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 /// SmallVectorBase - This is all the non-templated stuff common to all
34 class SmallVectorBase {
36 void *BeginX, *EndX, *CapacityX;
39 SmallVectorBase(void *FirstEl, size_t Size)
40 : BeginX(FirstEl), EndX(FirstEl), CapacityX((char*)FirstEl+Size) {}
42 /// grow_pod - 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);
47 /// size_in_bytes - This returns size()*sizeof(T).
48 size_t size_in_bytes() const {
49 return size_t((char*)EndX - (char*)BeginX);
52 /// capacity_in_bytes - This returns capacity()*sizeof(T).
53 size_t capacity_in_bytes() const {
54 return size_t((char*)CapacityX - (char*)BeginX);
57 bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const { return BeginX == EndX; }
60 template <typename T, unsigned N> struct SmallVectorStorage;
62 /// SmallVectorTemplateCommon - This is the part of SmallVectorTemplateBase
63 /// which does not depend on whether the type T is a POD. The extra dummy
64 /// template argument is used by ArrayRef to avoid unnecessarily requiring T
66 template <typename T, typename = void>
67 class SmallVectorTemplateCommon : public SmallVectorBase {
69 template <typename, unsigned> friend struct SmallVectorStorage;
71 // Allocate raw space for N elements of type T. If T has a ctor or dtor, we
72 // don't want it to be automatically run, so we need to represent the space as
73 // something else. Use an array of char of sufficient alignment.
74 typedef llvm::AlignedCharArrayUnion<T> U;
76 // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
79 SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(&FirstEl, Size) {}
81 void grow_pod(size_t MinSizeInBytes, size_t TSize) {
82 SmallVectorBase::grow_pod(&FirstEl, MinSizeInBytes, TSize);
85 /// isSmall - Return true if this is a smallvector which has not had dynamic
86 /// memory allocated for it.
87 bool isSmall() const {
88 return BeginX == static_cast<const void*>(&FirstEl);
91 /// resetToSmall - Put this vector in a state of being small.
93 BeginX = EndX = CapacityX = &FirstEl;
96 void setEnd(T *P) { this->EndX = P; }
98 typedef size_t size_type;
99 typedef ptrdiff_t difference_type;
100 typedef T value_type;
102 typedef const T *const_iterator;
104 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
105 typedef std::reverse_iterator<iterator> reverse_iterator;
107 typedef T &reference;
108 typedef const T &const_reference;
110 typedef const T *const_pointer;
112 // forward iterator creation methods.
113 iterator begin() { return (iterator)this->BeginX; }
114 const_iterator begin() const { return (const_iterator)this->BeginX; }
115 iterator end() { return (iterator)this->EndX; }
116 const_iterator end() const { return (const_iterator)this->EndX; }
118 iterator capacity_ptr() { return (iterator)this->CapacityX; }
119 const_iterator capacity_ptr() const { return (const_iterator)this->CapacityX;}
122 // reverse iterator creation methods.
123 reverse_iterator rbegin() { return reverse_iterator(end()); }
124 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
125 reverse_iterator rend() { return reverse_iterator(begin()); }
126 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
128 size_type size() const { return end()-begin(); }
129 size_type max_size() const { return size_type(-1) / sizeof(T); }
131 /// capacity - Return the total number of elements in the currently allocated
133 size_t capacity() const { return capacity_ptr() - begin(); }
135 /// data - Return a pointer to the vector's buffer, even if empty().
136 pointer data() { return pointer(begin()); }
137 /// data - Return a pointer to the vector's buffer, even if empty().
138 const_pointer data() const { return const_pointer(begin()); }
140 reference operator[](unsigned idx) {
141 assert(begin() + idx < end());
144 const_reference operator[](unsigned idx) const {
145 assert(begin() + idx < end());
153 const_reference front() const {
162 const_reference back() const {
168 /// SmallVectorTemplateBase<isPodLike = false> - This is where we put method
169 /// implementations that are designed to work with non-POD-like T's.
170 template <typename T, bool isPodLike>
171 class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
173 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
175 static void destroy_range(T *S, T *E) {
182 /// move - Use move-assignment to move the range [I, E) onto the
183 /// objects starting with "Dest". This is just <memory>'s
184 /// std::move, but not all stdlibs actually provide that.
185 template<typename It1, typename It2>
186 static It2 move(It1 I, It1 E, It2 Dest) {
187 for (; I != E; ++I, ++Dest)
188 *Dest = ::std::move(*I);
192 /// move_backward - Use move-assignment to move the range
193 /// [I, E) onto the objects ending at "Dest", moving objects
194 /// in reverse order. This is just <algorithm>'s
195 /// std::move_backward, but not all stdlibs actually provide that.
196 template<typename It1, typename It2>
197 static It2 move_backward(It1 I, It1 E, It2 Dest) {
199 *--Dest = ::std::move(*--E);
203 /// uninitialized_move - Move the range [I, E) into the uninitialized
204 /// memory starting with "Dest", constructing elements as needed.
205 template<typename It1, typename It2>
206 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
207 for (; I != E; ++I, ++Dest)
208 ::new ((void*) &*Dest) T(::std::move(*I));
211 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized
212 /// memory starting with "Dest", constructing elements as needed.
213 template<typename It1, typename It2>
214 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
215 std::uninitialized_copy(I, E, Dest);
218 /// grow - Grow the allocated memory (without initializing new
219 /// elements), doubling the size of the allocated memory.
220 /// Guarantees space for at least one more element, or MinSize more
221 /// elements if specified.
222 void grow(size_t MinSize = 0);
225 void push_back(const T &Elt) {
226 if (this->EndX < this->CapacityX) {
228 ::new ((void*) this->end()) T(Elt);
229 this->setEnd(this->end()+1);
236 void push_back(T &&Elt) {
237 if (this->EndX < this->CapacityX) {
239 ::new ((void*) this->end()) T(::std::move(Elt));
240 this->setEnd(this->end()+1);
248 this->setEnd(this->end()-1);
253 // Define this out-of-line to dissuade the C++ compiler from inlining it.
254 template <typename T, bool isPodLike>
255 void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
256 size_t CurCapacity = this->capacity();
257 size_t CurSize = this->size();
258 // Always grow, even from zero.
259 size_t NewCapacity = size_t(NextPowerOf2(CurCapacity+2));
260 if (NewCapacity < MinSize)
261 NewCapacity = MinSize;
262 T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
264 // Move the elements over.
265 this->uninitialized_move(this->begin(), this->end(), NewElts);
267 // Destroy the original elements.
268 destroy_range(this->begin(), this->end());
270 // If this wasn't grown from the inline copy, deallocate the old space.
271 if (!this->isSmall())
274 this->setEnd(NewElts+CurSize);
275 this->BeginX = NewElts;
276 this->CapacityX = this->begin()+NewCapacity;
280 /// SmallVectorTemplateBase<isPodLike = true> - This is where we put method
281 /// implementations that are designed to work with POD-like T's.
282 template <typename T>
283 class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
285 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
287 // No need to do a destroy loop for POD's.
288 static void destroy_range(T *, T *) {}
290 /// move - Use move-assignment to move the range [I, E) onto the
291 /// objects starting with "Dest". For PODs, this is just memcpy.
292 template<typename It1, typename It2>
293 static It2 move(It1 I, It1 E, It2 Dest) {
294 return ::std::copy(I, E, Dest);
297 /// move_backward - Use move-assignment to move the range
298 /// [I, E) onto the objects ending at "Dest", moving objects
299 /// in reverse order.
300 template<typename It1, typename It2>
301 static It2 move_backward(It1 I, It1 E, It2 Dest) {
302 return ::std::copy_backward(I, E, Dest);
305 /// uninitialized_move - Move the range [I, E) onto the uninitialized memory
306 /// starting with "Dest", constructing elements into it as needed.
307 template<typename It1, typename It2>
308 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
310 uninitialized_copy(I, E, Dest);
313 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
314 /// starting with "Dest", constructing elements into it as needed.
315 template<typename It1, typename It2>
316 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
317 // Arbitrary iterator types; just use the basic implementation.
318 std::uninitialized_copy(I, E, Dest);
321 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
322 /// starting with "Dest", constructing elements into it as needed.
323 template<typename T1, typename T2>
324 static void uninitialized_copy(T1 *I, T1 *E, T2 *Dest) {
325 // Use memcpy for PODs iterated by pointers (which includes SmallVector
326 // iterators): std::uninitialized_copy optimizes to memmove, but we can
328 memcpy(Dest, I, (E-I)*sizeof(T));
331 /// grow - double the size of the allocated memory, guaranteeing space for at
332 /// least one more element or MinSize if specified.
333 void grow(size_t MinSize = 0) {
334 this->grow_pod(MinSize*sizeof(T), sizeof(T));
337 void push_back(const T &Elt) {
338 if (this->EndX < this->CapacityX) {
340 memcpy(this->end(), &Elt, sizeof(T));
341 this->setEnd(this->end()+1);
349 this->setEnd(this->end()-1);
354 /// SmallVectorImpl - This class consists of common code factored out of the
355 /// SmallVector class to reduce code duplication based on the SmallVector 'N'
356 /// template parameter.
357 template <typename T>
358 class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> {
359 typedef SmallVectorTemplateBase<T, isPodLike<T>::value > SuperClass;
361 SmallVectorImpl(const SmallVectorImpl&) LLVM_DELETED_FUNCTION;
363 typedef typename SuperClass::iterator iterator;
364 typedef typename SuperClass::size_type size_type;
367 // Default ctor - Initialize to empty.
368 explicit SmallVectorImpl(unsigned N)
369 : SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) {
374 // Destroy the constructed elements in the vector.
375 this->destroy_range(this->begin(), this->end());
377 // If this wasn't grown from the inline copy, deallocate the old space.
378 if (!this->isSmall())
384 this->destroy_range(this->begin(), this->end());
385 this->EndX = this->BeginX;
388 void resize(unsigned N) {
389 if (N < this->size()) {
390 this->destroy_range(this->begin()+N, this->end());
391 this->setEnd(this->begin()+N);
392 } else if (N > this->size()) {
393 if (this->capacity() < N)
395 std::uninitialized_fill(this->end(), this->begin()+N, T());
396 this->setEnd(this->begin()+N);
400 void resize(unsigned N, const T &NV) {
401 if (N < this->size()) {
402 this->destroy_range(this->begin()+N, this->end());
403 this->setEnd(this->begin()+N);
404 } else if (N > this->size()) {
405 if (this->capacity() < N)
407 std::uninitialized_fill(this->end(), this->begin()+N, NV);
408 this->setEnd(this->begin()+N);
412 void reserve(unsigned N) {
413 if (this->capacity() < N)
417 T LLVM_ATTRIBUTE_UNUSED_RESULT pop_back_val() {
418 T Result = ::std::move(this->back());
423 void swap(SmallVectorImpl &RHS);
425 /// append - Add the specified range to the end of the SmallVector.
427 template<typename in_iter>
428 void append(in_iter in_start, in_iter in_end) {
429 size_type NumInputs = std::distance(in_start, in_end);
430 // Grow allocated space if needed.
431 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
432 this->grow(this->size()+NumInputs);
434 // Copy the new elements over.
435 // TODO: NEED To compile time dispatch on whether in_iter is a random access
436 // iterator to use the fast uninitialized_copy.
437 std::uninitialized_copy(in_start, in_end, this->end());
438 this->setEnd(this->end() + NumInputs);
441 /// append - Add the specified range to the end of the SmallVector.
443 void append(size_type NumInputs, const T &Elt) {
444 // Grow allocated space if needed.
445 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
446 this->grow(this->size()+NumInputs);
448 // Copy the new elements over.
449 std::uninitialized_fill_n(this->end(), NumInputs, Elt);
450 this->setEnd(this->end() + NumInputs);
453 void assign(unsigned NumElts, const T &Elt) {
455 if (this->capacity() < NumElts)
457 this->setEnd(this->begin()+NumElts);
458 std::uninitialized_fill(this->begin(), this->end(), Elt);
461 iterator erase(iterator I) {
462 assert(I >= this->begin() && "Iterator to erase is out of bounds.");
463 assert(I < this->end() && "Erasing at past-the-end iterator.");
466 // Shift all elts down one.
467 this->move(I+1, this->end(), I);
468 // Drop the last elt.
473 iterator erase(iterator S, iterator E) {
474 assert(S >= this->begin() && "Range to erase is out of bounds.");
475 assert(S <= E && "Trying to erase invalid range.");
476 assert(E <= this->end() && "Trying to erase past the end.");
479 // Shift all elts down.
480 iterator I = this->move(E, this->end(), S);
481 // Drop the last elts.
482 this->destroy_range(I, this->end());
487 iterator insert(iterator I, T &&Elt) {
488 if (I == this->end()) { // Important special case for empty vector.
489 this->push_back(::std::move(Elt));
490 return this->end()-1;
493 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
494 assert(I <= this->end() && "Inserting past the end of the vector.");
496 if (this->EndX < this->CapacityX) {
498 ::new ((void*) this->end()) T(::std::move(this->back()));
499 this->setEnd(this->end()+1);
500 // Push everything else over.
501 this->move_backward(I, this->end()-1, this->end());
503 // If we just moved the element we're inserting, be sure to update
506 if (I <= EltPtr && EltPtr < this->EndX)
509 *I = ::std::move(*EltPtr);
512 size_t EltNo = I-this->begin();
514 I = this->begin()+EltNo;
518 iterator insert(iterator I, const T &Elt) {
519 if (I == this->end()) { // Important special case for empty vector.
520 this->push_back(Elt);
521 return this->end()-1;
524 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
525 assert(I <= this->end() && "Inserting past the end of the vector.");
527 if (this->EndX < this->CapacityX) {
529 ::new ((void*) this->end()) T(this->back());
530 this->setEnd(this->end()+1);
531 // Push everything else over.
532 this->move_backward(I, this->end()-1, this->end());
534 // If we just moved the element we're inserting, be sure to update
536 const T *EltPtr = &Elt;
537 if (I <= EltPtr && EltPtr < this->EndX)
543 size_t EltNo = I-this->begin();
545 I = this->begin()+EltNo;
549 iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
550 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
551 size_t InsertElt = I - this->begin();
553 if (I == this->end()) { // Important special case for empty vector.
554 append(NumToInsert, Elt);
555 return this->begin()+InsertElt;
558 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
559 assert(I <= this->end() && "Inserting past the end of the vector.");
561 // Ensure there is enough space.
562 reserve(static_cast<unsigned>(this->size() + NumToInsert));
564 // Uninvalidate the iterator.
565 I = this->begin()+InsertElt;
567 // If there are more elements between the insertion point and the end of the
568 // range than there are being inserted, we can use a simple approach to
569 // insertion. Since we already reserved space, we know that this won't
570 // reallocate the vector.
571 if (size_t(this->end()-I) >= NumToInsert) {
572 T *OldEnd = this->end();
573 append(this->end()-NumToInsert, this->end());
575 // Copy the existing elements that get replaced.
576 this->move_backward(I, OldEnd-NumToInsert, OldEnd);
578 std::fill_n(I, NumToInsert, Elt);
582 // Otherwise, we're inserting more elements than exist already, and we're
583 // not inserting at the end.
585 // Move over the elements that we're about to overwrite.
586 T *OldEnd = this->end();
587 this->setEnd(this->end() + NumToInsert);
588 size_t NumOverwritten = OldEnd-I;
589 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
591 // Replace the overwritten part.
592 std::fill_n(I, NumOverwritten, Elt);
594 // Insert the non-overwritten middle part.
595 std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
599 template<typename ItTy>
600 iterator insert(iterator I, ItTy From, ItTy To) {
601 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
602 size_t InsertElt = I - this->begin();
604 if (I == this->end()) { // Important special case for empty vector.
606 return this->begin()+InsertElt;
609 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
610 assert(I <= this->end() && "Inserting past the end of the vector.");
612 size_t NumToInsert = std::distance(From, To);
614 // Ensure there is enough space.
615 reserve(static_cast<unsigned>(this->size() + NumToInsert));
617 // Uninvalidate the iterator.
618 I = this->begin()+InsertElt;
620 // If there are more elements between the insertion point and the end of the
621 // range than there are being inserted, we can use a simple approach to
622 // insertion. Since we already reserved space, we know that this won't
623 // reallocate the vector.
624 if (size_t(this->end()-I) >= NumToInsert) {
625 T *OldEnd = this->end();
626 append(this->end()-NumToInsert, this->end());
628 // Copy the existing elements that get replaced.
629 this->move_backward(I, OldEnd-NumToInsert, OldEnd);
631 std::copy(From, To, I);
635 // Otherwise, we're inserting more elements than exist already, and we're
636 // not inserting at the end.
638 // Move over the elements that we're about to overwrite.
639 T *OldEnd = this->end();
640 this->setEnd(this->end() + NumToInsert);
641 size_t NumOverwritten = OldEnd-I;
642 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
644 // Replace the overwritten part.
645 for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
650 // Insert the non-overwritten middle part.
651 this->uninitialized_copy(From, To, OldEnd);
655 SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
657 SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
659 bool operator==(const SmallVectorImpl &RHS) const {
660 if (this->size() != RHS.size()) return false;
661 return std::equal(this->begin(), this->end(), RHS.begin());
663 bool operator!=(const SmallVectorImpl &RHS) const {
664 return !(*this == RHS);
667 bool operator<(const SmallVectorImpl &RHS) const {
668 return std::lexicographical_compare(this->begin(), this->end(),
669 RHS.begin(), RHS.end());
672 /// Set the array size to \p N, which the current array must have enough
675 /// This does not construct or destroy any elements in the vector.
677 /// Clients can use this in conjunction with capacity() to write past the end
678 /// of the buffer when they know that more elements are available, and only
679 /// update the size later. This avoids the cost of value initializing elements
680 /// which will only be overwritten.
681 void set_size(unsigned N) {
682 assert(N <= this->capacity());
683 this->setEnd(this->begin() + N);
688 template <typename T>
689 void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
690 if (this == &RHS) return;
692 // We can only avoid copying elements if neither vector is small.
693 if (!this->isSmall() && !RHS.isSmall()) {
694 std::swap(this->BeginX, RHS.BeginX);
695 std::swap(this->EndX, RHS.EndX);
696 std::swap(this->CapacityX, RHS.CapacityX);
699 if (RHS.size() > this->capacity())
700 this->grow(RHS.size());
701 if (this->size() > RHS.capacity())
702 RHS.grow(this->size());
704 // Swap the shared elements.
705 size_t NumShared = this->size();
706 if (NumShared > RHS.size()) NumShared = RHS.size();
707 for (unsigned i = 0; i != static_cast<unsigned>(NumShared); ++i)
708 std::swap((*this)[i], RHS[i]);
710 // Copy over the extra elts.
711 if (this->size() > RHS.size()) {
712 size_t EltDiff = this->size() - RHS.size();
713 this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
714 RHS.setEnd(RHS.end()+EltDiff);
715 this->destroy_range(this->begin()+NumShared, this->end());
716 this->setEnd(this->begin()+NumShared);
717 } else if (RHS.size() > this->size()) {
718 size_t EltDiff = RHS.size() - this->size();
719 this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
720 this->setEnd(this->end() + EltDiff);
721 this->destroy_range(RHS.begin()+NumShared, RHS.end());
722 RHS.setEnd(RHS.begin()+NumShared);
726 template <typename T>
727 SmallVectorImpl<T> &SmallVectorImpl<T>::
728 operator=(const SmallVectorImpl<T> &RHS) {
729 // Avoid self-assignment.
730 if (this == &RHS) return *this;
732 // If we already have sufficient space, assign the common elements, then
733 // destroy any excess.
734 size_t RHSSize = RHS.size();
735 size_t CurSize = this->size();
736 if (CurSize >= RHSSize) {
737 // Assign common elements.
740 NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
742 NewEnd = this->begin();
744 // Destroy excess elements.
745 this->destroy_range(NewEnd, this->end());
748 this->setEnd(NewEnd);
752 // If we have to grow to have enough elements, destroy the current elements.
753 // This allows us to avoid copying them during the grow.
754 // FIXME: don't do this if they're efficiently moveable.
755 if (this->capacity() < RHSSize) {
756 // Destroy current elements.
757 this->destroy_range(this->begin(), this->end());
758 this->setEnd(this->begin());
761 } else if (CurSize) {
762 // Otherwise, use assignment for the already-constructed elements.
763 std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
766 // Copy construct the new elements in place.
767 this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
768 this->begin()+CurSize);
771 this->setEnd(this->begin()+RHSSize);
775 template <typename T>
776 SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
777 // Avoid self-assignment.
778 if (this == &RHS) return *this;
780 // If the RHS isn't small, clear this vector and then steal its buffer.
781 if (!RHS.isSmall()) {
782 this->destroy_range(this->begin(), this->end());
783 if (!this->isSmall()) free(this->begin());
784 this->BeginX = RHS.BeginX;
785 this->EndX = RHS.EndX;
786 this->CapacityX = RHS.CapacityX;
791 // If we already have sufficient space, assign the common elements, then
792 // destroy any excess.
793 size_t RHSSize = RHS.size();
794 size_t CurSize = this->size();
795 if (CurSize >= RHSSize) {
796 // Assign common elements.
797 iterator NewEnd = this->begin();
799 NewEnd = this->move(RHS.begin(), RHS.end(), NewEnd);
801 // Destroy excess elements and trim the bounds.
802 this->destroy_range(NewEnd, this->end());
803 this->setEnd(NewEnd);
811 // If we have to grow to have enough elements, destroy the current elements.
812 // This allows us to avoid copying them during the grow.
813 // FIXME: this may not actually make any sense if we can efficiently move
815 if (this->capacity() < RHSSize) {
816 // Destroy current elements.
817 this->destroy_range(this->begin(), this->end());
818 this->setEnd(this->begin());
821 } else if (CurSize) {
822 // Otherwise, use assignment for the already-constructed elements.
823 this->move(RHS.begin(), RHS.end(), this->begin());
826 // Move-construct the new elements in place.
827 this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
828 this->begin()+CurSize);
831 this->setEnd(this->begin()+RHSSize);
837 /// Storage for the SmallVector elements which aren't contained in
838 /// SmallVectorTemplateCommon. There are 'N-1' elements here. The remaining '1'
839 /// element is in the base class. This is specialized for the N=1 and N=0 cases
840 /// to avoid allocating unnecessary storage.
841 template <typename T, unsigned N>
842 struct SmallVectorStorage {
843 typename SmallVectorTemplateCommon<T>::U InlineElts[N - 1];
845 template <typename T> struct SmallVectorStorage<T, 1> {};
846 template <typename T> struct SmallVectorStorage<T, 0> {};
848 /// SmallVector - This is a 'vector' (really, a variable-sized array), optimized
849 /// for the case when the array is small. It contains some number of elements
850 /// in-place, which allows it to avoid heap allocation when the actual number of
851 /// elements is below that threshold. This allows normal "small" cases to be
852 /// fast without losing generality for large inputs.
854 /// Note that this does not attempt to be exception safe.
856 template <typename T, unsigned N>
857 class SmallVector : public SmallVectorImpl<T> {
858 /// Storage - Inline space for elements which aren't stored in the base class.
859 SmallVectorStorage<T, N> Storage;
861 SmallVector() : SmallVectorImpl<T>(N) {
864 explicit SmallVector(unsigned Size, const T &Value = T())
865 : SmallVectorImpl<T>(N) {
866 this->assign(Size, Value);
869 template<typename ItTy>
870 SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
874 template <typename RangeTy>
875 explicit SmallVector(const llvm::iterator_range<RangeTy> R)
876 : SmallVectorImpl<T>(N) {
877 this->append(R.begin(), R.end());
880 SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
882 SmallVectorImpl<T>::operator=(RHS);
885 const SmallVector &operator=(const SmallVector &RHS) {
886 SmallVectorImpl<T>::operator=(RHS);
890 SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
892 SmallVectorImpl<T>::operator=(::std::move(RHS));
895 const SmallVector &operator=(SmallVector &&RHS) {
896 SmallVectorImpl<T>::operator=(::std::move(RHS));
901 template<typename T, unsigned N>
902 static inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
903 return X.capacity_in_bytes();
906 } // End llvm namespace
909 /// Implement std::swap in terms of SmallVector swap.
912 swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
916 /// Implement std::swap in terms of SmallVector swap.
917 template<typename T, unsigned N>
919 swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {