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/Support/AlignOf.h"
18 #include "llvm/Support/Compiler.h"
19 #include "llvm/Support/MathExtras.h"
20 #include "llvm/Support/type_traits.h"
31 /// SmallVectorBase - This is all the non-templated stuff common to all
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 /// grow_pod - 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 /// size_in_bytes - 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 /// SmallVectorTemplateCommon - This is the part of SmallVectorTemplateBase
62 /// which does not depend on whether the type T is a POD. The extra dummy
63 /// template argument is used by ArrayRef to avoid unnecessarily requiring T
65 template <typename T, typename = void>
66 class SmallVectorTemplateCommon : public SmallVectorBase {
68 template <typename, unsigned> friend struct SmallVectorStorage;
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;
75 // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
78 SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(&FirstEl, Size) {}
80 void grow_pod(size_t MinSizeInBytes, size_t TSize) {
81 SmallVectorBase::grow_pod(&FirstEl, MinSizeInBytes, TSize);
84 /// isSmall - Return true if this is a smallvector which has not had dynamic
85 /// memory allocated for it.
86 bool isSmall() const {
87 return BeginX == static_cast<const void*>(&FirstEl);
90 /// resetToSmall - Put this vector in a state of being small.
92 BeginX = EndX = CapacityX = &FirstEl;
95 void setEnd(T *P) { this->EndX = P; }
97 typedef size_t size_type;
98 typedef ptrdiff_t difference_type;
101 typedef const T *const_iterator;
103 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
104 typedef std::reverse_iterator<iterator> reverse_iterator;
106 typedef T &reference;
107 typedef const T &const_reference;
109 typedef const T *const_pointer;
111 // forward iterator creation methods.
112 iterator begin() { return (iterator)this->BeginX; }
113 const_iterator begin() const { return (const_iterator)this->BeginX; }
114 iterator end() { return (iterator)this->EndX; }
115 const_iterator end() const { return (const_iterator)this->EndX; }
117 iterator capacity_ptr() { return (iterator)this->CapacityX; }
118 const_iterator capacity_ptr() const { return (const_iterator)this->CapacityX;}
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());}
127 size_type size() const { return end()-begin(); }
128 size_type max_size() const { return size_type(-1) / sizeof(T); }
130 /// capacity - Return the total number of elements in the currently allocated
132 size_t capacity() const { return capacity_ptr() - begin(); }
134 /// data - Return a pointer to the vector's buffer, even if empty().
135 pointer data() { return pointer(begin()); }
136 /// data - Return a pointer to the vector's buffer, even if empty().
137 const_pointer data() const { return const_pointer(begin()); }
139 reference operator[](unsigned idx) {
140 assert(begin() + idx < end());
143 const_reference operator[](unsigned idx) const {
144 assert(begin() + idx < end());
152 const_reference front() const {
161 const_reference back() const {
167 /// SmallVectorTemplateBase<isPodLike = false> - This is where we put method
168 /// implementations that are designed to work with non-POD-like T's.
169 template <typename T, bool isPodLike>
170 class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
172 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
174 static void destroy_range(T *S, T *E) {
181 /// move - Use move-assignment to move the range [I, E) onto the
182 /// objects starting with "Dest". This is just <memory>'s
183 /// std::move, but not all stdlibs actually provide that.
184 template<typename It1, typename It2>
185 static It2 move(It1 I, It1 E, It2 Dest) {
186 #if LLVM_HAS_RVALUE_REFERENCES
187 for (; I != E; ++I, ++Dest)
188 *Dest = ::std::move(*I);
191 return ::std::copy(I, E, Dest);
195 /// move_backward - Use move-assignment to move the range
196 /// [I, E) onto the objects ending at "Dest", moving objects
197 /// in reverse order. This is just <algorithm>'s
198 /// std::move_backward, but not all stdlibs actually provide that.
199 template<typename It1, typename It2>
200 static It2 move_backward(It1 I, It1 E, It2 Dest) {
201 #if LLVM_HAS_RVALUE_REFERENCES
203 *--Dest = ::std::move(*--E);
206 return ::std::copy_backward(I, E, Dest);
210 /// uninitialized_move - Move the range [I, E) into the uninitialized
211 /// memory starting with "Dest", constructing elements as needed.
212 template<typename It1, typename It2>
213 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
214 #if LLVM_HAS_RVALUE_REFERENCES
215 for (; I != E; ++I, ++Dest)
216 ::new ((void*) &*Dest) T(::std::move(*I));
218 ::std::uninitialized_copy(I, E, Dest);
222 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized
223 /// memory starting with "Dest", constructing elements as needed.
224 template<typename It1, typename It2>
225 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
226 std::uninitialized_copy(I, E, Dest);
229 /// grow - Grow the allocated memory (without initializing new
230 /// elements), doubling the size of the allocated memory.
231 /// Guarantees space for at least one more element, or MinSize more
232 /// elements if specified.
233 void grow(size_t MinSize = 0);
236 void push_back(const T &Elt) {
237 if (this->EndX < this->CapacityX) {
239 ::new ((void*) this->end()) T(Elt);
240 this->setEnd(this->end()+1);
247 #if LLVM_HAS_RVALUE_REFERENCES
248 void push_back(T &&Elt) {
249 if (this->EndX < this->CapacityX) {
251 ::new ((void*) this->end()) T(::std::move(Elt));
252 this->setEnd(this->end()+1);
261 this->setEnd(this->end()-1);
266 // Define this out-of-line to dissuade the C++ compiler from inlining it.
267 template <typename T, bool isPodLike>
268 void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
269 size_t CurCapacity = this->capacity();
270 size_t CurSize = this->size();
271 // Always grow, even from zero.
272 size_t NewCapacity = size_t(NextPowerOf2(CurCapacity+2));
273 if (NewCapacity < MinSize)
274 NewCapacity = MinSize;
275 T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
277 // Move the elements over.
278 this->uninitialized_move(this->begin(), this->end(), NewElts);
280 // Destroy the original elements.
281 destroy_range(this->begin(), this->end());
283 // If this wasn't grown from the inline copy, deallocate the old space.
284 if (!this->isSmall())
287 this->setEnd(NewElts+CurSize);
288 this->BeginX = NewElts;
289 this->CapacityX = this->begin()+NewCapacity;
293 /// SmallVectorTemplateBase<isPodLike = true> - This is where we put method
294 /// implementations that are designed to work with POD-like T's.
295 template <typename T>
296 class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
298 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
300 // No need to do a destroy loop for POD's.
301 static void destroy_range(T *, T *) {}
303 /// move - Use move-assignment to move the range [I, E) onto the
304 /// objects starting with "Dest". For PODs, this is just memcpy.
305 template<typename It1, typename It2>
306 static It2 move(It1 I, It1 E, It2 Dest) {
307 return ::std::copy(I, E, Dest);
310 /// move_backward - Use move-assignment to move the range
311 /// [I, E) onto the objects ending at "Dest", moving objects
312 /// in reverse order.
313 template<typename It1, typename It2>
314 static It2 move_backward(It1 I, It1 E, It2 Dest) {
315 return ::std::copy_backward(I, E, Dest);
318 /// uninitialized_move - Move the range [I, E) onto the uninitialized memory
319 /// starting with "Dest", constructing elements into it as needed.
320 template<typename It1, typename It2>
321 static void uninitialized_move(It1 I, It1 E, It2 Dest) {
323 uninitialized_copy(I, E, Dest);
326 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
327 /// starting with "Dest", constructing elements into it as needed.
328 template<typename It1, typename It2>
329 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
330 // Arbitrary iterator types; just use the basic implementation.
331 std::uninitialized_copy(I, E, Dest);
334 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
335 /// starting with "Dest", constructing elements into it as needed.
336 template<typename T1, typename T2>
337 static void uninitialized_copy(T1 *I, T1 *E, T2 *Dest) {
338 // Use memcpy for PODs iterated by pointers (which includes SmallVector
339 // iterators): std::uninitialized_copy optimizes to memmove, but we can
341 memcpy(Dest, I, (E-I)*sizeof(T));
344 /// grow - double the size of the allocated memory, guaranteeing space for at
345 /// least one more element or MinSize if specified.
346 void grow(size_t MinSize = 0) {
347 this->grow_pod(MinSize*sizeof(T), sizeof(T));
350 void push_back(const T &Elt) {
351 if (this->EndX < this->CapacityX) {
353 memcpy(this->end(), &Elt, sizeof(T));
354 this->setEnd(this->end()+1);
362 this->setEnd(this->end()-1);
367 /// SmallVectorImpl - This class consists of common code factored out of the
368 /// SmallVector class to reduce code duplication based on the SmallVector 'N'
369 /// template parameter.
370 template <typename T>
371 class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> {
372 typedef SmallVectorTemplateBase<T, isPodLike<T>::value > SuperClass;
374 SmallVectorImpl(const SmallVectorImpl&) LLVM_DELETED_FUNCTION;
376 typedef typename SuperClass::iterator iterator;
377 typedef typename SuperClass::size_type size_type;
380 // Default ctor - Initialize to empty.
381 explicit SmallVectorImpl(unsigned N)
382 : SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) {
387 // Destroy the constructed elements in the vector.
388 this->destroy_range(this->begin(), this->end());
390 // If this wasn't grown from the inline copy, deallocate the old space.
391 if (!this->isSmall())
397 this->destroy_range(this->begin(), this->end());
398 this->EndX = this->BeginX;
401 void resize(unsigned N) {
402 if (N < this->size()) {
403 this->destroy_range(this->begin()+N, this->end());
404 this->setEnd(this->begin()+N);
405 } else if (N > this->size()) {
406 if (this->capacity() < N)
408 std::uninitialized_fill(this->end(), this->begin()+N, T());
409 this->setEnd(this->begin()+N);
413 void resize(unsigned N, const T &NV) {
414 if (N < this->size()) {
415 this->destroy_range(this->begin()+N, this->end());
416 this->setEnd(this->begin()+N);
417 } else if (N > this->size()) {
418 if (this->capacity() < N)
420 std::uninitialized_fill(this->end(), this->begin()+N, NV);
421 this->setEnd(this->begin()+N);
425 void reserve(unsigned N) {
426 if (this->capacity() < N)
430 T LLVM_ATTRIBUTE_UNUSED_RESULT pop_back_val() {
431 #if LLVM_HAS_RVALUE_REFERENCES
432 T Result = ::std::move(this->back());
434 T Result = this->back();
440 void swap(SmallVectorImpl &RHS);
442 /// append - Add the specified range to the end of the SmallVector.
444 template<typename in_iter>
445 void append(in_iter in_start, in_iter in_end) {
446 size_type NumInputs = std::distance(in_start, in_end);
447 // Grow allocated space if needed.
448 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
449 this->grow(this->size()+NumInputs);
451 // Copy the new elements over.
452 // TODO: NEED To compile time dispatch on whether in_iter is a random access
453 // iterator to use the fast uninitialized_copy.
454 std::uninitialized_copy(in_start, in_end, this->end());
455 this->setEnd(this->end() + NumInputs);
458 /// append - Add the specified range to the end of the SmallVector.
460 void append(size_type NumInputs, const T &Elt) {
461 // Grow allocated space if needed.
462 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
463 this->grow(this->size()+NumInputs);
465 // Copy the new elements over.
466 std::uninitialized_fill_n(this->end(), NumInputs, Elt);
467 this->setEnd(this->end() + NumInputs);
470 void assign(unsigned NumElts, const T &Elt) {
472 if (this->capacity() < NumElts)
474 this->setEnd(this->begin()+NumElts);
475 std::uninitialized_fill(this->begin(), this->end(), Elt);
478 iterator erase(iterator I) {
479 assert(I >= this->begin() && "Iterator to erase is out of bounds.");
480 assert(I < this->end() && "Erasing at past-the-end iterator.");
483 // Shift all elts down one.
484 this->move(I+1, this->end(), I);
485 // Drop the last elt.
490 iterator erase(iterator S, iterator E) {
491 assert(S >= this->begin() && "Range to erase is out of bounds.");
492 assert(S <= E && "Trying to erase invalid range.");
493 assert(E <= this->end() && "Trying to erase past the end.");
496 // Shift all elts down.
497 iterator I = this->move(E, this->end(), S);
498 // Drop the last elts.
499 this->destroy_range(I, this->end());
504 #if LLVM_HAS_RVALUE_REFERENCES
505 iterator insert(iterator I, T &&Elt) {
506 if (I == this->end()) { // Important special case for empty vector.
507 this->push_back(::std::move(Elt));
508 return this->end()-1;
511 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
512 assert(I <= this->end() && "Inserting past the end of the vector.");
514 if (this->EndX < this->CapacityX) {
516 ::new ((void*) this->end()) T(::std::move(this->back()));
517 this->setEnd(this->end()+1);
518 // Push everything else over.
519 this->move_backward(I, this->end()-1, this->end());
521 // If we just moved the element we're inserting, be sure to update
524 if (I <= EltPtr && EltPtr < this->EndX)
527 *I = ::std::move(*EltPtr);
530 size_t EltNo = I-this->begin();
532 I = this->begin()+EltNo;
537 iterator insert(iterator I, const T &Elt) {
538 if (I == this->end()) { // Important special case for empty vector.
539 this->push_back(Elt);
540 return this->end()-1;
543 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
544 assert(I <= this->end() && "Inserting past the end of the vector.");
546 if (this->EndX < this->CapacityX) {
548 ::new ((void*) this->end()) T(this->back());
549 this->setEnd(this->end()+1);
550 // Push everything else over.
551 this->move_backward(I, this->end()-1, this->end());
553 // If we just moved the element we're inserting, be sure to update
555 const T *EltPtr = &Elt;
556 if (I <= EltPtr && EltPtr < this->EndX)
562 size_t EltNo = I-this->begin();
564 I = this->begin()+EltNo;
568 iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
569 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
570 size_t InsertElt = I - this->begin();
572 if (I == this->end()) { // Important special case for empty vector.
573 append(NumToInsert, Elt);
574 return this->begin()+InsertElt;
577 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
578 assert(I <= this->end() && "Inserting past the end of the vector.");
580 // Ensure there is enough space.
581 reserve(static_cast<unsigned>(this->size() + NumToInsert));
583 // Uninvalidate the iterator.
584 I = this->begin()+InsertElt;
586 // If there are more elements between the insertion point and the end of the
587 // range than there are being inserted, we can use a simple approach to
588 // insertion. Since we already reserved space, we know that this won't
589 // reallocate the vector.
590 if (size_t(this->end()-I) >= NumToInsert) {
591 T *OldEnd = this->end();
592 append(this->end()-NumToInsert, this->end());
594 // Copy the existing elements that get replaced.
595 this->move_backward(I, OldEnd-NumToInsert, OldEnd);
597 std::fill_n(I, NumToInsert, Elt);
601 // Otherwise, we're inserting more elements than exist already, and we're
602 // not inserting at the end.
604 // Move over the elements that we're about to overwrite.
605 T *OldEnd = this->end();
606 this->setEnd(this->end() + NumToInsert);
607 size_t NumOverwritten = OldEnd-I;
608 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
610 // Replace the overwritten part.
611 std::fill_n(I, NumOverwritten, Elt);
613 // Insert the non-overwritten middle part.
614 std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
618 template<typename ItTy>
619 iterator insert(iterator I, ItTy From, ItTy To) {
620 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
621 size_t InsertElt = I - this->begin();
623 if (I == this->end()) { // Important special case for empty vector.
625 return this->begin()+InsertElt;
628 assert(I >= this->begin() && "Insertion iterator is out of bounds.");
629 assert(I <= this->end() && "Inserting past the end of the vector.");
631 size_t NumToInsert = std::distance(From, To);
633 // Ensure there is enough space.
634 reserve(static_cast<unsigned>(this->size() + NumToInsert));
636 // Uninvalidate the iterator.
637 I = this->begin()+InsertElt;
639 // If there are more elements between the insertion point and the end of the
640 // range than there are being inserted, we can use a simple approach to
641 // insertion. Since we already reserved space, we know that this won't
642 // reallocate the vector.
643 if (size_t(this->end()-I) >= NumToInsert) {
644 T *OldEnd = this->end();
645 append(this->end()-NumToInsert, this->end());
647 // Copy the existing elements that get replaced.
648 this->move_backward(I, OldEnd-NumToInsert, OldEnd);
650 std::copy(From, To, I);
654 // Otherwise, we're inserting more elements than exist already, and we're
655 // not inserting at the end.
657 // Move over the elements that we're about to overwrite.
658 T *OldEnd = this->end();
659 this->setEnd(this->end() + NumToInsert);
660 size_t NumOverwritten = OldEnd-I;
661 this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
663 // Replace the overwritten part.
664 for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
669 // Insert the non-overwritten middle part.
670 this->uninitialized_copy(From, To, OldEnd);
674 SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
676 #if LLVM_HAS_RVALUE_REFERENCES
677 SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
680 bool operator==(const SmallVectorImpl &RHS) const {
681 if (this->size() != RHS.size()) return false;
682 return std::equal(this->begin(), this->end(), RHS.begin());
684 bool operator!=(const SmallVectorImpl &RHS) const {
685 return !(*this == RHS);
688 bool operator<(const SmallVectorImpl &RHS) const {
689 return std::lexicographical_compare(this->begin(), this->end(),
690 RHS.begin(), RHS.end());
693 /// Set the array size to \p N, which the current array must have enough
696 /// This does not construct or destroy any elements in the vector.
698 /// Clients can use this in conjunction with capacity() to write past the end
699 /// of the buffer when they know that more elements are available, and only
700 /// update the size later. This avoids the cost of value initializing elements
701 /// which will only be overwritten.
702 void set_size(unsigned N) {
703 assert(N <= this->capacity());
704 this->setEnd(this->begin() + N);
709 template <typename T>
710 void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
711 if (this == &RHS) return;
713 // We can only avoid copying elements if neither vector is small.
714 if (!this->isSmall() && !RHS.isSmall()) {
715 std::swap(this->BeginX, RHS.BeginX);
716 std::swap(this->EndX, RHS.EndX);
717 std::swap(this->CapacityX, RHS.CapacityX);
720 if (RHS.size() > this->capacity())
721 this->grow(RHS.size());
722 if (this->size() > RHS.capacity())
723 RHS.grow(this->size());
725 // Swap the shared elements.
726 size_t NumShared = this->size();
727 if (NumShared > RHS.size()) NumShared = RHS.size();
728 for (unsigned i = 0; i != static_cast<unsigned>(NumShared); ++i)
729 std::swap((*this)[i], RHS[i]);
731 // Copy over the extra elts.
732 if (this->size() > RHS.size()) {
733 size_t EltDiff = this->size() - RHS.size();
734 this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
735 RHS.setEnd(RHS.end()+EltDiff);
736 this->destroy_range(this->begin()+NumShared, this->end());
737 this->setEnd(this->begin()+NumShared);
738 } else if (RHS.size() > this->size()) {
739 size_t EltDiff = RHS.size() - this->size();
740 this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
741 this->setEnd(this->end() + EltDiff);
742 this->destroy_range(RHS.begin()+NumShared, RHS.end());
743 RHS.setEnd(RHS.begin()+NumShared);
747 template <typename T>
748 SmallVectorImpl<T> &SmallVectorImpl<T>::
749 operator=(const SmallVectorImpl<T> &RHS) {
750 // Avoid self-assignment.
751 if (this == &RHS) return *this;
753 // If we already have sufficient space, assign the common elements, then
754 // destroy any excess.
755 size_t RHSSize = RHS.size();
756 size_t CurSize = this->size();
757 if (CurSize >= RHSSize) {
758 // Assign common elements.
761 NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
763 NewEnd = this->begin();
765 // Destroy excess elements.
766 this->destroy_range(NewEnd, this->end());
769 this->setEnd(NewEnd);
773 // If we have to grow to have enough elements, destroy the current elements.
774 // This allows us to avoid copying them during the grow.
775 // FIXME: don't do this if they're efficiently moveable.
776 if (this->capacity() < RHSSize) {
777 // Destroy current elements.
778 this->destroy_range(this->begin(), this->end());
779 this->setEnd(this->begin());
782 } else if (CurSize) {
783 // Otherwise, use assignment for the already-constructed elements.
784 std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
787 // Copy construct the new elements in place.
788 this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(),
789 this->begin()+CurSize);
792 this->setEnd(this->begin()+RHSSize);
796 #if LLVM_HAS_RVALUE_REFERENCES
797 template <typename T>
798 SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
799 // Avoid self-assignment.
800 if (this == &RHS) return *this;
802 // If the RHS isn't small, clear this vector and then steal its buffer.
803 if (!RHS.isSmall()) {
804 this->destroy_range(this->begin(), this->end());
805 if (!this->isSmall()) free(this->begin());
806 this->BeginX = RHS.BeginX;
807 this->EndX = RHS.EndX;
808 this->CapacityX = RHS.CapacityX;
813 // If we already have sufficient space, assign the common elements, then
814 // destroy any excess.
815 size_t RHSSize = RHS.size();
816 size_t CurSize = this->size();
817 if (CurSize >= RHSSize) {
818 // Assign common elements.
819 iterator NewEnd = this->begin();
821 NewEnd = this->move(RHS.begin(), RHS.end(), NewEnd);
823 // Destroy excess elements and trim the bounds.
824 this->destroy_range(NewEnd, this->end());
825 this->setEnd(NewEnd);
833 // If we have to grow to have enough elements, destroy the current elements.
834 // This allows us to avoid copying them during the grow.
835 // FIXME: this may not actually make any sense if we can efficiently move
837 if (this->capacity() < RHSSize) {
838 // Destroy current elements.
839 this->destroy_range(this->begin(), this->end());
840 this->setEnd(this->begin());
843 } else if (CurSize) {
844 // Otherwise, use assignment for the already-constructed elements.
845 this->move(RHS.begin(), RHS.end(), this->begin());
848 // Move-construct the new elements in place.
849 this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
850 this->begin()+CurSize);
853 this->setEnd(this->begin()+RHSSize);
860 /// Storage for the SmallVector elements which aren't contained in
861 /// SmallVectorTemplateCommon. There are 'N-1' elements here. The remaining '1'
862 /// element is in the base class. This is specialized for the N=1 and N=0 cases
863 /// to avoid allocating unnecessary storage.
864 template <typename T, unsigned N>
865 struct SmallVectorStorage {
866 typename SmallVectorTemplateCommon<T>::U InlineElts[N - 1];
868 template <typename T> struct SmallVectorStorage<T, 1> {};
869 template <typename T> struct SmallVectorStorage<T, 0> {};
871 /// SmallVector - This is a 'vector' (really, a variable-sized array), optimized
872 /// for the case when the array is small. It contains some number of elements
873 /// in-place, which allows it to avoid heap allocation when the actual number of
874 /// elements is below that threshold. This allows normal "small" cases to be
875 /// fast without losing generality for large inputs.
877 /// Note that this does not attempt to be exception safe.
879 template <typename T, unsigned N>
880 class SmallVector : public SmallVectorImpl<T> {
881 /// Storage - Inline space for elements which aren't stored in the base class.
882 SmallVectorStorage<T, N> Storage;
884 SmallVector() : SmallVectorImpl<T>(N) {
887 explicit SmallVector(unsigned Size, const T &Value = T())
888 : SmallVectorImpl<T>(N) {
889 this->assign(Size, Value);
892 template<typename ItTy>
893 SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
897 SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
899 SmallVectorImpl<T>::operator=(RHS);
902 const SmallVector &operator=(const SmallVector &RHS) {
903 SmallVectorImpl<T>::operator=(RHS);
907 #if LLVM_HAS_RVALUE_REFERENCES
908 SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
910 SmallVectorImpl<T>::operator=(::std::move(RHS));
913 const SmallVector &operator=(SmallVector &&RHS) {
914 SmallVectorImpl<T>::operator=(::std::move(RHS));
921 template<typename T, unsigned N>
922 static inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
923 return X.capacity_in_bytes();
926 } // End llvm namespace
929 /// Implement std::swap in terms of SmallVector swap.
932 swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
936 /// Implement std::swap in terms of SmallVector swap.
937 template<typename T, unsigned N>
939 swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {