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1 : //===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===//
2 : //
3 : // The LLVM Compiler Infrastructure
4 : //
5 : // This file is distributed under the University of Illinois Open Source
6 : // License. See LICENSE.TXT for details.
7 : //
8 : //===----------------------------------------------------------------------===//
9 : //
10 : // This file defines the SmallVector class.
11 : //
12 : //===----------------------------------------------------------------------===//
13 :
14 : #ifndef LLVM_ADT_SMALLVECTOR_H
15 : #define LLVM_ADT_SMALLVECTOR_H
16 :
17 : #include "llvm/ADT/iterator_range.h"
18 : #include "llvm/Support/AlignOf.h"
19 : #include "llvm/Support/Compiler.h"
20 : #include "llvm/Support/MathExtras.h"
21 : #include "llvm/Support/type_traits.h"
22 : #include <algorithm>
23 : #include <cassert>
24 : #include <cstddef>
25 : #include <cstdlib>
26 : #include <cstring>
27 : #include <initializer_list>
28 : #include <iterator>
29 : #include <memory>
30 :
31 : namespace llvm {
32 :
33 : /// This is all the non-templated stuff common to all SmallVectors.
34 : class SmallVectorBase {
35 : protected:
36 : void *BeginX, *EndX, *CapacityX;
37 :
38 : protected:
39 : SmallVectorBase(void *FirstEl, size_t Size)
40 2 : : BeginX(FirstEl), EndX(FirstEl), CapacityX((char*)FirstEl+Size) {}
41 :
42 : /// This is an implementation of the grow() method which only works
43 : /// on POD-like data types and is out of line to reduce code duplication.
44 : void grow_pod(void *FirstEl, size_t MinSizeInBytes, size_t TSize);
45 :
46 : public:
47 : /// This returns size()*sizeof(T).
48 : size_t size_in_bytes() const {
49 : return size_t((char*)EndX - (char*)BeginX);
50 : }
51 :
52 : /// capacity_in_bytes - This returns capacity()*sizeof(T).
53 : size_t capacity_in_bytes() const {
54 : return size_t((char*)CapacityX - (char*)BeginX);
55 : }
56 :
57 18 : bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const { return BeginX == EndX; }
58 : };
59 :
60 : template <typename T, unsigned N> struct SmallVectorStorage;
61 :
62 : /// This is the part of SmallVectorTemplateBase which does not depend on whether
63 : /// the type T is a POD. The extra dummy template argument is used by ArrayRef
64 : /// to avoid unnecessarily requiring T to be complete.
65 : template <typename T, typename = void>
66 : class SmallVectorTemplateCommon : public SmallVectorBase {
67 : private:
68 : template <typename, unsigned> friend struct SmallVectorStorage;
69 :
70 : // Allocate raw space for N elements of type T. If T has a ctor or dtor, we
71 : // don't want it to be automatically run, so we need to represent the space as
72 : // something else. Use an array of char of sufficient alignment.
73 : typedef llvm::AlignedCharArrayUnion<T> U;
74 : U FirstEl;
75 : // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
76 :
77 : protected:
78 2 : SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(&FirstEl, Size) {}
79 :
80 : void grow_pod(size_t MinSizeInBytes, size_t TSize) {
81 0 : SmallVectorBase::grow_pod(&FirstEl, MinSizeInBytes, TSize);
82 0 : }
83 :
84 : /// Return true if this is a smallvector which has not had dynamic
85 : /// memory allocated for it.
86 : bool isSmall() const {
87 2 : return BeginX == static_cast<const void*>(&FirstEl);
88 : }
89 :
90 : /// Put this vector in a state of being small.
91 : void resetToSmall() {
92 : BeginX = EndX = CapacityX = &FirstEl;
93 : }
94 :
95 10 : void setEnd(T *P) { this->EndX = P; }
96 : public:
97 : typedef size_t size_type;
98 : typedef ptrdiff_t difference_type;
99 : typedef T value_type;
100 : typedef T *iterator;
101 : typedef const T *const_iterator;
102 :
103 : typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
104 : typedef std::reverse_iterator<iterator> reverse_iterator;
105 :
106 : typedef T &reference;
107 : typedef const T &const_reference;
108 : typedef T *pointer;
109 : typedef const T *const_pointer;
110 :
111 : // forward iterator creation methods.
112 2 : iterator begin() { return (iterator)this->BeginX; }
113 33 : const_iterator begin() const { return (const_iterator)this->BeginX; }
114 25 : iterator end() { return (iterator)this->EndX; }
115 22 : const_iterator end() const { return (const_iterator)this->EndX; }
116 : protected:
117 : iterator capacity_ptr() { return (iterator)this->CapacityX; }
118 : const_iterator capacity_ptr() const { return (const_iterator)this->CapacityX;}
119 : public:
120 :
121 : // reverse iterator creation methods.
122 : reverse_iterator rbegin() { return reverse_iterator(end()); }
123 : const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
124 : reverse_iterator rend() { return reverse_iterator(begin()); }
125 : const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
126 :
127 22 : size_type size() const { return end()-begin(); }
128 : size_type max_size() const { return size_type(-1) / sizeof(T); }
129 :
130 : /// Return the total number of elements in the currently allocated buffer.
131 : size_t capacity() const { return capacity_ptr() - begin(); }
132 :
133 : /// Return a pointer to the vector's buffer, even if empty().
134 : pointer data() { return pointer(begin()); }
135 : /// Return a pointer to the vector's buffer, even if empty().
136 0 : const_pointer data() const { return const_pointer(begin()); }
137 :
138 : reference operator[](size_type idx) {
139 0 : assert(idx < size());
140 0 : return begin()[idx];
141 : }
142 : const_reference operator[](size_type idx) const {
143 22 : assert(idx < size());
144 11 : return begin()[idx];
145 : }
146 :
147 : reference front() {
148 : assert(!empty());
149 : return begin()[0];
150 : }
151 : const_reference front() const {
152 : assert(!empty());
153 : return begin()[0];
154 : }
155 :
156 : reference back() {
157 16 : assert(!empty());
158 8 : return end()[-1];
159 : }
160 : const_reference back() const {
161 : assert(!empty());
162 : return end()[-1];
163 : }
164 : };
165 :
166 : /// SmallVectorTemplateBase<isPodLike = false> - This is where we put method
167 : /// implementations that are designed to work with non-POD-like T's.
168 : template <typename T, bool isPodLike>
169 : class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
170 : protected:
171 : SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
172 :
173 : static void destroy_range(T *S, T *E) {
174 : while (S != E) {
175 : --E;
176 : E->~T();
177 : }
178 : }
179 :
180 : /// Use move-assignment to move the range [I, E) onto the
181 : /// objects starting with "Dest". This is just <memory>'s
182 : /// std::move, but not all stdlibs actually provide that.
183 : template<typename It1, typename It2>
184 : static It2 move(It1 I, It1 E, It2 Dest) {
185 : for (; I != E; ++I, ++Dest)
186 : *Dest = ::std::move(*I);
187 : return Dest;
188 : }
189 :
190 : /// Use move-assignment to move the range
191 : /// [I, E) onto the objects ending at "Dest", moving objects
192 : /// in reverse order. This is just <algorithm>'s
193 : /// std::move_backward, but not all stdlibs actually provide that.
194 : template<typename It1, typename It2>
195 : static It2 move_backward(It1 I, It1 E, It2 Dest) {
196 : while (I != E)
197 : *--Dest = ::std::move(*--E);
198 : return Dest;
199 : }
200 :
201 : /// Move the range [I, E) into the uninitialized memory starting with "Dest",
202 : /// constructing elements as needed.
203 : template<typename It1, typename It2>
204 : static void uninitialized_move(It1 I, It1 E, It2 Dest) {
205 : for (; I != E; ++I, ++Dest)
206 : ::new ((void*) &*Dest) T(::std::move(*I));
207 : }
208 :
209 : /// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
210 : /// constructing elements as needed.
211 : template<typename It1, typename It2>
212 : static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
213 : std::uninitialized_copy(I, E, Dest);
214 : }
215 :
216 : /// Grow the allocated memory (without initializing new elements), doubling
217 : /// the size of the allocated memory. Guarantees space for at least one more
218 : /// element, or MinSize more elements if specified.
219 : void grow(size_t MinSize = 0);
220 :
221 : public:
222 : void push_back(const T &Elt) {
223 : if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
224 : this->grow();
225 : ::new ((void*) this->end()) T(Elt);
226 : this->setEnd(this->end()+1);
227 : }
228 :
229 : void push_back(T &&Elt) {
230 : if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
231 : this->grow();
232 : ::new ((void*) this->end()) T(::std::move(Elt));
233 : this->setEnd(this->end()+1);
234 : }
235 :
236 : void pop_back() {
237 : this->setEnd(this->end()-1);
238 : this->end()->~T();
239 : }
240 : };
241 :
242 : // Define this out-of-line to dissuade the C++ compiler from inlining it.
243 : template <typename T, bool isPodLike>
244 : void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
245 : size_t CurCapacity = this->capacity();
246 : size_t CurSize = this->size();
247 : // Always grow, even from zero.
248 : size_t NewCapacity = size_t(NextPowerOf2(CurCapacity+2));
249 : if (NewCapacity < MinSize)
250 : NewCapacity = MinSize;
251 : T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
252 :
253 : // Move the elements over.
254 : this->uninitialized_move(this->begin(), this->end(), NewElts);
255 :
256 : // Destroy the original elements.
257 : destroy_range(this->begin(), this->end());
258 :
259 : // If this wasn't grown from the inline copy, deallocate the old space.
260 : if (!this->isSmall())
261 : free(this->begin());
262 :
263 : this->setEnd(NewElts+CurSize);
264 : this->BeginX = NewElts;
265 : this->CapacityX = this->begin()+NewCapacity;
266 : }
267 :
268 :
269 : /// SmallVectorTemplateBase<isPodLike = true> - This is where we put method
270 : /// implementations that are designed to work with POD-like T's.
271 : template <typename T>
272 : class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
273 : protected:
274 2 : SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
275 :
276 : // No need to do a destroy loop for POD's.
277 2 : static void destroy_range(T *, T *) {}
278 :
279 : /// Use move-assignment to move the range [I, E) onto the
280 : /// objects starting with "Dest". For PODs, this is just memcpy.
281 : template<typename It1, typename It2>
282 : static It2 move(It1 I, It1 E, It2 Dest) {
283 : return ::std::copy(I, E, Dest);
284 : }
285 :
286 : /// Use move-assignment to move the range [I, E) onto the objects ending at
287 : /// "Dest", moving objects in reverse order.
288 : template<typename It1, typename It2>
289 : static It2 move_backward(It1 I, It1 E, It2 Dest) {
290 : return ::std::copy_backward(I, E, Dest);
291 : }
292 :
293 : /// Move the range [I, E) onto the uninitialized memory
294 : /// starting with "Dest", constructing elements into it as needed.
295 : template<typename It1, typename It2>
296 : static void uninitialized_move(It1 I, It1 E, It2 Dest) {
297 : // Just do a copy.
298 : uninitialized_copy(I, E, Dest);
299 : }
300 :
301 : /// Copy the range [I, E) onto the uninitialized memory
302 : /// starting with "Dest", constructing elements into it as needed.
303 : template<typename It1, typename It2>
304 : static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
305 : // Arbitrary iterator types; just use the basic implementation.
306 : std::uninitialized_copy(I, E, Dest);
307 : }
308 :
309 : /// Copy the range [I, E) onto the uninitialized memory
310 : /// starting with "Dest", constructing elements into it as needed.
311 : template <typename T1, typename T2>
312 : static void uninitialized_copy(
313 : T1 *I, T1 *E, T2 *Dest,
314 : typename std::enable_if<std::is_same<typename std::remove_const<T1>::type,
315 : T2>::value>::type * = nullptr) {
316 : // Use memcpy for PODs iterated by pointers (which includes SmallVector
317 : // iterators): std::uninitialized_copy optimizes to memmove, but we can
318 : // use memcpy here. Note that I and E are iterators and thus might be
319 : // invalid for memcpy if they are equal.
320 : if (I != E)
321 : memcpy(Dest, I, (E - I) * sizeof(T));
322 : }
323 :
324 : /// Double the size of the allocated memory, guaranteeing space for at
325 : /// least one more element or MinSize if specified.
326 : void grow(size_t MinSize = 0) {
327 0 : this->grow_pod(MinSize*sizeof(T), sizeof(T));
328 0 : }
329 : public:
330 : void push_back(const T &Elt) {
331 5 : if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
332 0 : this->grow();
333 5 : memcpy(this->end(), &Elt, sizeof(T));
334 5 : this->setEnd(this->end()+1);
335 5 : }
336 :
337 : void pop_back() {
338 5 : this->setEnd(this->end()-1);
339 5 : }
340 : };
341 :
342 :
343 : /// This class consists of common code factored out of the SmallVector class to
344 : /// reduce code duplication based on the SmallVector 'N' template parameter.
345 : template <typename T>
346 : class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> {
347 : typedef SmallVectorTemplateBase<T, isPodLike<T>::value > SuperClass;
348 :
349 : SmallVectorImpl(const SmallVectorImpl&) = delete;
350 : public:
351 : typedef typename SuperClass::iterator iterator;
352 : typedef typename SuperClass::size_type size_type;
353 :
354 : protected:
355 : // Default ctor - Initialize to empty.
356 : explicit SmallVectorImpl(unsigned N)
357 2 : : SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) {
358 2 : }
359 :
360 : public:
361 : ~SmallVectorImpl() {
362 : // Destroy the constructed elements in the vector.
363 6 : this->destroy_range(this->begin(), this->end());
364 :
365 : // If this wasn't grown from the inline copy, deallocate the old space.
366 4 : if (!this->isSmall())
367 0 : free(this->begin());
368 2 : }
369 :
370 :
371 : void clear() {
372 : this->destroy_range(this->begin(), this->end());
373 : this->EndX = this->BeginX;
374 : }
375 :
376 : void resize(size_type N) {
377 : if (N < this->size()) {
378 : this->destroy_range(this->begin()+N, this->end());
379 : this->setEnd(this->begin()+N);
380 : } else if (N > this->size()) {
381 : if (this->capacity() < N)
382 : this->grow(N);
383 : for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
384 : new (&*I) T();
385 : this->setEnd(this->begin()+N);
386 : }
387 : }
388 :
389 : void resize(size_type N, const T &NV) {
390 : if (N < this->size()) {
391 : this->destroy_range(this->begin()+N, this->end());
392 : this->setEnd(this->begin()+N);
393 : } else if (N > this->size()) {
394 : if (this->capacity() < N)
395 : this->grow(N);
396 : std::uninitialized_fill(this->end(), this->begin()+N, NV);
397 : this->setEnd(this->begin()+N);
398 : }
399 : }
400 :
401 : void reserve(size_type N) {
402 : if (this->capacity() < N)
403 : this->grow(N);
404 : }
405 :
406 : T LLVM_ATTRIBUTE_UNUSED_RESULT pop_back_val() {
407 : T Result = ::std::move(this->back());
408 : this->pop_back();
409 : return Result;
410 : }
411 :
412 : void swap(SmallVectorImpl &RHS);
413 :
414 : /// Add the specified range to the end of the SmallVector.
415 : template<typename in_iter>
416 : void append(in_iter in_start, in_iter in_end) {
417 : size_type NumInputs = std::distance(in_start, in_end);
418 : // Grow allocated space if needed.
419 : if (NumInputs > size_type(this->capacity_ptr()-this->end()))
420 : this->grow(this->size()+NumInputs);
421 :
422 : // Copy the new elements over.
423 : this->uninitialized_copy(in_start, in_end, this->end());
424 : this->setEnd(this->end() + NumInputs);
425 : }
426 :
427 : /// Add the specified range to the end of the SmallVector.
428 : void append(size_type NumInputs, const T &Elt) {
429 : // Grow allocated space if needed.
430 : if (NumInputs > size_type(this->capacity_ptr()-this->end()))
431 : this->grow(this->size()+NumInputs);
432 :
433 : // Copy the new elements over.
434 : std::uninitialized_fill_n(this->end(), NumInputs, Elt);
435 : this->setEnd(this->end() + NumInputs);
436 : }
437 :
438 : void append(std::initializer_list<T> IL) {
439 : append(IL.begin(), IL.end());
440 : }
441 :
442 : void assign(size_type NumElts, const T &Elt) {
443 : clear();
444 : if (this->capacity() < NumElts)
445 : this->grow(NumElts);
446 : this->setEnd(this->begin()+NumElts);
447 : std::uninitialized_fill(this->begin(), this->end(), Elt);
448 : }
449 :
450 : void assign(std::initializer_list<T> IL) {
451 : clear();
452 : append(IL);
453 : }
454 :
455 : iterator erase(iterator I) {
456 : assert(I >= this->begin() && "Iterator to erase is out of bounds.");
457 : assert(I < this->end() && "Erasing at past-the-end iterator.");
458 :
459 : iterator N = I;
460 : // Shift all elts down one.
461 : this->move(I+1, this->end(), I);
462 : // Drop the last elt.
463 : this->pop_back();
464 : return(N);
465 : }
466 :
467 : iterator erase(iterator S, iterator E) {
468 : assert(S >= this->begin() && "Range to erase is out of bounds.");
469 : assert(S <= E && "Trying to erase invalid range.");
470 : assert(E <= this->end() && "Trying to erase past the end.");
471 :
472 : iterator N = S;
473 : // Shift all elts down.
474 : iterator I = this->move(E, this->end(), S);
475 : // Drop the last elts.
476 : this->destroy_range(I, this->end());
477 : this->setEnd(I);
478 : return(N);
479 : }
480 :
481 : iterator insert(iterator I, T &&Elt) {
482 : if (I == this->end()) { // Important special case for empty vector.
483 : this->push_back(::std::move(Elt));
484 : return this->end()-1;
485 : }
486 :
487 : assert(I >= this->begin() && "Insertion iterator is out of bounds.");
488 : assert(I <= this->end() && "Inserting past the end of the vector.");
489 :
490 : if (this->EndX >= this->CapacityX) {
491 : size_t EltNo = I-this->begin();
492 : this->grow();
493 : I = this->begin()+EltNo;
494 : }
495 :
496 : ::new ((void*) this->end()) T(::std::move(this->back()));
497 : // Push everything else over.
498 : this->move_backward(I, this->end()-1, this->end());
499 : this->setEnd(this->end()+1);
500 :
501 : // If we just moved the element we're inserting, be sure to update
502 : // the reference.
503 : T *EltPtr = &Elt;
504 : if (I <= EltPtr && EltPtr < this->EndX)
505 : ++EltPtr;
506 :
507 : *I = ::std::move(*EltPtr);
508 : return I;
509 : }
510 :
511 : iterator insert(iterator I, const T &Elt) {
512 : if (I == this->end()) { // Important special case for empty vector.
513 : this->push_back(Elt);
514 : return this->end()-1;
515 : }
516 :
517 : assert(I >= this->begin() && "Insertion iterator is out of bounds.");
518 : assert(I <= this->end() && "Inserting past the end of the vector.");
519 :
520 : if (this->EndX >= this->CapacityX) {
521 : size_t EltNo = I-this->begin();
522 : this->grow();
523 : I = this->begin()+EltNo;
524 : }
525 : ::new ((void*) this->end()) T(std::move(this->back()));
526 : // Push everything else over.
527 : this->move_backward(I, this->end()-1, this->end());
528 : this->setEnd(this->end()+1);
529 :
530 : // If we just moved the element we're inserting, be sure to update
531 : // the reference.
532 : const T *EltPtr = &Elt;
533 : if (I <= EltPtr && EltPtr < this->EndX)
534 : ++EltPtr;
535 :
536 : *I = *EltPtr;
537 : return I;
538 : }
539 :
540 : iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
541 : // Convert iterator to elt# to avoid invalidating iterator when we reserve()
542 : size_t InsertElt = I - this->begin();
543 :
544 : if (I == this->end()) { // Important special case for empty vector.
545 : append(NumToInsert, Elt);
546 : return this->begin()+InsertElt;
547 : }
548 :
549 : assert(I >= this->begin() && "Insertion iterator is out of bounds.");
550 : assert(I <= this->end() && "Inserting past the end of the vector.");
551 :
552 : // Ensure there is enough space.
553 : reserve(this->size() + NumToInsert);
554 :
555 : // Uninvalidate the iterator.
556 : I = this->begin()+InsertElt;
557 :
558 : // If there are more elements between the insertion point and the end of the
559 : // range than there are being inserted, we can use a simple approach to
560 : // insertion. Since we already reserved space, we know that this won't
561 : // reallocate the vector.
562 : if (size_t(this->end()-I) >= NumToInsert) {
563 : T *OldEnd = this->end();
564 : append(std::move_iterator<iterator>(this->end() - NumToInsert),
565 : std::move_iterator<iterator>(this->end()));
566 :
567 : // Copy the existing elements that get replaced.
568 : this->move_backward(I, OldEnd-NumToInsert, OldEnd);
569 :
570 : std::fill_n(I, NumToInsert, Elt);
571 : return I;
572 : }
573 :
574 : // Otherwise, we're inserting more elements than exist already, and we're
575 : // not inserting at the end.
576 :
577 : // Move over the elements that we're about to overwrite.
578 : T *OldEnd = this->end();
579 : this->setEnd(this->end() + NumToInsert);
580 : size_t NumOverwritten = OldEnd-I;
581 : this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
582 :
583 : // Replace the overwritten part.
584 : std::fill_n(I, NumOverwritten, Elt);
585 :
586 : // Insert the non-overwritten middle part.
587 : std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
588 : return I;
589 : }
590 :
591 : template<typename ItTy>
592 : iterator insert(iterator I, ItTy From, ItTy To) {
593 : // Convert iterator to elt# to avoid invalidating iterator when we reserve()
594 : size_t InsertElt = I - this->begin();
595 :
596 : if (I == this->end()) { // Important special case for empty vector.
597 : append(From, To);
598 : return this->begin()+InsertElt;
599 : }
600 :
601 : assert(I >= this->begin() && "Insertion iterator is out of bounds.");
602 : assert(I <= this->end() && "Inserting past the end of the vector.");
603 :
604 : size_t NumToInsert = std::distance(From, To);
605 :
606 : // Ensure there is enough space.
607 : reserve(this->size() + NumToInsert);
608 :
609 : // Uninvalidate the iterator.
610 : I = this->begin()+InsertElt;
611 :
612 : // If there are more elements between the insertion point and the end of the
613 : // range than there are being inserted, we can use a simple approach to
614 : // insertion. Since we already reserved space, we know that this won't
615 : // reallocate the vector.
616 : if (size_t(this->end()-I) >= NumToInsert) {
617 : T *OldEnd = this->end();
618 : append(std::move_iterator<iterator>(this->end() - NumToInsert),
619 : std::move_iterator<iterator>(this->end()));
620 :
621 : // Copy the existing elements that get replaced.
622 : this->move_backward(I, OldEnd-NumToInsert, OldEnd);
623 :
624 : std::copy(From, To, I);
625 : return I;
626 : }
627 :
628 : // Otherwise, we're inserting more elements than exist already, and we're
629 : // not inserting at the end.
630 :
631 : // Move over the elements that we're about to overwrite.
632 : T *OldEnd = this->end();
633 : this->setEnd(this->end() + NumToInsert);
634 : size_t NumOverwritten = OldEnd-I;
635 : this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
636 :
637 : // Replace the overwritten part.
638 : for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
639 : *J = *From;
640 : ++J; ++From;
641 : }
642 :
643 : // Insert the non-overwritten middle part.
644 : this->uninitialized_copy(From, To, OldEnd);
645 : return I;
646 : }
647 :
648 : void insert(iterator I, std::initializer_list<T> IL) {
649 : insert(I, IL.begin(), IL.end());
650 : }
651 :
652 : template <typename... ArgTypes> void emplace_back(ArgTypes &&... Args) {
653 : if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
654 : this->grow();
655 : ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
656 : this->setEnd(this->end() + 1);
657 : }
658 :
659 : SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
660 :
661 : SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
662 :
663 : bool operator==(const SmallVectorImpl &RHS) const {
664 : if (this->size() != RHS.size()) return false;
665 : return std::equal(this->begin(), this->end(), RHS.begin());
666 : }
667 : bool operator!=(const SmallVectorImpl &RHS) const {
668 : return !(*this == RHS);
669 : }
670 :
671 : bool operator<(const SmallVectorImpl &RHS) const {
672 : return std::lexicographical_compare(this->begin(), this->end(),
673 : RHS.begin(), RHS.end());
674 : }
675 :
676 : /// Set the array size to \p N, which the current array must have enough
677 : /// capacity for.
678 : ///
679 : /// This does not construct or destroy any elements in the vector.
680 : ///
681 : /// Clients can use this in conjunction with capacity() to write past the end
682 : /// of the buffer when they know that more elements are available, and only
683 : /// update the size later. This avoids the cost of value initializing elements
684 : /// which will only be overwritten.
685 : void set_size(size_type N) {
686 : assert(N <= this->capacity());
687 : this->setEnd(this->begin() + N);
688 : }
689 : };
690 :
691 :
692 : template <typename T>
693 : void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
694 : if (this == &RHS) return;
695 :
696 : // We can only avoid copying elements if neither vector is small.
697 : if (!this->isSmall() && !RHS.isSmall()) {
698 : std::swap(this->BeginX, RHS.BeginX);
699 : std::swap(this->EndX, RHS.EndX);
700 : std::swap(this->CapacityX, RHS.CapacityX);
701 : return;
702 : }
703 : if (RHS.size() > this->capacity())
704 : this->grow(RHS.size());
705 : if (this->size() > RHS.capacity())
706 : RHS.grow(this->size());
707 :
708 : // Swap the shared elements.
709 : size_t NumShared = this->size();
710 : if (NumShared > RHS.size()) NumShared = RHS.size();
711 : for (size_type i = 0; i != NumShared; ++i)
712 : std::swap((*this)[i], RHS[i]);
713 :
714 : // Copy over the extra elts.
715 : if (this->size() > RHS.size()) {
716 : size_t EltDiff = this->size() - RHS.size();
717 : this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
718 : RHS.setEnd(RHS.end()+EltDiff);
719 : this->destroy_range(this->begin()+NumShared, this->end());
720 : this->setEnd(this->begin()+NumShared);
721 : } else if (RHS.size() > this->size()) {
722 : size_t EltDiff = RHS.size() - this->size();
723 : this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
724 : this->setEnd(this->end() + EltDiff);
725 : this->destroy_range(RHS.begin()+NumShared, RHS.end());
726 : RHS.setEnd(RHS.begin()+NumShared);
727 : }
728 : }
729 :
730 : template <typename T>
731 : SmallVectorImpl<T> &SmallVectorImpl<T>::
732 : operator=(const SmallVectorImpl<T> &RHS) {
733 : // Avoid self-assignment.
734 : if (this == &RHS) return *this;
735 :
736 : // If we already have sufficient space, assign the common elements, then
737 : // destroy any excess.
738 : size_t RHSSize = RHS.size();
739 : size_t CurSize = this->size();
740 : if (CurSize >= RHSSize) {
741 : // Assign common elements.
742 : iterator NewEnd;
743 : if (RHSSize)
744 : NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
745 : else
746 : NewEnd = this->begin();
747 :
748 : // Destroy excess elements.
749 : this->destroy_range(NewEnd, this->end());
750 :
751 : // Trim.
752 : this->setEnd(NewEnd);
753 : return *this;
754 : }
755 :
756 : // If we have to grow to have enough elements, destroy the current elements.
757 : // This allows us to avoid copying them during the grow.
758 : // FIXME: don't do this if they're efficiently moveable.
759 : if (this->capacity() < RHSSize) {
760 : // Destroy current elements.
761 : this->destroy_range(this->begin(), this->end());
762 : this->setEnd(this->begin());
763 : CurSize = 0;
764 : this->grow(RHSSize);
765 : } else if (CurSize) {
766 : // Otherwise, use assignment for the already-constructed elements.
767 : std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
768 : }
769 :
770 : // Copy construct the new elements in place.
771 : this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
772 : this->begin()+CurSize);
773 :
774 : // Set end.
775 : this->setEnd(this->begin()+RHSSize);
776 : return *this;
777 : }
778 :
779 : template <typename T>
780 : SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
781 : // Avoid self-assignment.
782 : if (this == &RHS) return *this;
783 :
784 : // If the RHS isn't small, clear this vector and then steal its buffer.
785 : if (!RHS.isSmall()) {
786 : this->destroy_range(this->begin(), this->end());
787 : if (!this->isSmall()) free(this->begin());
788 : this->BeginX = RHS.BeginX;
789 : this->EndX = RHS.EndX;
790 : this->CapacityX = RHS.CapacityX;
791 : RHS.resetToSmall();
792 : return *this;
793 : }
794 :
795 : // If we already have sufficient space, assign the common elements, then
796 : // destroy any excess.
797 : size_t RHSSize = RHS.size();
798 : size_t CurSize = this->size();
799 : if (CurSize >= RHSSize) {
800 : // Assign common elements.
801 : iterator NewEnd = this->begin();
802 : if (RHSSize)
803 : NewEnd = this->move(RHS.begin(), RHS.end(), NewEnd);
804 :
805 : // Destroy excess elements and trim the bounds.
806 : this->destroy_range(NewEnd, this->end());
807 : this->setEnd(NewEnd);
808 :
809 : // Clear the RHS.
810 : RHS.clear();
811 :
812 : return *this;
813 : }
814 :
815 : // If we have to grow to have enough elements, destroy the current elements.
816 : // This allows us to avoid copying them during the grow.
817 : // FIXME: this may not actually make any sense if we can efficiently move
818 : // elements.
819 : if (this->capacity() < RHSSize) {
820 : // Destroy current elements.
821 : this->destroy_range(this->begin(), this->end());
822 : this->setEnd(this->begin());
823 : CurSize = 0;
824 : this->grow(RHSSize);
825 : } else if (CurSize) {
826 : // Otherwise, use assignment for the already-constructed elements.
827 : this->move(RHS.begin(), RHS.begin()+CurSize, this->begin());
828 : }
829 :
830 : // Move-construct the new elements in place.
831 : this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
832 : this->begin()+CurSize);
833 :
834 : // Set end.
835 : this->setEnd(this->begin()+RHSSize);
836 :
837 : RHS.clear();
838 : return *this;
839 : }
840 :
841 : /// Storage for the SmallVector elements which aren't contained in
842 : /// SmallVectorTemplateCommon. There are 'N-1' elements here. The remaining '1'
843 : /// element is in the base class. This is specialized for the N=1 and N=0 cases
844 : /// to avoid allocating unnecessary storage.
845 : template <typename T, unsigned N>
846 : struct SmallVectorStorage {
847 : typename SmallVectorTemplateCommon<T>::U InlineElts[N - 1];
848 : };
849 : template <typename T> struct SmallVectorStorage<T, 1> {};
850 : template <typename T> struct SmallVectorStorage<T, 0> {};
851 :
852 : /// This is a 'vector' (really, a variable-sized array), optimized
853 : /// for the case when the array is small. It contains some number of elements
854 : /// in-place, which allows it to avoid heap allocation when the actual number of
855 : /// elements is below that threshold. This allows normal "small" cases to be
856 : /// fast without losing generality for large inputs.
857 : ///
858 : /// Note that this does not attempt to be exception safe.
859 : ///
860 : template <typename T, unsigned N>
861 : class SmallVector : public SmallVectorImpl<T> {
862 : /// Inline space for elements which aren't stored in the base class.
863 : SmallVectorStorage<T, N> Storage;
864 : public:
865 2 : SmallVector() : SmallVectorImpl<T>(N) {
866 2 : }
867 :
868 : explicit SmallVector(size_t Size, const T &Value = T())
869 : : SmallVectorImpl<T>(N) {
870 : this->assign(Size, Value);
871 : }
872 :
873 : template<typename ItTy>
874 : SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
875 : this->append(S, E);
876 : }
877 :
878 : template <typename RangeTy>
879 : explicit SmallVector(const llvm::iterator_range<RangeTy> R)
880 : : SmallVectorImpl<T>(N) {
881 : this->append(R.begin(), R.end());
882 : }
883 :
884 : SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
885 : this->assign(IL);
886 : }
887 :
888 : SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
889 : if (!RHS.empty())
890 : SmallVectorImpl<T>::operator=(RHS);
891 : }
892 :
893 : const SmallVector &operator=(const SmallVector &RHS) {
894 : SmallVectorImpl<T>::operator=(RHS);
895 : return *this;
896 : }
897 :
898 : SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
899 : if (!RHS.empty())
900 : SmallVectorImpl<T>::operator=(::std::move(RHS));
901 : }
902 :
903 : const SmallVector &operator=(SmallVector &&RHS) {
904 : SmallVectorImpl<T>::operator=(::std::move(RHS));
905 : return *this;
906 : }
907 :
908 : SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
909 : if (!RHS.empty())
910 : SmallVectorImpl<T>::operator=(::std::move(RHS));
911 : }
912 :
913 : const SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
914 : SmallVectorImpl<T>::operator=(::std::move(RHS));
915 : return *this;
916 : }
917 :
918 : const SmallVector &operator=(std::initializer_list<T> IL) {
919 : this->assign(IL);
920 : return *this;
921 : }
922 : };
923 :
924 : template<typename T, unsigned N>
925 : static inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
926 : return X.capacity_in_bytes();
927 : }
928 :
929 : } // End llvm namespace
930 :
931 : namespace std {
932 : /// Implement std::swap in terms of SmallVector swap.
933 : template<typename T>
934 : inline void
935 : swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
936 : LHS.swap(RHS);
937 : }
938 :
939 : /// Implement std::swap in terms of SmallVector swap.
940 : template<typename T, unsigned N>
941 : inline void
942 : swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {
943 : LHS.swap(RHS);
944 : }
945 : }
946 :
947 : #endif
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