_cast<Type*> ((char *) P + offset); }
52 template<typename Type>
53 static inline const Type& StructAtOffsetUnaligned(const void *P, unsigned int offset)
54 {
55 #pragma GCC diagnostic push
56 #pragma GCC diagnostic ignored "-Wcast-align"
57 return * reinterpret_cast<const Type*> ((const char *) P + offset);
58 #pragma GCC diagnostic pop
59 }
60 template<typename Type>
61 static inline Type& StructAtOffsetUnaligned(void *P, unsigned int offset)
62 {
63 #pragma GCC diagnostic push
64 #pragma GCC diagnostic ignored "-Wcast-align"
65 return * reinterpret_cast<Type*> ((char *) P + offset);
66 #pragma GCC diagnostic pop
67 }
68
69 /* StructAfter<T>(X) returns the struct T& that is placed after X.
70 * Works with X of variable size also. X must implement get_size() */
71 template<typename Type, typename TObject>
72 static inline const Type& StructAfter(const TObject &X)
73 { return StructAtOffset<Type>(&X, X.get_size()); }
74 template<typename Type, typename TObject>
75 static inline Type& StructAfter(TObject &X)
76 { return StructAtOffset<Type>(&X, X.get_size()); }
77
78
79 /*
80 * Size checking
81 */
82
83 /* Size signifying variable-sized array */
84 #ifndef HB_VAR_ARRAY
85 #define HB_VAR_ARRAY 1
86 #endif
87
88 /* Check _assertion in a method environment */
89 #define _DEFINE_INSTANCE_ASSERTION1(_line, _assertion) \
90 void _instance_assertion_on_line_##_line () const \
91 { static_assert ((_assertion), ""); }
92 # define _DEFINE_INSTANCE_ASSERTION0(_line, _assertion) _DEFINE_INSTANCE_ASSERTION1 (_line, _assertion)
93 # define DEFINE_INSTANCE_ASSERTION(_assertion) _DEFINE_INSTANCE_ASSERTION0 (__LINE__, _assertion)
94
95 /* Check that _code compiles in a method environment */
96 #define _DEFINE_COMPILES_ASSERTION1(_line, _code) \
97 void _compiles_assertion_on_line_##_line () const \
98 { _code; }
99 # define _DEFINE_COMPILES_ASSERTION0(_line, _code) _DEFINE_COMPILES_ASSERTION1 (_line, _code)
100 # define DEFINE_COMPILES_ASSERTION(_code) _DEFINE_COMPILES_ASSERTION0 (__LINE__, _code)
101
102
103 #define DEFINE_SIZE_STATIC(size) \
104 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size)) \
105 unsigned int get_size () const { return (size); } \
106 static constexpr unsigned null_size = (size); \
107 static constexpr unsigned min_size = (size); \
108 static constexpr unsigned static_size = (size)
109
110 #define DEFINE_SIZE_UNION(size, _member) \
111 DEFINE_COMPILES_ASSERTION ((void) this->u._member.static_size) \
112 DEFINE_INSTANCE_ASSERTION (sizeof(this->u._member) == (size)) \
113 static constexpr unsigned null_size = (size); \
114 static constexpr unsigned min_size = (size)
115
116 #define DEFINE_SIZE_MIN(size) \
117 DEFINE_INSTANCE_ASSERTION (sizeof (*this) >= (size)) \
118 static constexpr unsigned null_size = (size); \
119 static constexpr unsigned min_size = (size)
120
121 #define DEFINE_SIZE_UNBOUNDED(size) \
122 DEFINE_INSTANCE_ASSERTION (sizeof (*this) >= (size)) \
123 static constexpr unsigned min_size = (size)
124
125 #define DEFINE_SIZE_ARRAY(size, array) \
126 DEFINE_COMPILES_ASSERTION ((void) (array)[0].static_size) \
127 DEFINE_INSTANCE_ASSERTION (sizeof (*this) == (size) + (HB_VAR_ARRAY+0) * sizeof ((array)[0])) \
128 static constexpr unsigned null_size = (size); \
129 static constexpr unsigned min_size = (size)
130
131 #define DEFINE_SIZE_ARRAY_SIZED(size, array) \
132 unsigned int get_size () const { return (size - (array).min_size + (array).get_size ()); } \
133 DEFINE_SIZE_ARRAY(size, array)
134
135
136
137 /*
138 * Lazy loaders.
139 *
140 * The lazy-loaders are thread-safe pointer-like objects that create their
141 * instead on-demand. They also support access to a "data" object that is
142 * necessary for creating their instance. The data object, if specified,
143 * is accessed via pointer math, located at a location before the position
144 * of the loader itself. This avoids having to store a pointer to data
145 * for every lazy-loader. Multiple lazy-loaders can access the same data.
146 */
147
148 template <typename Data, unsigned int WheresData>
149 struct hb_data_wrapper_t
150 {
151 static_assert (WheresData > 0, "");
152
153 Data * get_data () const
154 { return *(((Data **) (void *) this) - WheresData); }
155
156 bool is_inert () const { return !get_data (); }
157
158 template <typename Stored, typename Subclass>
159 Stored * call_create () const { return Subclass::create (get_data ()); }
160 };
161 template <>
162 struct hb_data_wrapper_t<void, 0>
163 {
164 bool is_inert () const { return false; }
165
166 template <typename Stored, typename Funcs>
167 Stored * call_create () const { return Funcs::create (); }
168 };
169
170 template <typename T1, typename T2> struct hb_non_void_t { typedef T1 value; };
171 template <typename T2> struct hb_non_void_t<void, T2> { typedef T2 value; };
172
173 template <typename Returned,
174 typename Subclass = void,
175 typename Data = void,
176 unsigned int WheresData = 0,
177 typename Stored = Returned>
178 struct hb_lazy_loader_t : hb_data_wrapper_t<Data, WheresData>
179 {
180 typedef typename hb_non_void_t<Subclass,
181 hb_lazy_loader_t<Returned,Subclass,Data,WheresData,Stored>
182 >::value Funcs;
183
184 void init0 () {} /* Init, when memory is already set to 0. No-op for us. */
185 void init () { instance.set_relaxed (nullptr); }
186 void fini () { do_destroy (instance.get_acquire ()); init (); }
187
188 void free_instance ()
189 {
190 retry:
191 Stored *p = instance.get_acquire ();
192 if (unlikely (p && !cmpexch (p, nullptr)))
193 goto retry;
194 do_destroy (p);
195 }
196
197 static void do_destroy (Stored *p)
198 {
199 if (p && p != const_cast<Stored *> (Funcs::get_null ()))
200 Funcs::destroy (p);
201 }
202
203 const Returned * operator -> () const { return get (); }
204 template <typename U = Returned, hb_enable_if (!hb_is_same (U, void))>
205 const U & operator * () const { return *get (); }
206 explicit operator bool () const
207 { return get_stored () != Funcs::get_null (); }
208 template <typename C> operator const C * () const { return get (); }
209
210 Stored * get_stored () const
211 {
212 retry:
213 Stored *p = this->instance.get_acquire ();
214 if (unlikely (!p))
215 {
216 if (unlikely (this->is_inert ()))
217 return const_cast<Stored *> (Funcs::get_null ());
218
219 p = this->template call_create<Stored, Funcs> ();
220 if (unlikely (!p))
221 p = const_cast<Stored *> (Funcs::get_null ());
222
223 if (unlikely (!cmpexch (nullptr, p)))
224 {
225 do_destroy (p);
226 goto retry;
227 }
228 }
229 return p;
230 }
231 Stored * get_stored_relaxed () const
232 {
233 return this->instance.get_relaxed ();
234 }
235
236 bool cmpexch (Stored *current, Stored *value) const
237 {
238 /* This function can only be safely called directly if no
239 * other thread is accessing. */
240 return this->instance.cmpexch (current, value);
241 }
242
243 const Returned * get () const { return Funcs::convert (get_stored ()); }
244 const Returned * get_relaxed () const { return Funcs::convert (get_stored_relaxed ()); }
245 Returned * get_unconst () const { return const_cast<Returned *> (Funcs::convert (get_stored ())); }
246
247 /* To be possibly overloaded by subclasses. */
248 static Returned* convert (Stored *p) { return p; }
249
250 /* By default null/init/fini the object. */
251 static const Stored* get_null () { return &Null (Stored); }
252 static Stored *create (Data *data)
253 {
254 Stored *p = (Stored *) hb_calloc (1, sizeof (Stored));
255 if (likely (p))
256 p = new (p) Stored (data);
257 return p;
258 }
259 static Stored *create ()
260 {
261 Stored *p = (Stored *) hb_calloc (1, sizeof (Stored));
262 if (likely (p))
263 p = new (p) Stored ();
264 return p;
265 }
266 static void destroy (Stored *p)
267 {
268 p->~Stored ();
269 hb_free (p);
270 }
271
272 private:
273 /* Must only have one pointer. */
274 hb_atomic_ptr_t<Stored *> instance;
275 };
276
277 /* Specializations. */
278
279 template <typename T, unsigned int WheresFace>
280 struct hb_face_lazy_loader_t : hb_lazy_loader_t<T,
281 hb_face_lazy_loader_t<T, WheresFace>,
282 hb_face_t, WheresFace> {};
283
284 template <typename T, unsigned int WheresFace, bool core=false>
285 struct hb_table_lazy_loader_t : hb_lazy_loader_t<T,
286 hb_table_lazy_loader_t<T, WheresFace, core>,
287 hb_face_t, WheresFace,
288 hb_blob_t>
289 {
290 static hb_blob_t *create (hb_face_t *face)
291 {
292 auto c = hb_sanitize_context_t ();
293 if (core)
294 c.set_num_glyphs (0); // So we don't recurse ad infinitum, or doesn't need num_glyphs
295 return c.reference_table<T> (face);
296 }
297 static void destroy (hb_blob_t *p) { hb_blob_destroy (p); }
298
299 static const hb_blob_t *get_null ()
300 { return hb_blob_get_empty (); }
301
302 static const T* convert (const hb_blob_t *blob)
303 { return blob->as<T> (); }
304
305 hb_blob_t* get_blob () const { return this->get_stored (); }
306 };
307
308 template <typename Subclass>
309 struct hb_font_funcs_lazy_loader_t : hb_lazy_loader_t<hb_font_funcs_t, Subclass>
310 {
311 static void destroy (hb_font_funcs_t *p)
312 { hb_font_funcs_destroy (p); }
313 static const hb_font_funcs_t *get_null ()
314 { return hb_font_funcs_get_empty (); }
315 };
316 template <typename Subclass>
317 struct hb_unicode_funcs_lazy_loader_t : hb_lazy_loader_t<hb_unicode_funcs_t, Subclass>
318 {
319 static void destroy (hb_unicode_funcs_t *p)
320 { hb_unicode_funcs_destroy (p); }
321 static const hb_unicode_funcs_t *get_null ()
322 { return hb_unicode_funcs_get_empty (); }
323 };
324
325
326 #endif /* HB_MACHINERY_HH */