1 /*
2 * Copyright © 2018 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_ARRAY_HH
28 #define HB_ARRAY_HH
29
30 #include "hb.hh"
31 #include "hb-algs.hh"
32 #include "hb-iter.hh"
33 #include "hb-null.hh"
34
35
36 template <typename Type>
37 struct hb_sorted_array_t;
38
39 template <typename Type>
40 struct hb_array_t : hb_iter_with_fallback_t<hb_array_t<Type>, Type&>
41 {
42 /*
43 * Constructors.
44 */
hb_array_thb_array_t45 hb_array_t () : arrayZ (nullptr), length (0), backwards_length (0) {}
hb_array_thb_array_t46 hb_array_t (Type *array_, unsigned int length_) : arrayZ (array_), length (length_), backwards_length (0) {}
47 template <unsigned int length_>
hb_array_thb_array_t48 hb_array_t (Type (&array_)[length_]) : arrayZ (array_), length (length_), backwards_length (0) {}
49
50 template <typename U,
51 hb_enable_if (hb_is_cr_convertible(U, Type))>
hb_array_thb_array_t52 hb_array_t (const hb_array_t<U> &o) :
53 hb_iter_with_fallback_t<hb_array_t, Type&> (),
54 arrayZ (o.arrayZ), length (o.length), backwards_length (o.backwards_length) {}
55 template <typename U,
56 hb_enable_if (hb_is_cr_convertible(U, Type))>
operator =hb_array_t57 hb_array_t& operator = (const hb_array_t<U> &o)
58 { arrayZ = o.arrayZ; length = o.length; backwards_length = o.backwards_length; return *this; }
59
60 /*
61 * Iterator implementation.
62 */
63 typedef Type& __item_t__;
64 static constexpr bool is_random_access_iterator = true;
__item_at__hb_array_t65 Type& __item_at__ (unsigned i) const
66 {
67 if (unlikely (i >= length)) return CrapOrNull (Type);
68 return arrayZ[i];
69 }
__forward__hb_array_t70 void __forward__ (unsigned n)
71 {
72 if (unlikely (n > length))
73 n = length;
74 length -= n;
75 backwards_length += n;
76 arrayZ += n;
77 }
__rewind__hb_array_t78 void __rewind__ (unsigned n)
79 {
80 if (unlikely (n > backwards_length))
81 n = backwards_length;
82 length += n;
83 backwards_length -= n;
84 arrayZ -= n;
85 }
__len__hb_array_t86 unsigned __len__ () const { return length; }
87 /* Ouch. The operator== compares the contents of the array. For range-based for loops,
88 * it's best if we can just compare arrayZ, though comparing contents is still fast,
89 * but also would require that Type has operator==. As such, we optimize this operator
90 * for range-based for loop and just compare arrayZ. No need to compare length, as we
91 * assume we're only compared to .end(). */
operator !=hb_array_t92 bool operator != (const hb_array_t& o) const
93 { return arrayZ != o.arrayZ; }
94
95 /* Extra operators.
96 */
operator &hb_array_t97 Type * operator & () const { return arrayZ; }
operator hb_array_t<const Type>hb_array_t98 operator hb_array_t<const Type> () { return hb_array_t<const Type> (arrayZ, length); }
operator T*hb_array_t99 template <typename T> operator T * () const { return arrayZ; }
100
101 HB_INTERNAL bool operator == (const hb_array_t &o) const;
102
hashhb_array_t103 uint32_t hash () const {
104 uint32_t current = 0;
105 for (unsigned int i = 0; i < this->length; i++) {
106 current = current * 31 + hb_hash (this->arrayZ[i]);
107 }
108 return current;
109 }
110
111 /*
112 * Compare, Sort, and Search.
113 */
114
115 /* Note: our compare is NOT lexicographic; it also does NOT call Type::cmp. */
cmphb_array_t116 int cmp (const hb_array_t &a) const
117 {
118 if (length != a.length)
119 return (int) a.length - (int) length;
120 return hb_memcmp (a.arrayZ, arrayZ, get_size ());
121 }
cmphb_array_t122 HB_INTERNAL static int cmp (const void *pa, const void *pb)
123 {
124 hb_array_t *a = (hb_array_t *) pa;
125 hb_array_t *b = (hb_array_t *) pb;
126 return b->cmp (*a);
127 }
128
129 template <typename T>
lsearchhb_array_t130 Type *lsearch (const T &x, Type *not_found = nullptr)
131 {
132 unsigned int count = length;
133 for (unsigned int i = 0; i < count; i++)
134 if (!this->arrayZ[i].cmp (x))
135 return &this->arrayZ[i];
136 return not_found;
137 }
138 template <typename T>
lsearchhb_array_t139 const Type *lsearch (const T &x, const Type *not_found = nullptr) const
140 {
141 unsigned int count = length;
142 for (unsigned int i = 0; i < count; i++)
143 if (!this->arrayZ[i].cmp (x))
144 return &this->arrayZ[i];
145 return not_found;
146 }
147
qsorthb_array_t148 hb_sorted_array_t<Type> qsort (int (*cmp_)(const void*, const void*))
149 {
150 if (likely (length))
151 hb_qsort (arrayZ, length, this->get_item_size (), cmp_);
152 return hb_sorted_array_t<Type> (*this);
153 }
qsorthb_array_t154 hb_sorted_array_t<Type> qsort ()
155 {
156 if (likely (length))
157 hb_qsort (arrayZ, length, this->get_item_size (), Type::cmp);
158 return hb_sorted_array_t<Type> (*this);
159 }
qsorthb_array_t160 void qsort (unsigned int start, unsigned int end)
161 {
162 end = hb_min (end, length);
163 assert (start <= end);
164 if (likely (start < end))
165 hb_qsort (arrayZ + start, end - start, this->get_item_size (), Type::cmp);
166 }
167
168 /*
169 * Other methods.
170 */
171
get_sizehb_array_t172 unsigned int get_size () const { return length * this->get_item_size (); }
173
174 /*
175 * Reverse the order of items in this array in the range [start, end).
176 */
reversehb_array_t177 void reverse (unsigned start = 0, unsigned end = -1)
178 {
179 start = hb_min (start, length);
180 end = hb_min (end, length);
181
182 if (end < start + 2)
183 return;
184
185 for (unsigned lhs = start, rhs = end - 1; lhs < rhs; lhs++, rhs--) {
186 Type temp = arrayZ[rhs];
187 arrayZ[rhs] = arrayZ[lhs];
188 arrayZ[lhs] = temp;
189 }
190 }
191
sub_arrayhb_array_t192 hb_array_t sub_array (unsigned int start_offset = 0, unsigned int *seg_count = nullptr /* IN/OUT */) const
193 {
194 if (!start_offset && !seg_count)
195 return *this;
196
197 unsigned int count = length;
198 if (unlikely (start_offset > count))
199 count = 0;
200 else
201 count -= start_offset;
202 if (seg_count)
203 count = *seg_count = hb_min (count, *seg_count);
204 return hb_array_t (arrayZ + start_offset, count);
205 }
sub_arrayhb_array_t206 hb_array_t sub_array (unsigned int start_offset, unsigned int seg_count) const
207 { return sub_array (start_offset, &seg_count); }
208
truncatehb_array_t209 hb_array_t truncate (unsigned length) const { return sub_array (0, length); }
210
211 template <typename T,
212 unsigned P = sizeof (Type),
213 hb_enable_if (P == 1)>
ashb_array_t214 const T *as () const
215 { return length < hb_null_size (T) ? &Null (T) : reinterpret_cast<const T *> (arrayZ); }
216
217 template <typename T,
218 unsigned P = sizeof (Type),
219 hb_enable_if (P == 1)>
check_rangehb_array_t220 bool check_range (const T *p, unsigned int size = T::static_size) const
221 {
222 return arrayZ <= ((const char *) p)
223 && ((const char *) p) <= arrayZ + length
224 && (unsigned int) (arrayZ + length - (const char *) p) >= size;
225 }
226
227 /* Only call if you allocated the underlying array using malloc() or similar. */
freehb_array_t228 void free ()
229 { ::free ((void *) arrayZ); arrayZ = nullptr; length = 0; }
230
231 template <typename hb_serialize_context_t>
copyhb_array_t232 hb_array_t copy (hb_serialize_context_t *c) const
233 {
234 TRACE_SERIALIZE (this);
235 auto* out = c->start_embed (arrayZ);
236 if (unlikely (!c->extend_size (out, get_size ()))) return_trace (hb_array_t ());
237 for (unsigned i = 0; i < length; i++)
238 out[i] = arrayZ[i]; /* TODO: add version that calls c->copy() */
239 return_trace (hb_array_t (out, length));
240 }
241
242 template <typename hb_sanitize_context_t>
sanitizehb_array_t243 bool sanitize (hb_sanitize_context_t *c) const
244 { return c->check_array (arrayZ, length); }
245
246 /*
247 * Members
248 */
249
250 public:
251 Type *arrayZ;
252 unsigned int length;
253 unsigned int backwards_length;
254 };
255 template <typename T> inline hb_array_t<T>
hb_array(T * array,unsigned int length)256 hb_array (T *array, unsigned int length)
257 { return hb_array_t<T> (array, length); }
258 template <typename T, unsigned int length_> inline hb_array_t<T>
hb_array(T (& array_)[length_])259 hb_array (T (&array_)[length_])
260 { return hb_array_t<T> (array_); }
261
262 enum hb_bfind_not_found_t
263 {
264 HB_BFIND_NOT_FOUND_DONT_STORE,
265 HB_BFIND_NOT_FOUND_STORE,
266 HB_BFIND_NOT_FOUND_STORE_CLOSEST,
267 };
268
269 template <typename Type>
270 struct hb_sorted_array_t :
271 hb_iter_t<hb_sorted_array_t<Type>, Type&>,
272 hb_array_t<Type>
273 {
274 typedef hb_iter_t<hb_sorted_array_t, Type&> iter_base_t;
275 HB_ITER_USING (iter_base_t);
276 static constexpr bool is_random_access_iterator = true;
277 static constexpr bool is_sorted_iterator = true;
278
hb_sorted_array_thb_sorted_array_t279 hb_sorted_array_t () : hb_array_t<Type> () {}
hb_sorted_array_thb_sorted_array_t280 hb_sorted_array_t (Type *array_, unsigned int length_) : hb_array_t<Type> (array_, length_) {}
281 template <unsigned int length_>
hb_sorted_array_thb_sorted_array_t282 hb_sorted_array_t (Type (&array_)[length_]) : hb_array_t<Type> (array_) {}
283
284 template <typename U,
285 hb_enable_if (hb_is_cr_convertible(U, Type))>
hb_sorted_array_thb_sorted_array_t286 hb_sorted_array_t (const hb_array_t<U> &o) :
287 hb_iter_t<hb_sorted_array_t, Type&> (),
288 hb_array_t<Type> (o) {}
289 template <typename U,
290 hb_enable_if (hb_is_cr_convertible(U, Type))>
operator =hb_sorted_array_t291 hb_sorted_array_t& operator = (const hb_array_t<U> &o)
292 { hb_array_t<Type> (*this) = o; return *this; }
293
294 /* Iterator implementation. */
operator !=hb_sorted_array_t295 bool operator != (const hb_sorted_array_t& o) const
296 { return this->arrayZ != o.arrayZ || this->length != o.length; }
297
sub_arrayhb_sorted_array_t298 hb_sorted_array_t sub_array (unsigned int start_offset, unsigned int *seg_count /* IN/OUT */) const
299 { return hb_sorted_array_t (((const hb_array_t<Type> *) (this))->sub_array (start_offset, seg_count)); }
sub_arrayhb_sorted_array_t300 hb_sorted_array_t sub_array (unsigned int start_offset, unsigned int seg_count) const
301 { return sub_array (start_offset, &seg_count); }
302
truncatehb_sorted_array_t303 hb_sorted_array_t truncate (unsigned length) const { return sub_array (0, length); }
304
305 template <typename T>
bsearchhb_sorted_array_t306 Type *bsearch (const T &x, Type *not_found = nullptr)
307 {
308 unsigned int i;
309 return bfind (x, &i) ? &this->arrayZ[i] : not_found;
310 }
311 template <typename T>
bsearchhb_sorted_array_t312 const Type *bsearch (const T &x, const Type *not_found = nullptr) const
313 {
314 unsigned int i;
315 return bfind (x, &i) ? &this->arrayZ[i] : not_found;
316 }
317 template <typename T>
bfindhb_sorted_array_t318 bool bfind (const T &x, unsigned int *i = nullptr,
319 hb_bfind_not_found_t not_found = HB_BFIND_NOT_FOUND_DONT_STORE,
320 unsigned int to_store = (unsigned int) -1) const
321 {
322 unsigned pos;
323
324 if (bsearch_impl (x, &pos))
325 {
326 if (i)
327 *i = pos;
328 return true;
329 }
330
331 if (i)
332 {
333 switch (not_found)
334 {
335 case HB_BFIND_NOT_FOUND_DONT_STORE:
336 break;
337
338 case HB_BFIND_NOT_FOUND_STORE:
339 *i = to_store;
340 break;
341
342 case HB_BFIND_NOT_FOUND_STORE_CLOSEST:
343 *i = pos;
344 break;
345 }
346 }
347 return false;
348 }
349 template <typename T>
bsearch_implhb_sorted_array_t350 bool bsearch_impl (const T &x, unsigned *pos) const
351 {
352 return hb_bsearch_impl (pos,
353 x,
354 this->arrayZ,
355 this->length,
356 sizeof (Type),
357 _hb_cmp_method<T, Type>);
358 }
359 };
360 template <typename T> inline hb_sorted_array_t<T>
hb_sorted_array(T * array,unsigned int length)361 hb_sorted_array (T *array, unsigned int length)
362 { return hb_sorted_array_t<T> (array, length); }
363 template <typename T, unsigned int length_> inline hb_sorted_array_t<T>
hb_sorted_array(T (& array_)[length_])364 hb_sorted_array (T (&array_)[length_])
365 { return hb_sorted_array_t<T> (array_); }
366
367 template <typename T>
operator ==(const hb_array_t<T> & o) const368 bool hb_array_t<T>::operator == (const hb_array_t<T> &o) const
369 {
370 if (o.length != this->length) return false;
371 for (unsigned int i = 0; i < this->length; i++) {
372 if (this->arrayZ[i] != o.arrayZ[i]) return false;
373 }
374 return true;
375 }
376
377 /* TODO Specialize opeator== for hb_bytes_t and hb_ubytes_t. */
378
379 template <>
hash() const380 inline uint32_t hb_array_t<const char>::hash () const {
381 uint32_t current = 0;
382 for (unsigned int i = 0; i < this->length; i++)
383 current = current * 31 + (uint32_t) (this->arrayZ[i] * 2654435761u);
384 return current;
385 }
386
387 template <>
hash() const388 inline uint32_t hb_array_t<const unsigned char>::hash () const {
389 uint32_t current = 0;
390 for (unsigned int i = 0; i < this->length; i++)
391 current = current * 31 + (uint32_t) (this->arrayZ[i] * 2654435761u);
392 return current;
393 }
394
395
396 typedef hb_array_t<const char> hb_bytes_t;
397 typedef hb_array_t<const unsigned char> hb_ubytes_t;
398
399
400
401 #endif /* HB_ARRAY_HH */
402