1 //===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the SmallVector class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ADT_SMALLVECTOR_H
15 #define LLVM_ADT_SMALLVECTOR_H
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"
32 /// This is all the non-templated stuff common to all SmallVectors.
33 class SmallVectorBase {
35 void *BeginX, *EndX, *CapacityX;
38 SmallVectorBase(void *FirstEl, size_t Size)
39 : BeginX(FirstEl), EndX(FirstEl), CapacityX((char*)FirstEl+Size) {}
41 /// This is an implementation of the grow() method which only works
42 /// on POD-like data types and is out of line to reduce code duplication.
43 void grow_pod(void *FirstEl, size_t MinSizeInBytes, size_t TSize);
46 /// This returns size()*sizeof(T).
47 size_t size_in_bytes() const {
48 return size_t((char*)EndX - (char*)BeginX);
51 /// capacity_in_bytes - This returns capacity()*sizeof(T).
52 size_t capacity_in_bytes() const {
53 return size_t((char*)CapacityX - (char*)BeginX);
56 bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const { return BeginX == EndX; }
59 template <typename T, unsigned N> struct SmallVectorStorage;
61 /// This is the part of SmallVectorTemplateBase which does not depend on whether
62 /// the type T is a POD. The extra dummy template argument is used by ArrayRef
63 /// to avoid unnecessarily requiring T to be complete.
64 template <typename T, typename = void>
65 class SmallVectorTemplateCommon : public SmallVectorBase {
67 template <typename, unsigned> friend struct SmallVectorStorage;
69 // Allocate raw space for N elements of type T. If T has a ctor or dtor, we
70 // don't want it to be automatically run, so we need to represent the space as
71 // something else. Use an array of char of sufficient alignment.
72 typedef llvm::AlignedCharArrayUnion<T> U;
74 // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
77 SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(&FirstEl, Size) {}
79 void grow_pod(size_t MinSizeInBytes, size_t TSize) {
80 SmallVectorBase::grow_pod(&FirstEl, MinSizeInBytes, TSize);
83 /// Return true if this is a smallvector which has not had dynamic
84 /// memory allocated for it.
85 bool isSmall() const {
86 return BeginX == static_cast<const void*>(&FirstEl);
89 /// Put this vector in a state of being small.
91 BeginX = EndX = CapacityX = &FirstEl;
94 void setEnd(T *P) { this->EndX = P; }
96 typedef size_t size_type;
97 typedef ptrdiff_t difference_type;
100 typedef const T *const_iterator;
102 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
103 typedef std::reverse_iterator<iterator> reverse_iterator;
105 typedef T &reference;
106 typedef const T &const_reference;
108 typedef const T *const_pointer;
110 // forward iterator creation methods.
111 iterator begin() { return (iterator)this->BeginX; }
112 const_iterator begin() const { return (const_iterator)this->BeginX; }
113 iterator end() { return (iterator)this->EndX; }
114 const_iterator end() const { return (const_iterator)this->EndX; }
116 iterator capacity_ptr() { return (iterator)this->CapacityX; }
117 const_iterator capacity_ptr() const { return (const_iterator)this->CapacityX;}
120 // reverse iterator creation methods.
121 reverse_iterator rbegin() { return reverse_iterator(end()); }
122 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
123 reverse_iterator rend() { return reverse_iterator(begin()); }
124 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
126 size_type size() const { return end()-begin(); }
127 size_type max_size() const { return size_type(-1) / sizeof(T); }
129 /// Return the total number of elements in the currently allocated buffer.
130 size_t capacity() const { return capacity_ptr() - begin(); }
132 /// Return a pointer to the vector's buffer, even if empty().
133 pointer data() { return pointer(begin()); }
134 /// Return a pointer to the vector's buffer, even if empty().
135 const_pointer data() const { return const_pointer(begin()); }
137 reference operator[](size_type idx) {
138 assert(idx < size());
141 const_reference operator[](size_type idx) const {
142 assert(idx < size());
150 const_reference front() const {
159 const_reference back() const {
165 /// SmallVectorTemplateBase<isPodLike = false> - This is where we put method
166 /// implementations that are designed to work with non-POD-like T's.
167 template <typename T, bool isPodLike>
168 class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
170 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
172 static void destroy_range(T *S, T *E) {
179 /// Use move-assignment to move the range [I, E) onto the
180 /// objects starting with "Dest". This is just <memory>'s
181 /// std::move, but not all stdlibs actually provide that.
182 template<typename It1, typename It2>
183 static It2 move(It1 I, It1 E, It2 Dest) {
184 for (; I != E; ++I, ++Dest)
185 *Dest = ::std::move(*I);
189 /// Use move-assignment to move the range
190 /// [I, E) onto the objects ending at "Dest", moving objects
191 /// in reverse order. This is just <algorithm>'s
192 /// std::move_backward, but not all stdlibs actually provide that.
193 template<typename It1, typename It2>
194 static It2 move_backward(It1 I, It1 E, It2 Dest) {
196 *--Dest = ::std::move(*--E);
200 /// Move the range [I, E) into the uninitialized memory starting with "Dest",
201 /// constructing elements as needed.
202 template<typename It1, typename It2>
203 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
204 for (; I != E; ++I, ++Dest)
205 ::new ((void*) &*Dest) T(::std::move(*I));
208 /// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
209 /// constructing elements as needed.
210 template<typename It1, typename It2>
211 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
212 std::uninitialized_copy(I, E, Dest);
215 /// Grow the allocated memory (without initializing new elements), doubling
216 /// the size of the allocated memory. Guarantees space for at least one more
217 /// element, or MinSize more elements if specified.
218 void grow(size_t MinSize = 0);
221 void push_back(const T &Elt) {
222 if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
224 ::new ((void*) this->end()) T(Elt);
225 this->setEnd(this->end()+1);
228 void push_back(T &&Elt) {
229 if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
231 ::new ((void*) this->end()) T(::std::move(Elt));
232 this->setEnd(this->end()+1);
236 this->setEnd(this->end()-1);
241 // Define this out-of-line to dissuade the C++ compiler from inlining it.
242 template <typename T, bool isPodLike>
243 void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
244 size_t CurCapacity = this->capacity();
245 size_t CurSize = this->size();
246 // Always grow, even from zero.
247 size_t NewCapacity = size_t(NextPowerOf2(CurCapacity+2));
248 if (NewCapacity < MinSize)
249 NewCapacity = MinSize;
250 T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
252 // Move the elements over.
253 this->uninitialized_move(this->begin(), this->end(), NewElts);
255 // Destroy the original elements.
256 destroy_range(this->begin(), this->end());
258 // If this wasn't grown from the inline copy, deallocate the old space.
259 if (!this->isSmall())
262 this->setEnd(NewElts+CurSize);
263 this->BeginX = NewElts;
264 this->CapacityX = this->begin()+NewCapacity;
268 /// SmallVectorTemplateBase<isPodLike = true> - This is where we put method
269 /// implementations that are designed to work with POD-like T's.
270 template <typename T>
271 class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
273 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
275 // No need to do a destroy loop for POD's.
276 static void destroy_range(T *, T *) {}
278 /// Use move-assignment to move the range [I, E) onto the
279 /// objects starting with "Dest". For PODs, this is just memcpy.
280 template<typename It1, typename It2>
281 static It2 move(It1 I, It1 E, It2 Dest) {
282 return ::std::copy(I, E, Dest);
285 /// Use move-assignment to move the range [I, E) onto the objects ending at
286 /// "Dest", moving objects in reverse order.
287 template<typename It1, typename It2>
288 static It2 move_backward(It1 I, It1 E, It2 Dest) {
289 return ::std::copy_backward(I, E, Dest);
292 /// Move the range [I, E) onto the uninitialized memory
293 /// starting with "Dest", constructing elements into it as needed.
294 template<typename It1, typename It2>
295 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
297 uninitialized_copy(I, E, Dest);
300 /// Copy the range [I, E) onto the uninitialized memory
301 /// starting with "Dest", constructing elements into it as needed.
302 template<typename It1, typename It2>
303 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
304 // Arbitrary iterator types; just use the basic implementation.
305 std::uninitialized_copy(I, E, Dest);
308 /// Copy the range [I, E) onto the uninitialized memory
309 /// starting with "Dest", constructing elements into it as needed.
310 template <typename T1, typename T2>
311 static void uninitialized_copy(
312 T1 *I, T1 *E, T2 *Dest,
313 typename std::enable_if<std::is_same<typename std::remove_const<T1>::type,
314 T2>::value>::type * = nullptr) {
315 // Use memcpy for PODs iterated by pointers (which includes SmallVector
316 // iterators): std::uninitialized_copy optimizes to memmove, but we can
318 memcpy(Dest, I, (E-I)*sizeof(T));
321 /// Double the size of the allocated memory, guaranteeing space for at
322 /// least one more element or MinSize if specified.
323 void grow(size_t MinSize = 0) {
324 this->grow_pod(MinSize*sizeof(T), sizeof(T));
327 void push_back(const T &Elt) {
328 if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
330 memcpy(this->end(), &Elt, sizeof(T));
331 this->setEnd(this->end()+1);
335 this->setEnd(this->end()-1);
340 /// This class consists of common code factored out of the SmallVector class to
341 /// reduce code duplication based on the SmallVector 'N' template parameter.
342 template <typename T>
343 class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> {
344 typedef SmallVectorTemplateBase<T, isPodLike<T>::value > SuperClass;
346 SmallVectorImpl(const SmallVectorImpl&) LLVM_DELETED_FUNCTION;
348 typedef typename SuperClass::iterator iterator;
349 typedef typename SuperClass::size_type size_type;
352 // Default ctor - Initialize to empty.
353 explicit SmallVectorImpl(unsigned N)
354 : SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) {
359 // Destroy the constructed elements in the vector.
360 this->destroy_range(this->begin(), this->end());
362 // If this wasn't grown from the inline copy, deallocate the old space.
363 if (!this->isSmall())
369 this->destroy_range(this->begin(), this->end());
370 this->EndX = this->BeginX;
373 void resize(size_type N) {
374 if (N < this->size()) {
375 this->destroy_range(this->begin()+N, this->end());
376 this->setEnd(this->begin()+N);
377 } else if (N > this->size()) {
378 if (this->capacity() < N)
380 for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
382 this->setEnd(this->begin()+N);
386 void resize(size_type N, const T &NV) {
387 if (N < this->size()) {
388 this->destroy_range(this->begin()+N, this->end());
389 this->setEnd(this->begin()+N);
390 } else if (N > this->size()) {
391 if (this->capacity() < N)
393 std::uninitialized_fill(this->end(), this->begin()+N, NV);
394 this->setEnd(this->begin()+N);
398 void reserve(size_type N) {
399 if (this->capacity() < N)
403 T LLVM_ATTRIBUTE_UNUSED_RESULT pop_back_val() {
404 T Result = ::std::move(this->back());
409 void swap(SmallVectorImpl &RHS);
411 /// Add the specified range to the end of the SmallVector.
412 template<typename in_iter>
413 void append(in_iter in_start, in_iter in_end) {
414 size_type NumInputs = std::distance(in_start, in_end);
415 // Grow allocated space if needed.
416 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
417 this->grow(this->size()+NumInputs);
419 // Copy the new elements over.
420 this->uninitialized_copy(in_start, in_end, this->end());
421 this->setEnd(this->end() + NumInputs);
424 /// Add the specified range to the end of the SmallVector.
425 void append(size_type NumInputs, const T &Elt) {
426 // Grow allocated space if needed.
427 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
428 this->grow(this->size()+NumInputs);
430 // Copy the new elements over.
431 std::uninitialized_fill_n(this->end(), NumInputs, Elt);
432 this->setEnd(this->end() + NumInputs);
435 void assign(size_type NumElts, const T &Elt) {
437 if (this->capacity() < NumElts)
439 this->setEnd(this->begin()+NumElts);
440 std::uninitialized_fill(this->begin(), this->end(), Elt);
443 iterator erase(iterator I) {
444 assert(I >= this->begin() && "Iterator to erase is out of bounds.");
445 assert(I < this->end() && "Erasing at past-the-end iterator.");
448 // Shift all elts down one.
449 this->move(I+1, this->end(), I);
450 // Drop the last elt.
455 iterator erase(iterator S, iterator E) {
456 assert(S >= this->begin() && "Range to erase is out of bounds.");
457 assert(S <= E && "Trying to erase invalid range.");
458 assert(E <= this->end() && "Trying to erase past the end.");
461 // Shift all elts down.
462 iterator I = this->move(E, this->end(), S);
463 // Drop the last elts.
464 this->destroy_range(I, this->end());
469 iterator insert(iterator I, T &&Elt) {
470 if (I == this->end()) { // Important special case for empty vector.
471 this->push_back(::std::move(Elt));
472 return this->end()-1;
475 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
476 assert(I <= this->end() && "Inserting past the end of the vector.");
478 if (this->EndX >= this->CapacityX) {
479 size_t EltNo = I-this->begin();
481 I = this->begin()+EltNo;
484 ::new ((void*) this->end()) T(::std::move(this->back()));
485 // Push everything else over.
486 this->move_backward(I, this->end()-1, this->end());
487 this->setEnd(this->end()+1);
489 // If we just moved the element we're inserting, be sure to update
492 if (I <= EltPtr && EltPtr < this->EndX)
495 *I = ::std::move(*EltPtr);
499 iterator insert(iterator I, const T &Elt) {
500 if (I == this->end()) { // Important special case for empty vector.
501 this->push_back(Elt);
502 return this->end()-1;
505 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
506 assert(I <= this->end() && "Inserting past the end of the vector.");
508 if (this->EndX >= this->CapacityX) {
509 size_t EltNo = I-this->begin();
511 I = this->begin()+EltNo;
513 ::new ((void*) this->end()) T(std::move(this->back()));
514 // Push everything else over.
515 this->move_backward(I, this->end()-1, this->end());
516 this->setEnd(this->end()+1);
518 // If we just moved the element we're inserting, be sure to update
520 const T *EltPtr = &Elt;
521 if (I <= EltPtr && EltPtr < this->EndX)
528 iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
529 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
530 size_t InsertElt = I - this->begin();
532 if (I == this->end()) { // Important special case for empty vector.
533 append(NumToInsert, Elt);
534 return this->begin()+InsertElt;
537 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
538 assert(I <= this->end() && "Inserting past the end of the vector.");
540 // Ensure there is enough space.
541 reserve(this->size() + NumToInsert);
543 // Uninvalidate the iterator.
544 I = this->begin()+InsertElt;
546 // If there are more elements between the insertion point and the end of the
547 // range than there are being inserted, we can use a simple approach to
548 // insertion. Since we already reserved space, we know that this won't
549 // reallocate the vector.
550 if (size_t(this->end()-I) >= NumToInsert) {
551 T *OldEnd = this->end();
552 append(std::move_iterator<iterator>(this->end() - NumToInsert),
553 std::move_iterator<iterator>(this->end()));
555 // Copy the existing elements that get replaced.
556 this->move_backward(I, OldEnd-NumToInsert, OldEnd);
558 std::fill_n(I, NumToInsert, Elt);
562 // Otherwise, we're inserting more elements than exist already, and we're
563 // not inserting at the end.
565 // Move over the elements that we're about to overwrite.
566 T *OldEnd = this->end();
567 this->setEnd(this->end() + NumToInsert);
568 size_t NumOverwritten = OldEnd-I;
569 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
571 // Replace the overwritten part.
572 std::fill_n(I, NumOverwritten, Elt);
574 // Insert the non-overwritten middle part.
575 std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
579 template<typename ItTy>
580 iterator insert(iterator I, ItTy From, ItTy To) {
581 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
582 size_t InsertElt = I - this->begin();
584 if (I == this->end()) { // Important special case for empty vector.
586 return this->begin()+InsertElt;
589 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
590 assert(I <= this->end() && "Inserting past the end of the vector.");
592 size_t NumToInsert = std::distance(From, To);
594 // Ensure there is enough space.
595 reserve(this->size() + NumToInsert);
597 // Uninvalidate the iterator.
598 I = this->begin()+InsertElt;
600 // If there are more elements between the insertion point and the end of the
601 // range than there are being inserted, we can use a simple approach to
602 // insertion. Since we already reserved space, we know that this won't
603 // reallocate the vector.
604 if (size_t(this->end()-I) >= NumToInsert) {
605 T *OldEnd = this->end();
606 append(std::move_iterator<iterator>(this->end() - NumToInsert),
607 std::move_iterator<iterator>(this->end()));
609 // Copy the existing elements that get replaced.
610 this->move_backward(I, OldEnd-NumToInsert, OldEnd);
612 std::copy(From, To, I);
616 // Otherwise, we're inserting more elements than exist already, and we're
617 // not inserting at the end.
619 // Move over the elements that we're about to overwrite.
620 T *OldEnd = this->end();
621 this->setEnd(this->end() + NumToInsert);
622 size_t NumOverwritten = OldEnd-I;
623 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
625 // Replace the overwritten part.
626 for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
631 // Insert the non-overwritten middle part.
632 this->uninitialized_copy(From, To, OldEnd);
636 template <typename... ArgTypes> void emplace_back(ArgTypes &&... Args) {
637 if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
639 ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
640 this->setEnd(this->end() + 1);
643 SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
645 SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
647 bool operator==(const SmallVectorImpl &RHS) const {
648 if (this->size() != RHS.size()) return false;
649 return std::equal(this->begin(), this->end(), RHS.begin());
651 bool operator!=(const SmallVectorImpl &RHS) const {
652 return !(*this == RHS);
655 bool operator<(const SmallVectorImpl &RHS) const {
656 return std::lexicographical_compare(this->begin(), this->end(),
657 RHS.begin(), RHS.end());
660 /// Set the array size to \p N, which the current array must have enough
663 /// This does not construct or destroy any elements in the vector.
665 /// Clients can use this in conjunction with capacity() to write past the end
666 /// of the buffer when they know that more elements are available, and only
667 /// update the size later. This avoids the cost of value initializing elements
668 /// which will only be overwritten.
669 void set_size(size_type N) {
670 assert(N <= this->capacity());
671 this->setEnd(this->begin() + N);
676 template <typename T>
677 void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
678 if (this == &RHS) return;
680 // We can only avoid copying elements if neither vector is small.
681 if (!this->isSmall() && !RHS.isSmall()) {
682 std::swap(this->BeginX, RHS.BeginX);
683 std::swap(this->EndX, RHS.EndX);
684 std::swap(this->CapacityX, RHS.CapacityX);
687 if (RHS.size() > this->capacity())
688 this->grow(RHS.size());
689 if (this->size() > RHS.capacity())
690 RHS.grow(this->size());
692 // Swap the shared elements.
693 size_t NumShared = this->size();
694 if (NumShared > RHS.size()) NumShared = RHS.size();
695 for (size_type i = 0; i != NumShared; ++i)
696 std::swap((*this)[i], RHS[i]);
698 // Copy over the extra elts.
699 if (this->size() > RHS.size()) {
700 size_t EltDiff = this->size() - RHS.size();
701 this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
702 RHS.setEnd(RHS.end()+EltDiff);
703 this->destroy_range(this->begin()+NumShared, this->end());
704 this->setEnd(this->begin()+NumShared);
705 } else if (RHS.size() > this->size()) {
706 size_t EltDiff = RHS.size() - this->size();
707 this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
708 this->setEnd(this->end() + EltDiff);
709 this->destroy_range(RHS.begin()+NumShared, RHS.end());
710 RHS.setEnd(RHS.begin()+NumShared);
714 template <typename T>
715 SmallVectorImpl<T> &SmallVectorImpl<T>::
716 operator=(const SmallVectorImpl<T> &RHS) {
717 // Avoid self-assignment.
718 if (this == &RHS) return *this;
720 // If we already have sufficient space, assign the common elements, then
721 // destroy any excess.
722 size_t RHSSize = RHS.size();
723 size_t CurSize = this->size();
724 if (CurSize >= RHSSize) {
725 // Assign common elements.
728 NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
730 NewEnd = this->begin();
732 // Destroy excess elements.
733 this->destroy_range(NewEnd, this->end());
736 this->setEnd(NewEnd);
740 // If we have to grow to have enough elements, destroy the current elements.
741 // This allows us to avoid copying them during the grow.
742 // FIXME: don't do this if they're efficiently moveable.
743 if (this->capacity() < RHSSize) {
744 // Destroy current elements.
745 this->destroy_range(this->begin(), this->end());
746 this->setEnd(this->begin());
749 } else if (CurSize) {
750 // Otherwise, use assignment for the already-constructed elements.
751 std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
754 // Copy construct the new elements in place.
755 this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
756 this->begin()+CurSize);
759 this->setEnd(this->begin()+RHSSize);
763 template <typename T>
764 SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
765 // Avoid self-assignment.
766 if (this == &RHS) return *this;
768 // If the RHS isn't small, clear this vector and then steal its buffer.
769 if (!RHS.isSmall()) {
770 this->destroy_range(this->begin(), this->end());
771 if (!this->isSmall()) free(this->begin());
772 this->BeginX = RHS.BeginX;
773 this->EndX = RHS.EndX;
774 this->CapacityX = RHS.CapacityX;
779 // If we already have sufficient space, assign the common elements, then
780 // destroy any excess.
781 size_t RHSSize = RHS.size();
782 size_t CurSize = this->size();
783 if (CurSize >= RHSSize) {
784 // Assign common elements.
785 iterator NewEnd = this->begin();
787 NewEnd = this->move(RHS.begin(), RHS.end(), NewEnd);
789 // Destroy excess elements and trim the bounds.
790 this->destroy_range(NewEnd, this->end());
791 this->setEnd(NewEnd);
799 // If we have to grow to have enough elements, destroy the current elements.
800 // This allows us to avoid copying them during the grow.
801 // FIXME: this may not actually make any sense if we can efficiently move
803 if (this->capacity() < RHSSize) {
804 // Destroy current elements.
805 this->destroy_range(this->begin(), this->end());
806 this->setEnd(this->begin());
809 } else if (CurSize) {
810 // Otherwise, use assignment for the already-constructed elements.
811 this->move(RHS.begin(), RHS.begin()+CurSize, this->begin());
814 // Move-construct the new elements in place.
815 this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
816 this->begin()+CurSize);
819 this->setEnd(this->begin()+RHSSize);
825 /// Storage for the SmallVector elements which aren't contained in
826 /// SmallVectorTemplateCommon. There are 'N-1' elements here. The remaining '1'
827 /// element is in the base class. This is specialized for the N=1 and N=0 cases
828 /// to avoid allocating unnecessary storage.
829 template <typename T, unsigned N>
830 struct SmallVectorStorage {
831 typename SmallVectorTemplateCommon<T>::U InlineElts[N - 1];
833 template <typename T> struct SmallVectorStorage<T, 1> {};
834 template <typename T> struct SmallVectorStorage<T, 0> {};
836 /// This is a 'vector' (really, a variable-sized array), optimized
837 /// for the case when the array is small. It contains some number of elements
838 /// in-place, which allows it to avoid heap allocation when the actual number of
839 /// elements is below that threshold. This allows normal "small" cases to be
840 /// fast without losing generality for large inputs.
842 /// Note that this does not attempt to be exception safe.
844 template <typename T, unsigned N>
845 class SmallVector : public SmallVectorImpl<T> {
846 /// Inline space for elements which aren't stored in the base class.
847 SmallVectorStorage<T, N> Storage;
849 SmallVector() : SmallVectorImpl<T>(N) {
852 explicit SmallVector(size_t Size, const T &Value = T())
853 : SmallVectorImpl<T>(N) {
854 this->assign(Size, Value);
857 template<typename ItTy>
858 SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
862 template <typename RangeTy>
863 explicit SmallVector(const llvm::iterator_range<RangeTy> R)
864 : SmallVectorImpl<T>(N) {
865 this->append(R.begin(), R.end());
868 SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
870 SmallVectorImpl<T>::operator=(RHS);
873 const SmallVector &operator=(const SmallVector &RHS) {
874 SmallVectorImpl<T>::operator=(RHS);
878 SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
880 SmallVectorImpl<T>::operator=(::std::move(RHS));
883 const SmallVector &operator=(SmallVector &&RHS) {
884 SmallVectorImpl<T>::operator=(::std::move(RHS));
888 SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
890 SmallVectorImpl<T>::operator=(::std::move(RHS));
893 const SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
894 SmallVectorImpl<T>::operator=(::std::move(RHS));
900 template<typename T, unsigned N>
901 static inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
902 return X.capacity_in_bytes();
905 } // End llvm namespace
908 /// Implement std::swap in terms of SmallVector swap.
911 swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
915 /// Implement std::swap in terms of SmallVector swap.
916 template<typename T, unsigned N>
918 swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {