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/type_traits.h"
26 // Work around flawed VC++ implementation of std::uninitialized_copy. Define
27 // additional overloads so that elements with pointer types are recognized as
28 // scalars and not objects, causing bizarre type conversion errors.
29 template<class T1, class T2>
30 inline _Scalar_ptr_iterator_tag _Ptr_cat(T1 **, T2 **) {
31 _Scalar_ptr_iterator_tag _Cat;
35 template<class T1, class T2>
36 inline _Scalar_ptr_iterator_tag _Ptr_cat(T1* const *, T2 **) {
37 _Scalar_ptr_iterator_tag _Cat;
41 // FIXME: It is not clear if the problem is fixed in VS 2005. What is clear
42 // is that the above hack won't work if it wasn't fixed.
49 /// SmallVectorBase - This is all the non-templated stuff common to all
51 class SmallVectorBase {
53 void *BeginX, *EndX, *CapacityX;
55 // Allocate raw space for N elements of type T. If T has a ctor or dtor, we
56 // don't want it to be automatically run, so we need to represent the space as
57 // something else. An array of char would work great, but might not be
58 // aligned sufficiently. Instead, we either use GCC extensions, or some
59 // number of union instances for the space, which guarantee maximal alignment.
62 U FirstEl __attribute__((aligned));
71 // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
74 SmallVectorBase(size_t Size)
75 : BeginX(&FirstEl), EndX(&FirstEl), CapacityX((char*)&FirstEl+Size) {}
77 /// isSmall - Return true if this is a smallvector which has not had dynamic
78 /// memory allocated for it.
79 bool isSmall() const {
80 return BeginX == static_cast<const void*>(&FirstEl);
83 /// size_in_bytes - This returns size()*sizeof(T).
84 size_t size_in_bytes() const {
85 return size_t((char*)EndX - (char*)BeginX);
88 /// capacity_in_bytes - This returns capacity()*sizeof(T).
89 size_t capacity_in_bytes() const {
90 return size_t((char*)CapacityX - (char*)BeginX);
93 inline void grow_pod(size_t MinSizeInBytes, size_t TSize);
96 bool empty() const { return BeginX == EndX; }
99 inline void SmallVectorBase::grow_pod(size_t MinSizeInBytes, size_t TSize) {
100 size_t CurSizeBytes = size_in_bytes();
101 size_t NewCapacityInBytes = 2 * capacity_in_bytes();
102 if (NewCapacityInBytes < MinSizeInBytes)
103 NewCapacityInBytes = MinSizeInBytes;
104 void *NewElts = operator new(NewCapacityInBytes);
106 // Copy the elements over.
107 memcpy(NewElts, this->BeginX, CurSizeBytes);
109 // If this wasn't grown from the inline copy, deallocate the old space.
110 if (!this->isSmall())
111 operator delete(this->BeginX);
113 this->EndX = (char*)NewElts+CurSizeBytes;
114 this->BeginX = NewElts;
115 this->CapacityX = (char*)this->BeginX + NewCapacityInBytes;
120 template <typename T>
121 class SmallVectorTemplateCommon : public SmallVectorBase {
123 void setEnd(T *P) { this->EndX = P; }
125 SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(Size) {}
127 typedef size_t size_type;
128 typedef ptrdiff_t difference_type;
129 typedef T value_type;
131 typedef const T *const_iterator;
133 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
134 typedef std::reverse_iterator<iterator> reverse_iterator;
136 typedef T &reference;
137 typedef const T &const_reference;
139 typedef const T *const_pointer;
141 // forward iterator creation methods.
142 iterator begin() { return (iterator)this->BeginX; }
143 const_iterator begin() const { return (const_iterator)this->BeginX; }
144 iterator end() { return (iterator)this->EndX; }
145 const_iterator end() const { return (const_iterator)this->EndX; }
147 iterator capacity_ptr() { return (iterator)this->CapacityX; }
148 const_iterator capacity_ptr() const { return (const_iterator)this->CapacityX;}
151 // reverse iterator creation methods.
152 reverse_iterator rbegin() { return reverse_iterator(end()); }
153 const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); }
154 reverse_iterator rend() { return reverse_iterator(begin()); }
155 const_reverse_iterator rend() const { return const_reverse_iterator(begin());}
157 size_type size() const { return end()-begin(); }
158 size_type max_size() const { return size_type(-1) / sizeof(T); }
160 /// capacity - Return the total number of elements in the currently allocated
162 size_t capacity() const { return capacity_ptr() - begin(); }
164 /// data - Return a pointer to the vector's buffer, even if empty().
165 pointer data() { return pointer(begin()); }
166 /// data - Return a pointer to the vector's buffer, even if empty().
167 const_pointer data() const { return const_pointer(begin()); }
169 reference operator[](unsigned idx) {
170 assert(begin() + idx < end());
173 const_reference operator[](unsigned idx) const {
174 assert(begin() + idx < end());
181 const_reference front() const {
188 const_reference back() const {
193 /// SmallVectorTemplateBase<isPodLike = false> - This is where we put method
194 /// implementations that are designed to work with non-POD-like T's.
195 template <typename T, bool isPodLike>
196 class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> {
198 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
200 static void destroy_range(T *S, T *E) {
207 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
208 /// starting with "Dest", constructing elements into it as needed.
209 template<typename It1, typename It2>
210 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
211 std::uninitialized_copy(I, E, Dest);
214 /// grow - double the size of the allocated memory, guaranteeing space for at
215 /// least one more element or MinSize if specified.
216 void grow(size_t MinSize = 0);
219 // Define this out-of-line to dissuade the C++ compiler from inlining it.
220 template <typename T, bool isPodLike>
221 void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
222 size_t CurCapacity = this->capacity();
223 size_t CurSize = this->size();
224 size_t NewCapacity = 2*CurCapacity;
225 if (NewCapacity < MinSize)
226 NewCapacity = MinSize;
227 T *NewElts = static_cast<T*>(operator new(NewCapacity*sizeof(T)));
229 // Copy the elements over.
230 uninitialized_copy(this->begin(), this->end(), NewElts);
232 // Destroy the original elements.
233 destroy_range(this->begin(), this->end());
235 // If this wasn't grown from the inline copy, deallocate the old space.
236 if (!this->isSmall())
237 operator delete(this->begin());
239 setEnd(NewElts+CurSize);
240 this->BeginX = NewElts;
241 this->CapacityX = this->begin()+NewCapacity;
245 /// SmallVectorTemplateBase<isPodLike = true> - This is where we put method
246 /// implementations that are designed to work with POD-like T's.
247 template <typename T>
248 class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
250 SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
252 // No need to do a destroy loop for POD's.
253 static void destroy_range(T *S, T *E) {}
255 /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
256 /// starting with "Dest", constructing elements into it as needed.
257 template<typename It1, typename It2>
258 static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
259 // Use memcpy for PODs: std::uninitialized_copy optimizes to memmove, memcpy
261 memcpy(&*Dest, &*I, (E-I)*sizeof(T));
264 /// grow - double the size of the allocated memory, guaranteeing space for at
265 /// least one more element or MinSize if specified.
266 void grow(size_t MinSize = 0) {
267 this->grow_pod(MinSize*sizeof(T), sizeof(T));
272 /// SmallVectorImpl - This class consists of common code factored out of the
273 /// SmallVector class to reduce code duplication based on the SmallVector 'N'
274 /// template parameter.
275 template <typename T>
276 class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> {
277 typedef SmallVectorTemplateBase<T, isPodLike<T>::value > SuperClass;
279 typedef typename SuperClass::iterator iterator;
280 typedef typename SuperClass::size_type size_type;
282 // Default ctor - Initialize to empty.
283 explicit SmallVectorImpl(unsigned N)
284 : SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) {
288 // Destroy the constructed elements in the vector.
289 destroy_range(this->begin(), this->end());
291 // If this wasn't grown from the inline copy, deallocate the old space.
292 if (!this->isSmall())
293 operator delete(this->begin());
298 destroy_range(this->begin(), this->end());
299 this->EndX = this->BeginX;
302 void resize(unsigned N) {
303 if (N < this->size()) {
304 this->destroy_range(this->begin()+N, this->end());
305 this->setEnd(this->begin()+N);
306 } else if (N > this->size()) {
307 if (this->capacity() < N)
309 this->construct_range(this->end(), this->begin()+N, T());
310 this->setEnd(this->begin()+N);
314 void resize(unsigned N, const T &NV) {
315 if (N < this->size()) {
316 destroy_range(this->begin()+N, this->end());
317 setEnd(this->begin()+N);
318 } else if (N > this->size()) {
319 if (this->capacity() < N)
321 construct_range(this->end(), this->begin()+N, NV);
322 setEnd(this->begin()+N);
326 void reserve(unsigned N) {
327 if (this->capacity() < N)
331 void push_back(const T &Elt) {
332 if (this->EndX < this->CapacityX) {
334 new (this->end()) T(Elt);
335 setEnd(this->end()+1);
343 setEnd(this->end()-1);
348 T Result = this->back();
354 void swap(SmallVectorImpl &RHS);
356 /// append - Add the specified range to the end of the SmallVector.
358 template<typename in_iter>
359 void append(in_iter in_start, in_iter in_end) {
360 size_type NumInputs = std::distance(in_start, in_end);
361 // Grow allocated space if needed.
362 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
363 this->grow(this->size()+NumInputs);
365 // Copy the new elements over.
366 // TODO: NEED To compile time dispatch on whether in_iter is a random access
367 // iterator to use the fast uninitialized_copy.
368 std::uninitialized_copy(in_start, in_end, this->end());
369 setEnd(this->end() + NumInputs);
372 /// append - Add the specified range to the end of the SmallVector.
374 void append(size_type NumInputs, const T &Elt) {
375 // Grow allocated space if needed.
376 if (NumInputs > size_type(this->capacity_ptr()-this->end()))
377 this->grow(this->size()+NumInputs);
379 // Copy the new elements over.
380 std::uninitialized_fill_n(this->end(), NumInputs, Elt);
381 setEnd(this->end() + NumInputs);
384 void assign(unsigned NumElts, const T &Elt) {
386 if (this->capacity() < NumElts)
388 setEnd(this->begin()+NumElts);
389 construct_range(this->begin(), this->end(), Elt);
392 iterator erase(iterator I) {
394 // Shift all elts down one.
395 std::copy(I+1, this->end(), I);
396 // Drop the last elt.
401 iterator erase(iterator S, iterator E) {
403 // Shift all elts down.
404 iterator I = std::copy(E, this->end(), S);
405 // Drop the last elts.
406 destroy_range(I, this->end());
411 iterator insert(iterator I, const T &Elt) {
412 if (I == this->end()) { // Important special case for empty vector.
414 return this->end()-1;
417 if (this->EndX < this->CapacityX) {
419 new (this->end()) T(this->back());
420 this->setEnd(this->end()+1);
421 // Push everything else over.
422 std::copy_backward(I, this->end()-1, this->end());
426 size_t EltNo = I-this->begin();
428 I = this->begin()+EltNo;
432 iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
433 if (I == this->end()) { // Important special case for empty vector.
434 append(NumToInsert, Elt);
435 return this->end()-1;
438 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
439 size_t InsertElt = I - this->begin();
441 // Ensure there is enough space.
442 reserve(static_cast<unsigned>(this->size() + NumToInsert));
444 // Uninvalidate the iterator.
445 I = this->begin()+InsertElt;
447 // If there are more elements between the insertion point and the end of the
448 // range than there are being inserted, we can use a simple approach to
449 // insertion. Since we already reserved space, we know that this won't
450 // reallocate the vector.
451 if (size_t(this->end()-I) >= NumToInsert) {
452 T *OldEnd = this->end();
453 append(this->end()-NumToInsert, this->end());
455 // Copy the existing elements that get replaced.
456 std::copy_backward(I, OldEnd-NumToInsert, OldEnd);
458 std::fill_n(I, NumToInsert, Elt);
462 // Otherwise, we're inserting more elements than exist already, and we're
463 // not inserting at the end.
465 // Copy over the elements that we're about to overwrite.
466 T *OldEnd = this->end();
467 setEnd(this->end() + NumToInsert);
468 size_t NumOverwritten = OldEnd-I;
469 uninitialized_copy(I, OldEnd, this->end()-NumOverwritten);
471 // Replace the overwritten part.
472 std::fill_n(I, NumOverwritten, Elt);
474 // Insert the non-overwritten middle part.
475 std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt);
479 template<typename ItTy>
480 iterator insert(iterator I, ItTy From, ItTy To) {
481 if (I == this->end()) { // Important special case for empty vector.
483 return this->end()-1;
486 size_t NumToInsert = std::distance(From, To);
487 // Convert iterator to elt# to avoid invalidating iterator when we reserve()
488 size_t InsertElt = I - this->begin();
490 // Ensure there is enough space.
491 reserve(static_cast<unsigned>(this->size() + NumToInsert));
493 // Uninvalidate the iterator.
494 I = this->begin()+InsertElt;
496 // If there are more elements between the insertion point and the end of the
497 // range than there are being inserted, we can use a simple approach to
498 // insertion. Since we already reserved space, we know that this won't
499 // reallocate the vector.
500 if (size_t(this->end()-I) >= NumToInsert) {
501 T *OldEnd = this->end();
502 append(this->end()-NumToInsert, this->end());
504 // Copy the existing elements that get replaced.
505 std::copy_backward(I, OldEnd-NumToInsert, OldEnd);
507 std::copy(From, To, I);
511 // Otherwise, we're inserting more elements than exist already, and we're
512 // not inserting at the end.
514 // Copy over the elements that we're about to overwrite.
515 T *OldEnd = this->end();
516 setEnd(this->end() + NumToInsert);
517 size_t NumOverwritten = OldEnd-I;
518 uninitialized_copy(I, OldEnd, this->end()-NumOverwritten);
520 // Replace the overwritten part.
521 std::copy(From, From+NumOverwritten, I);
523 // Insert the non-overwritten middle part.
524 uninitialized_copy(From+NumOverwritten, To, OldEnd);
528 const SmallVectorImpl
529 &operator=(const SmallVectorImpl &RHS);
531 bool operator==(const SmallVectorImpl &RHS) const {
532 if (this->size() != RHS.size()) return false;
533 return std::equal(this->begin(), this->end(), RHS.begin());
535 bool operator!=(const SmallVectorImpl &RHS) const {
536 return !(*this == RHS);
539 bool operator<(const SmallVectorImpl &RHS) const {
540 return std::lexicographical_compare(this->begin(), this->end(),
541 RHS.begin(), RHS.end());
544 /// set_size - Set the array size to \arg N, which the current array must have
545 /// enough capacity for.
547 /// This does not construct or destroy any elements in the vector.
549 /// Clients can use this in conjunction with capacity() to write past the end
550 /// of the buffer when they know that more elements are available, and only
551 /// update the size later. This avoids the cost of value initializing elements
552 /// which will only be overwritten.
553 void set_size(unsigned N) {
554 assert(N <= this->capacity());
555 setEnd(this->begin() + N);
559 static void construct_range(T *S, T *E, const T &Elt) {
566 template <typename T>
567 void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
568 if (this == &RHS) return;
570 // We can only avoid copying elements if neither vector is small.
571 if (!this->isSmall() && !RHS.isSmall()) {
572 std::swap(this->BeginX, RHS.BeginX);
573 std::swap(this->EndX, RHS.EndX);
574 std::swap(this->CapacityX, RHS.CapacityX);
577 if (RHS.size() > this->capacity())
578 this->grow(RHS.size());
579 if (this->size() > RHS.capacity())
580 RHS.grow(this->size());
582 // Swap the shared elements.
583 size_t NumShared = this->size();
584 if (NumShared > RHS.size()) NumShared = RHS.size();
585 for (unsigned i = 0; i != static_cast<unsigned>(NumShared); ++i)
586 std::swap((*this)[i], RHS[i]);
588 // Copy over the extra elts.
589 if (this->size() > RHS.size()) {
590 size_t EltDiff = this->size() - RHS.size();
591 uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end());
592 RHS.setEnd(RHS.end()+EltDiff);
593 destroy_range(this->begin()+NumShared, this->end());
594 setEnd(this->begin()+NumShared);
595 } else if (RHS.size() > this->size()) {
596 size_t EltDiff = RHS.size() - this->size();
597 uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end());
598 setEnd(this->end() + EltDiff);
599 destroy_range(RHS.begin()+NumShared, RHS.end());
600 RHS.setEnd(RHS.begin()+NumShared);
604 template <typename T>
605 const SmallVectorImpl<T> &SmallVectorImpl<T>::
606 operator=(const SmallVectorImpl<T> &RHS) {
607 // Avoid self-assignment.
608 if (this == &RHS) return *this;
610 // If we already have sufficient space, assign the common elements, then
611 // destroy any excess.
612 size_t RHSSize = RHS.size();
613 size_t CurSize = this->size();
614 if (CurSize >= RHSSize) {
615 // Assign common elements.
618 NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin());
620 NewEnd = this->begin();
622 // Destroy excess elements.
623 destroy_range(NewEnd, this->end());
630 // If we have to grow to have enough elements, destroy the current elements.
631 // This allows us to avoid copying them during the grow.
632 if (this->capacity() < RHSSize) {
633 // Destroy current elements.
634 destroy_range(this->begin(), this->end());
635 setEnd(this->begin());
638 } else if (CurSize) {
639 // Otherwise, use assignment for the already-constructed elements.
640 std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin());
643 // Copy construct the new elements in place.
644 uninitialized_copy(RHS.begin()+CurSize, RHS.end(), this->begin()+CurSize);
647 setEnd(this->begin()+RHSSize);
652 /// SmallVector - This is a 'vector' (really, a variable-sized array), optimized
653 /// for the case when the array is small. It contains some number of elements
654 /// in-place, which allows it to avoid heap allocation when the actual number of
655 /// elements is below that threshold. This allows normal "small" cases to be
656 /// fast without losing generality for large inputs.
658 /// Note that this does not attempt to be exception safe.
660 template <typename T, unsigned N>
661 class SmallVector : public SmallVectorImpl<T> {
662 /// InlineElts - These are 'N-1' elements that are stored inline in the body
663 /// of the vector. The extra '1' element is stored in SmallVectorImpl.
664 typedef typename SmallVectorImpl<T>::U U;
666 // MinUs - The number of U's require to cover N T's.
667 MinUs = (static_cast<unsigned int>(sizeof(T))*N +
668 static_cast<unsigned int>(sizeof(U)) - 1) /
669 static_cast<unsigned int>(sizeof(U)),
671 // NumInlineEltsElts - The number of elements actually in this array. There
672 // is already one in the parent class, and we have to round up to avoid
673 // having a zero-element array.
674 NumInlineEltsElts = MinUs > 1 ? (MinUs - 1) : 1,
676 // NumTsAvailable - The number of T's we actually have space for, which may
677 // be more than N due to rounding.
678 NumTsAvailable = (NumInlineEltsElts+1)*static_cast<unsigned int>(sizeof(U))/
679 static_cast<unsigned int>(sizeof(T))
681 U InlineElts[NumInlineEltsElts];
683 SmallVector() : SmallVectorImpl<T>(NumTsAvailable) {
686 explicit SmallVector(unsigned Size, const T &Value = T())
687 : SmallVectorImpl<T>(NumTsAvailable) {
690 this->push_back(Value);
693 template<typename ItTy>
694 SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(NumTsAvailable) {
698 SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(NumTsAvailable) {
700 SmallVectorImpl<T>::operator=(RHS);
703 const SmallVector &operator=(const SmallVector &RHS) {
704 SmallVectorImpl<T>::operator=(RHS);
710 } // End llvm namespace
713 /// Implement std::swap in terms of SmallVector swap.
716 swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) {
720 /// Implement std::swap in terms of SmallVector swap.
721 template<typename T, unsigned N>
723 swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) {