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1 | // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- |
2 | // vim: ts=8 sw=2 smarttab | |
3 | ||
4 | /* | |
5 | * Copyright (C) 2016 Red Hat Inc. | |
6 | */ | |
7 | ||
8 | ||
9 | #pragma once | |
10 | ||
11 | ||
12 | #include <memory> | |
13 | #include <vector> | |
14 | #include <string> | |
15 | #include <iostream> | |
16 | #include <functional> | |
17 | #include <algorithm> | |
18 | ||
19 | #include "assert.h" | |
20 | ||
21 | ||
22 | namespace crimson { | |
23 | using IndIntruHeapData = size_t; | |
24 | ||
25 | /* T is the ultimate data that's being stored in the heap, although | |
26 | * through indirection. | |
27 | * | |
28 | * I is the indirect type that will actually be stored in the heap | |
29 | * and that must allow dereferencing (via operator*) to yield a | |
30 | * T&. | |
31 | * | |
32 | * C is a functor when given two T&'s will return true if the first | |
33 | * must precede the second. | |
34 | * | |
35 | * heap_info is a data member pointer as to where the heap data in T | |
36 | * is stored. | |
37 | * | |
38 | * K is the branching factor of the heap, default is 2 (binary heap). | |
39 | */ | |
40 | template<typename I, | |
41 | typename T, | |
42 | IndIntruHeapData T::*heap_info, | |
43 | typename C, | |
44 | uint K = 2> | |
45 | class IndIntruHeap { | |
46 | ||
47 | // shorthand | |
48 | using HeapIndex = IndIntruHeapData; | |
49 | ||
50 | static_assert( | |
51 | std::is_same<T,typename std::pointer_traits<I>::element_type>::value, | |
52 | "class I must resolve to class T by indirection (pointer dereference)"); | |
53 | ||
54 | static_assert( | |
55 | std::is_same<bool, | |
56 | typename std::result_of<C(const T&,const T&)>::type>::value, | |
57 | "class C must define operator() to take two const T& and return a bool"); | |
58 | ||
59 | static_assert(K >= 2, "K (degree of branching) must be at least 2"); | |
60 | ||
61 | class Iterator { | |
62 | friend IndIntruHeap<I, T, heap_info, C, K>; | |
63 | ||
64 | IndIntruHeap<I, T, heap_info, C, K>& heap; | |
65 | HeapIndex index; | |
66 | ||
67 | Iterator(IndIntruHeap<I, T, heap_info, C, K>& _heap, HeapIndex _index) : | |
68 | heap(_heap), | |
69 | index(_index) | |
70 | { | |
71 | // empty | |
72 | } | |
73 | ||
74 | public: | |
75 | ||
76 | Iterator(Iterator&& other) : | |
77 | heap(other.heap), | |
78 | index(other.index) | |
79 | { | |
80 | // empty | |
81 | } | |
82 | ||
83 | Iterator(const Iterator& other) : | |
84 | heap(other.heap), | |
85 | index(other.index) | |
86 | { | |
87 | // empty | |
88 | } | |
89 | ||
90 | Iterator& operator=(Iterator&& other) { | |
91 | std::swap(heap, other.heap); | |
92 | std::swap(index, other.index); | |
93 | return *this; | |
94 | } | |
95 | ||
96 | Iterator& operator=(const Iterator& other) { | |
97 | heap = other.heap; | |
98 | index = other.index; | |
99 | } | |
100 | ||
101 | Iterator& operator++() { | |
102 | if (index <= heap.count) { | |
103 | ++index; | |
104 | } | |
105 | return *this; | |
106 | } | |
107 | ||
108 | bool operator==(const Iterator& other) const { | |
109 | return &heap == &other.heap && index == other.index; | |
110 | } | |
111 | ||
112 | bool operator!=(const Iterator& other) const { | |
113 | return !(*this == other); | |
114 | } | |
115 | ||
116 | T& operator*() { | |
117 | return *heap.data[index]; | |
118 | } | |
119 | ||
120 | T* operator->() { | |
121 | return &(*heap.data[index]); | |
122 | } | |
123 | ||
124 | #if 0 | |
125 | // the item this iterator refers to | |
126 | void increase() { | |
127 | heap.sift_up(index); | |
128 | } | |
129 | #endif | |
130 | }; // class Iterator | |
131 | ||
132 | ||
133 | class ConstIterator { | |
134 | friend IndIntruHeap<I, T, heap_info, C, K>; | |
135 | ||
136 | const IndIntruHeap<I, T, heap_info, C, K>& heap; | |
137 | HeapIndex index; | |
138 | ||
139 | ConstIterator(const IndIntruHeap<I, T, heap_info, C, K>& _heap, | |
140 | HeapIndex _index) : | |
141 | heap(_heap), | |
142 | index(_index) | |
143 | { | |
144 | // empty | |
145 | } | |
146 | ||
147 | public: | |
148 | ||
149 | ConstIterator(ConstIterator&& other) : | |
150 | heap(other.heap), | |
151 | index(other.index) | |
152 | { | |
153 | // empty | |
154 | } | |
155 | ||
156 | ConstIterator(const ConstIterator& other) : | |
157 | heap(other.heap), | |
158 | index(other.index) | |
159 | { | |
160 | // empty | |
161 | } | |
162 | ||
163 | ConstIterator& operator=(ConstIterator&& other) { | |
164 | std::swap(heap, other.heap); | |
165 | std::swap(index, other.index); | |
166 | return *this; | |
167 | } | |
168 | ||
169 | ConstIterator& operator=(const ConstIterator& other) { | |
170 | heap = other.heap; | |
171 | index = other.index; | |
172 | } | |
173 | ||
174 | ConstIterator& operator++() { | |
175 | if (index <= heap.count) { | |
176 | ++index; | |
177 | } | |
178 | return *this; | |
179 | } | |
180 | ||
181 | bool operator==(const ConstIterator& other) const { | |
182 | return &heap == &other.heap && index == other.index; | |
183 | } | |
184 | ||
185 | bool operator!=(const ConstIterator& other) const { | |
186 | return !(*this == other); | |
187 | } | |
188 | ||
189 | const T& operator*() { | |
190 | return *heap.data[index]; | |
191 | } | |
192 | ||
193 | const T* operator->() { | |
194 | return &(*heap.data[index]); | |
195 | } | |
196 | }; // class ConstIterator | |
197 | ||
198 | ||
199 | protected: | |
200 | ||
201 | std::vector<I> data; | |
202 | HeapIndex count; | |
203 | C comparator; | |
204 | ||
205 | public: | |
206 | ||
207 | IndIntruHeap() : | |
208 | count(0) | |
209 | { | |
210 | // empty | |
211 | } | |
212 | ||
213 | IndIntruHeap(const IndIntruHeap<I,T,heap_info,C,K>& other) : | |
214 | count(other.count) | |
215 | { | |
216 | for (HeapIndex i = 0; i < other.count; ++i) { | |
217 | data.push_back(other.data[i]); | |
218 | } | |
219 | } | |
220 | ||
221 | bool empty() const { return 0 == count; } | |
222 | ||
223 | size_t size() const { return (size_t) count; } | |
224 | ||
225 | T& top() { return *data[0]; } | |
226 | ||
227 | const T& top() const { return *data[0]; } | |
228 | ||
229 | I& top_ind() { return data[0]; } | |
230 | ||
231 | const I& top_ind() const { return data[0]; } | |
232 | ||
233 | void push(I&& item) { | |
234 | HeapIndex i = count++; | |
235 | intru_data_of(item) = i; | |
236 | data.emplace_back(std::move(item)); | |
237 | sift_up(i); | |
238 | } | |
239 | ||
240 | void push(const I& item) { | |
241 | I copy(item); | |
242 | push(std::move(copy)); | |
243 | } | |
244 | ||
245 | void pop() { | |
31f18b77 | 246 | remove(HeapIndex(0)); |
7c673cae FG |
247 | } |
248 | ||
249 | void remove(Iterator& i) { | |
250 | remove(i.index); | |
251 | i = end(); | |
252 | } | |
253 | ||
254 | Iterator find(const I& ind_item) { | |
255 | for (HeapIndex i = 0; i < count; ++i) { | |
256 | if (data[i] == ind_item) { | |
257 | return Iterator(*this, i); | |
258 | } | |
259 | } | |
260 | return end(); | |
261 | } | |
262 | ||
263 | // when passing in value we do a comparison via operator== | |
264 | Iterator find(const T& item) { | |
265 | for (HeapIndex i = 0; i < count; ++i) { | |
266 | if (*data[i] == item) { | |
267 | return Iterator(*this, i); | |
268 | } | |
269 | } | |
270 | return end(); | |
271 | } | |
272 | ||
273 | // reverse find -- start looking from bottom of heap | |
274 | Iterator rfind(const I& ind_item) { | |
275 | // HeapIndex is unsigned, so we can't allow to go negative; so | |
276 | // we'll keep it one more than actual index | |
277 | for (HeapIndex i = count; i > 0; --i) { | |
278 | if (data[i-1] == ind_item) { | |
279 | return Iterator(*this, i-1); | |
280 | } | |
281 | } | |
282 | return end(); | |
283 | } | |
284 | ||
285 | // reverse find -- start looking from bottom of heap | |
286 | Iterator rfind(const T& item) { | |
287 | // HeapIndex is unsigned, so we can't allow to go negative; so | |
288 | // we'll keep it one more than actual index | |
289 | for (HeapIndex i = count; i > 0; --i) { | |
290 | if (*data[i-1] == item) { | |
291 | return Iterator(*this, i-1); | |
292 | } | |
293 | } | |
294 | return end(); | |
295 | } | |
296 | ||
297 | ConstIterator find(const I& ind_item) const { | |
298 | for (HeapIndex i = 0; i < count; ++i) { | |
299 | if (data[i] == ind_item) { | |
300 | return ConstIterator(*this, i); | |
301 | } | |
302 | } | |
303 | return cend(); | |
304 | } | |
305 | ||
306 | // when passing in value we do a comparison via operator== | |
307 | ConstIterator find(const T& item) const { | |
308 | for (HeapIndex i = 0; i < count; ++i) { | |
309 | if (*data[i] == item) { | |
310 | return ConstIterator(*this, i); | |
311 | } | |
312 | } | |
313 | return cend(); | |
314 | } | |
315 | ||
316 | // reverse find -- start looking from bottom of heap | |
317 | ConstIterator rfind(const I& ind_item) const { | |
318 | // HeapIndex is unsigned, so we can't allow to go negative; so | |
319 | // we'll keep it one more than actual index | |
320 | for (HeapIndex i = count; i > 0; --i) { | |
321 | if (data[i-1] == ind_item) { | |
322 | return ConstIterator(*this, i-1); | |
323 | } | |
324 | } | |
325 | return cend(); | |
326 | } | |
327 | ||
328 | // reverse find -- start looking from bottom of heap | |
329 | ConstIterator rfind(const T& item) const { | |
330 | // HeapIndex is unsigned, so we can't allow to go negative; so | |
331 | // we'll keep it one more than actual index | |
332 | for (HeapIndex i = count; i > 0; --i) { | |
333 | if (*data[i-1] == item) { | |
334 | return ConstIterator(*this, i-1); | |
335 | } | |
336 | } | |
337 | return cend(); | |
338 | } | |
339 | ||
340 | void promote(T& item) { | |
341 | sift_up(item.*heap_info); | |
342 | } | |
343 | ||
344 | void demote(T& item) { | |
345 | sift_down(item.*heap_info); | |
346 | } | |
347 | ||
348 | void adjust(T& item) { | |
349 | sift(item.*heap_info); | |
350 | } | |
351 | ||
352 | Iterator begin() { | |
353 | return Iterator(*this, 0); | |
354 | } | |
355 | ||
356 | Iterator end() { | |
357 | return Iterator(*this, count); | |
358 | } | |
359 | ||
360 | ConstIterator cbegin() const { | |
361 | return ConstIterator(*this, 0); | |
362 | } | |
363 | ||
364 | ConstIterator cend() const { | |
365 | return ConstIterator(*this, count); | |
366 | } | |
367 | ||
368 | friend std::ostream& operator<<(std::ostream& out, const IndIntruHeap& h) { | |
369 | auto i = h.data.cbegin(); | |
370 | if (i != h.data.cend()) { | |
371 | out << **i; | |
372 | ++i; | |
373 | while (i != h.data.cend()) { | |
374 | out << ", " << **i; | |
375 | } | |
376 | } | |
377 | return out; | |
378 | } | |
379 | ||
380 | // can only be called if I is copyable; copies heap into a vector | |
381 | // and sorts it before displaying it | |
382 | std::ostream& | |
383 | display_sorted(std::ostream& out, | |
384 | std::function<bool(const T&)> filter = all_filter) const { | |
385 | static_assert(std::is_copy_constructible<I>::value, | |
386 | "cannot call display_sorted when class I is not copy" | |
387 | " constructible"); | |
388 | auto compare = [this] (const I first, const I second) -> bool { | |
389 | return this->comparator(*first, *second); | |
390 | }; | |
391 | std::vector<I> copy(data); | |
392 | std::sort(copy.begin(), copy.end(), compare); | |
393 | ||
394 | bool first = true; | |
395 | for (auto c = copy.begin(); c != copy.end(); ++c) { | |
396 | if (filter(**c)) { | |
397 | if (!first) { | |
398 | out << ", "; | |
399 | } else { | |
400 | first = false; | |
401 | } | |
402 | out << **c; | |
403 | } | |
404 | } | |
405 | ||
406 | return out; | |
407 | } | |
408 | ||
409 | ||
410 | protected: | |
411 | ||
412 | static IndIntruHeapData& intru_data_of(I& item) { | |
413 | return (*item).*heap_info; | |
414 | } | |
415 | ||
416 | void remove(HeapIndex i) { | |
417 | std::swap(data[i], data[--count]); | |
418 | intru_data_of(data[i]) = i; | |
419 | data.pop_back(); | |
420 | ||
421 | // the following needs to be sift (and not sift_down) as it can | |
422 | // go up or down the heap; imagine the heap vector contains 0, | |
423 | // 10, 100, 20, 30, 200, 300, 40; then 200 is removed, and 40 | |
424 | // would have to be sifted upwards | |
425 | // sift(i); | |
426 | sift(i); | |
427 | } | |
428 | ||
429 | // default value of filter parameter to display_sorted | |
430 | static bool all_filter(const T& data) { return true; } | |
431 | ||
432 | // when i is negative? | |
433 | static inline HeapIndex parent(HeapIndex i) { | |
434 | assert(0 != i); | |
435 | return (i - 1) / K; | |
436 | } | |
437 | ||
438 | // index of left child when K==2, index of left-most child when K>2 | |
439 | static inline HeapIndex lhs(HeapIndex i) { return K*i + 1; } | |
440 | ||
441 | // index of right child when K==2, index of right-most child when K>2 | |
442 | static inline HeapIndex rhs(HeapIndex i) { return K*i + K; } | |
443 | ||
444 | void sift_up(HeapIndex i) { | |
445 | while (i > 0) { | |
446 | HeapIndex pi = parent(i); | |
447 | if (!comparator(*data[i], *data[pi])) { | |
448 | break; | |
449 | } | |
450 | ||
451 | std::swap(data[i], data[pi]); | |
452 | intru_data_of(data[i]) = i; | |
453 | intru_data_of(data[pi]) = pi; | |
454 | i = pi; | |
455 | } | |
456 | } // sift_up | |
457 | ||
458 | // use this sift_down definition when K>2; it's more general and | |
459 | // uses a loop; EnableBool insures template uses a template | |
460 | // parameter | |
461 | template<bool EnableBool=true> | |
462 | typename std::enable_if<(K>2)&&EnableBool,void>::type sift_down(HeapIndex i) { | |
463 | if (i >= count) return; | |
464 | while (true) { | |
465 | HeapIndex li = lhs(i); | |
466 | ||
467 | if (li < count) { | |
468 | HeapIndex ri = std::min(rhs(i), count - 1); | |
469 | ||
470 | // find the index of min. child | |
471 | HeapIndex min_i = li; | |
472 | for (HeapIndex k = li + 1; k <= ri; ++k) { | |
473 | if (comparator(*data[k], *data[min_i])) { | |
474 | min_i = k; | |
475 | } | |
476 | } | |
477 | ||
478 | if (comparator(*data[min_i], *data[i])) { | |
479 | std::swap(data[i], data[min_i]); | |
480 | intru_data_of(data[i]) = i; | |
481 | intru_data_of(data[min_i]) = min_i; | |
482 | i = min_i; | |
483 | } else { | |
484 | // no child is smaller | |
485 | break; | |
486 | } | |
487 | } else { | |
488 | // no children | |
489 | break; | |
490 | } | |
491 | } | |
492 | } // sift_down | |
493 | ||
494 | // use this sift_down definition when K==2; EnableBool insures | |
495 | // template uses a template parameter | |
496 | template<bool EnableBool=true> | |
497 | typename std::enable_if<K==2&&EnableBool,void>::type sift_down(HeapIndex i) { | |
498 | if (i >= count) return; | |
499 | while (true) { | |
500 | const HeapIndex li = lhs(i); | |
501 | const HeapIndex ri = 1 + li; | |
502 | ||
503 | if (li < count) { | |
504 | if (comparator(*data[li], *data[i])) { | |
505 | if (ri < count && comparator(*data[ri], *data[li])) { | |
506 | std::swap(data[i], data[ri]); | |
507 | intru_data_of(data[i]) = i; | |
508 | intru_data_of(data[ri]) = ri; | |
509 | i = ri; | |
510 | } else { | |
511 | std::swap(data[i], data[li]); | |
512 | intru_data_of(data[i]) = i; | |
513 | intru_data_of(data[li]) = li; | |
514 | i = li; | |
515 | } | |
516 | } else if (ri < count && comparator(*data[ri], *data[i])) { | |
517 | std::swap(data[i], data[ri]); | |
518 | intru_data_of(data[i]) = i; | |
519 | intru_data_of(data[ri]) = ri; | |
520 | i = ri; | |
521 | } else { | |
522 | // no child is smaller | |
523 | break; | |
524 | } | |
525 | } else { | |
526 | // no children | |
527 | break; | |
528 | } | |
529 | } // while | |
530 | } // sift_down | |
531 | ||
532 | void sift(HeapIndex i) { | |
533 | if (i == 0) { | |
534 | // if we're at top, can only go down | |
535 | sift_down(i); | |
536 | } else { | |
537 | HeapIndex pi = parent(i); | |
538 | if (comparator(*data[i], *data[pi])) { | |
539 | // if we can go up, we will | |
540 | sift_up(i); | |
541 | } else { | |
542 | // otherwise we'll try to go down | |
543 | sift_down(i); | |
544 | } | |
545 | } | |
546 | } // sift | |
547 | }; // class IndIntruHeap | |
548 | ||
549 | } // namespace crimson |