//===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file defines the SmallVector class. // //===----------------------------------------------------------------------===// #ifndef LLVM_ADT_SMALLVECTOR_H #define LLVM_ADT_SMALLVECTOR_H #include "llvm/Support/type_traits.h" #include <algorithm> #include <cassert> #include <cstddef> #include <cstdlib> #include <cstring> #include <iterator> #include <memory> #ifdef _MSC_VER namespace std { #if _MSC_VER <= 1310 // Work around flawed VC++ implementation of std::uninitialized_copy. Define // additional overloads so that elements with pointer types are recognized as // scalars and not objects, causing bizarre type conversion errors. template<class T1, class T2> inline _Scalar_ptr_iterator_tag _Ptr_cat(T1 **, T2 **) { _Scalar_ptr_iterator_tag _Cat; return _Cat; } template<class T1, class T2> inline _Scalar_ptr_iterator_tag _Ptr_cat(T1* const *, T2 **) { _Scalar_ptr_iterator_tag _Cat; return _Cat; } #else // FIXME: It is not clear if the problem is fixed in VS 2005. What is clear // is that the above hack won't work if it wasn't fixed. #endif } #endif namespace llvm { /// SmallVectorBase - This is all the non-templated stuff common to all /// SmallVectors. class SmallVectorBase { protected: void *BeginX, *EndX, *CapacityX; // Allocate raw space for N elements of type T. If T has a ctor or dtor, we // don't want it to be automatically run, so we need to represent the space as // something else. An array of char would work great, but might not be // aligned sufficiently. Instead we use some number of union instances for // the space, which guarantee maximal alignment. union U { double D; long double LD; long long L; void *P; } FirstEl; // Space after 'FirstEl' is clobbered, do not add any instance vars after it. protected: SmallVectorBase(size_t Size) : BeginX(&FirstEl), EndX(&FirstEl), CapacityX((char*)&FirstEl+Size) {} /// isSmall - Return true if this is a smallvector which has not had dynamic /// memory allocated for it. bool isSmall() const { return BeginX == static_cast<const void*>(&FirstEl); } /// grow_pod - This is an implementation of the grow() method which only works /// on POD-like data types and is out of line to reduce code duplication. void grow_pod(size_t MinSizeInBytes, size_t TSize); public: /// size_in_bytes - This returns size()*sizeof(T). size_t size_in_bytes() const { return size_t((char*)EndX - (char*)BeginX); } /// capacity_in_bytes - This returns capacity()*sizeof(T). size_t capacity_in_bytes() const { return size_t((char*)CapacityX - (char*)BeginX); } bool empty() const { return BeginX == EndX; } }; template <typename T> class SmallVectorTemplateCommon : public SmallVectorBase { protected: void setEnd(T *P) { this->EndX = P; } public: SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(Size) {} typedef size_t size_type; typedef ptrdiff_t difference_type; typedef T value_type; typedef T *iterator; typedef const T *const_iterator; typedef std::reverse_iterator<const_iterator> const_reverse_iterator; typedef std::reverse_iterator<iterator> reverse_iterator; typedef T &reference; typedef const T &const_reference; typedef T *pointer; typedef const T *const_pointer; // forward iterator creation methods. iterator begin() { return (iterator)this->BeginX; } const_iterator begin() const { return (const_iterator)this->BeginX; } iterator end() { return (iterator)this->EndX; } const_iterator end() const { return (const_iterator)this->EndX; } protected: iterator capacity_ptr() { return (iterator)this->CapacityX; } const_iterator capacity_ptr() const { return (const_iterator)this->CapacityX;} public: // reverse iterator creation methods. reverse_iterator rbegin() { return reverse_iterator(end()); } const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); } reverse_iterator rend() { return reverse_iterator(begin()); } const_reverse_iterator rend() const { return const_reverse_iterator(begin());} size_type size() const { return end()-begin(); } size_type max_size() const { return size_type(-1) / sizeof(T); } /// capacity - Return the total number of elements in the currently allocated /// buffer. size_t capacity() const { return capacity_ptr() - begin(); } /// data - Return a pointer to the vector's buffer, even if empty(). pointer data() { return pointer(begin()); } /// data - Return a pointer to the vector's buffer, even if empty(). const_pointer data() const { return const_pointer(begin()); } reference operator[](unsigned idx) { assert(begin() + idx < end()); return begin()[idx]; } const_reference operator[](unsigned idx) const { assert(begin() + idx < end()); return begin()[idx]; } reference front() { return begin()[0]; } const_reference front() const { return begin()[0]; } reference back() { return end()[-1]; } const_reference back() const { return end()[-1]; } }; /// SmallVectorTemplateBase<isPodLike = false> - This is where we put method /// implementations that are designed to work with non-POD-like T's. template <typename T, bool isPodLike> class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> { public: SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} static void destroy_range(T *S, T *E) { while (S != E) { --E; E->~T(); } } /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory /// starting with "Dest", constructing elements into it as needed. template<typename It1, typename It2> static void uninitialized_copy(It1 I, It1 E, It2 Dest) { std::uninitialized_copy(I, E, Dest); } /// grow - double the size of the allocated memory, guaranteeing space for at /// least one more element or MinSize if specified. void grow(size_t MinSize = 0); }; // Define this out-of-line to dissuade the C++ compiler from inlining it. template <typename T, bool isPodLike> void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) { size_t CurCapacity = this->capacity(); size_t CurSize = this->size(); size_t NewCapacity = 2*CurCapacity + 1; // Always grow, even from zero. if (NewCapacity < MinSize) NewCapacity = MinSize; T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T))); // Copy the elements over. this->uninitialized_copy(this->begin(), this->end(), NewElts); // Destroy the original elements. destroy_range(this->begin(), this->end()); // If this wasn't grown from the inline copy, deallocate the old space. if (!this->isSmall()) free(this->begin()); this->setEnd(NewElts+CurSize); this->BeginX = NewElts; this->CapacityX = this->begin()+NewCapacity; } /// SmallVectorTemplateBase<isPodLike = true> - This is where we put method /// implementations that are designed to work with POD-like T's. template <typename T> class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> { public: SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} // No need to do a destroy loop for POD's. static void destroy_range(T *, T *) {} /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory /// starting with "Dest", constructing elements into it as needed. template<typename It1, typename It2> static void uninitialized_copy(It1 I, It1 E, It2 Dest) { // Arbitrary iterator types; just use the basic implementation. std::uninitialized_copy(I, E, Dest); } /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory /// starting with "Dest", constructing elements into it as needed. template<typename T1, typename T2> static void uninitialized_copy(T1 *I, T1 *E, T2 *Dest) { // Use memcpy for PODs iterated by pointers (which includes SmallVector // iterators): std::uninitialized_copy optimizes to memmove, but we can // use memcpy here. memcpy(Dest, I, (E-I)*sizeof(T)); } /// grow - double the size of the allocated memory, guaranteeing space for at /// least one more element or MinSize if specified. void grow(size_t MinSize = 0) { this->grow_pod(MinSize*sizeof(T), sizeof(T)); } }; /// SmallVectorImpl - This class consists of common code factored out of the /// SmallVector class to reduce code duplication based on the SmallVector 'N' /// template parameter. template <typename T> class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> { typedef SmallVectorTemplateBase<T, isPodLike<T>::value > SuperClass; SmallVectorImpl(const SmallVectorImpl&); // DISABLED. public: typedef typename SuperClass::iterator iterator; typedef typename SuperClass::size_type size_type; // Default ctor - Initialize to empty. explicit SmallVectorImpl(unsigned N) : SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) { } ~SmallVectorImpl() { // Destroy the constructed elements in the vector. this->destroy_range(this->begin(), this->end()); // If this wasn't grown from the inline copy, deallocate the old space. if (!this->isSmall()) free(this->begin()); } void clear() { this->destroy_range(this->begin(), this->end()); this->EndX = this->BeginX; } void resize(unsigned N) { if (N < this->size()) { this->destroy_range(this->begin()+N, this->end()); this->setEnd(this->begin()+N); } else if (N > this->size()) { if (this->capacity() < N) this->grow(N); this->construct_range(this->end(), this->begin()+N, T()); this->setEnd(this->begin()+N); } } void resize(unsigned N, const T &NV) { if (N < this->size()) { this->destroy_range(this->begin()+N, this->end()); this->setEnd(this->begin()+N); } else if (N > this->size()) { if (this->capacity() < N) this->grow(N); construct_range(this->end(), this->begin()+N, NV); this->setEnd(this->begin()+N); } } void reserve(unsigned N) { if (this->capacity() < N) this->grow(N); } void push_back(const T &Elt) { if (this->EndX < this->CapacityX) { Retry: new (this->end()) T(Elt); this->setEnd(this->end()+1); return; } this->grow(); goto Retry; } void pop_back() { this->setEnd(this->end()-1); this->end()->~T(); } T pop_back_val() { T Result = this->back(); pop_back(); return Result; } void swap(SmallVectorImpl &RHS); /// append - Add the specified range to the end of the SmallVector. /// template<typename in_iter> void append(in_iter in_start, in_iter in_end) { size_type NumInputs = std::distance(in_start, in_end); // Grow allocated space if needed. if (NumInputs > size_type(this->capacity_ptr()-this->end())) this->grow(this->size()+NumInputs); // Copy the new elements over. // TODO: NEED To compile time dispatch on whether in_iter is a random access // iterator to use the fast uninitialized_copy. std::uninitialized_copy(in_start, in_end, this->end()); this->setEnd(this->end() + NumInputs); } /// append - Add the specified range to the end of the SmallVector. /// void append(size_type NumInputs, const T &Elt) { // Grow allocated space if needed. if (NumInputs > size_type(this->capacity_ptr()-this->end())) this->grow(this->size()+NumInputs); // Copy the new elements over. std::uninitialized_fill_n(this->end(), NumInputs, Elt); this->setEnd(this->end() + NumInputs); } void assign(unsigned NumElts, const T &Elt) { clear(); if (this->capacity() < NumElts) this->grow(NumElts); this->setEnd(this->begin()+NumElts); construct_range(this->begin(), this->end(), Elt); } iterator erase(iterator I) { iterator N = I; // Shift all elts down one. std::copy(I+1, this->end(), I); // Drop the last elt. pop_back(); return(N); } iterator erase(iterator S, iterator E) { iterator N = S; // Shift all elts down. iterator I = std::copy(E, this->end(), S); // Drop the last elts. this->destroy_range(I, this->end()); this->setEnd(I); return(N); } iterator insert(iterator I, const T &Elt) { if (I == this->end()) { // Important special case for empty vector. push_back(Elt); return this->end()-1; } if (this->EndX < this->CapacityX) { Retry: new (this->end()) T(this->back()); this->setEnd(this->end()+1); // Push everything else over. std::copy_backward(I, this->end()-1, this->end()); // If we just moved the element we're inserting, be sure to update // the reference. const T *EltPtr = &Elt; if (I <= EltPtr && EltPtr < this->EndX) ++EltPtr; *I = *EltPtr; return I; } size_t EltNo = I-this->begin(); this->grow(); I = this->begin()+EltNo; goto Retry; } iterator insert(iterator I, size_type NumToInsert, const T &Elt) { if (I == this->end()) { // Important special case for empty vector. append(NumToInsert, Elt); return this->end()-1; } // Convert iterator to elt# to avoid invalidating iterator when we reserve() size_t InsertElt = I - this->begin(); // Ensure there is enough space. reserve(static_cast<unsigned>(this->size() + NumToInsert)); // Uninvalidate the iterator. I = this->begin()+InsertElt; // If there are more elements between the insertion point and the end of the // range than there are being inserted, we can use a simple approach to // insertion. Since we already reserved space, we know that this won't // reallocate the vector. if (size_t(this->end()-I) >= NumToInsert) { T *OldEnd = this->end(); append(this->end()-NumToInsert, this->end()); // Copy the existing elements that get replaced. std::copy_backward(I, OldEnd-NumToInsert, OldEnd); std::fill_n(I, NumToInsert, Elt); return I; } // Otherwise, we're inserting more elements than exist already, and we're // not inserting at the end. // Copy over the elements that we're about to overwrite. T *OldEnd = this->end(); this->setEnd(this->end() + NumToInsert); size_t NumOverwritten = OldEnd-I; this->uninitialized_copy(I, OldEnd, this->end()-NumOverwritten); // Replace the overwritten part. std::fill_n(I, NumOverwritten, Elt); // Insert the non-overwritten middle part. std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt); return I; } template<typename ItTy> iterator insert(iterator I, ItTy From, ItTy To) { if (I == this->end()) { // Important special case for empty vector. append(From, To); return this->end()-1; } size_t NumToInsert = std::distance(From, To); // Convert iterator to elt# to avoid invalidating iterator when we reserve() size_t InsertElt = I - this->begin(); // Ensure there is enough space. reserve(static_cast<unsigned>(this->size() + NumToInsert)); // Uninvalidate the iterator. I = this->begin()+InsertElt; // If there are more elements between the insertion point and the end of the // range than there are being inserted, we can use a simple approach to // insertion. Since we already reserved space, we know that this won't // reallocate the vector. if (size_t(this->end()-I) >= NumToInsert) { T *OldEnd = this->end(); append(this->end()-NumToInsert, this->end()); // Copy the existing elements that get replaced. std::copy_backward(I, OldEnd-NumToInsert, OldEnd); std::copy(From, To, I); return I; } // Otherwise, we're inserting more elements than exist already, and we're // not inserting at the end. // Copy over the elements that we're about to overwrite. T *OldEnd = this->end(); this->setEnd(this->end() + NumToInsert); size_t NumOverwritten = OldEnd-I; this->uninitialized_copy(I, OldEnd, this->end()-NumOverwritten); // Replace the overwritten part. for (; NumOverwritten > 0; --NumOverwritten) { *I = *From; ++I; ++From; } // Insert the non-overwritten middle part. this->uninitialized_copy(From, To, OldEnd); return I; } const SmallVectorImpl &operator=(const SmallVectorImpl &RHS); bool operator==(const SmallVectorImpl &RHS) const { if (this->size() != RHS.size()) return false; return std::equal(this->begin(), this->end(), RHS.begin()); } bool operator!=(const SmallVectorImpl &RHS) const { return !(*this == RHS); } bool operator<(const SmallVectorImpl &RHS) const { return std::lexicographical_compare(this->begin(), this->end(), RHS.begin(), RHS.end()); } /// set_size - Set the array size to \arg N, which the current array must have /// enough capacity for. /// /// This does not construct or destroy any elements in the vector. /// /// Clients can use this in conjunction with capacity() to write past the end /// of the buffer when they know that more elements are available, and only /// update the size later. This avoids the cost of value initializing elements /// which will only be overwritten. void set_size(unsigned N) { assert(N <= this->capacity()); this->setEnd(this->begin() + N); } private: static void construct_range(T *S, T *E, const T &Elt) { for (; S != E; ++S) new (S) T(Elt); } }; template <typename T> void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) { if (this == &RHS) return; // We can only avoid copying elements if neither vector is small. if (!this->isSmall() && !RHS.isSmall()) { std::swap(this->BeginX, RHS.BeginX); std::swap(this->EndX, RHS.EndX); std::swap(this->CapacityX, RHS.CapacityX); return; } if (RHS.size() > this->capacity()) this->grow(RHS.size()); if (this->size() > RHS.capacity()) RHS.grow(this->size()); // Swap the shared elements. size_t NumShared = this->size(); if (NumShared > RHS.size()) NumShared = RHS.size(); for (unsigned i = 0; i != static_cast<unsigned>(NumShared); ++i) std::swap((*this)[i], RHS[i]); // Copy over the extra elts. if (this->size() > RHS.size()) { size_t EltDiff = this->size() - RHS.size(); this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end()); RHS.setEnd(RHS.end()+EltDiff); this->destroy_range(this->begin()+NumShared, this->end()); this->setEnd(this->begin()+NumShared); } else if (RHS.size() > this->size()) { size_t EltDiff = RHS.size() - this->size(); this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end()); this->setEnd(this->end() + EltDiff); this->destroy_range(RHS.begin()+NumShared, RHS.end()); RHS.setEnd(RHS.begin()+NumShared); } } template <typename T> const SmallVectorImpl<T> &SmallVectorImpl<T>:: operator=(const SmallVectorImpl<T> &RHS) { // Avoid self-assignment. if (this == &RHS) return *this; // If we already have sufficient space, assign the common elements, then // destroy any excess. size_t RHSSize = RHS.size(); size_t CurSize = this->size(); if (CurSize >= RHSSize) { // Assign common elements. iterator NewEnd; if (RHSSize) NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin()); else NewEnd = this->begin(); // Destroy excess elements. this->destroy_range(NewEnd, this->end()); // Trim. this->setEnd(NewEnd); return *this; } // If we have to grow to have enough elements, destroy the current elements. // This allows us to avoid copying them during the grow. if (this->capacity() < RHSSize) { // Destroy current elements. this->destroy_range(this->begin(), this->end()); this->setEnd(this->begin()); CurSize = 0; this->grow(RHSSize); } else if (CurSize) { // Otherwise, use assignment for the already-constructed elements. std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin()); } // Copy construct the new elements in place. this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(), this->begin()+CurSize); // Set end. this->setEnd(this->begin()+RHSSize); return *this; } /// SmallVector - This is a 'vector' (really, a variable-sized array), optimized /// for the case when the array is small. It contains some number of elements /// in-place, which allows it to avoid heap allocation when the actual number of /// elements is below that threshold. This allows normal "small" cases to be /// fast without losing generality for large inputs. /// /// Note that this does not attempt to be exception safe. /// template <typename T, unsigned N> class SmallVector : public SmallVectorImpl<T> { /// InlineElts - These are 'N-1' elements that are stored inline in the body /// of the vector. The extra '1' element is stored in SmallVectorImpl. typedef typename SmallVectorImpl<T>::U U; enum { // MinUs - The number of U's require to cover N T's. MinUs = (static_cast<unsigned int>(sizeof(T))*N + static_cast<unsigned int>(sizeof(U)) - 1) / static_cast<unsigned int>(sizeof(U)), // NumInlineEltsElts - The number of elements actually in this array. There // is already one in the parent class, and we have to round up to avoid // having a zero-element array. NumInlineEltsElts = MinUs > 1 ? (MinUs - 1) : 1, // NumTsAvailable - The number of T's we actually have space for, which may // be more than N due to rounding. NumTsAvailable = (NumInlineEltsElts+1)*static_cast<unsigned int>(sizeof(U))/ static_cast<unsigned int>(sizeof(T)) }; U InlineElts[NumInlineEltsElts]; public: SmallVector() : SmallVectorImpl<T>(NumTsAvailable) { } explicit SmallVector(unsigned Size, const T &Value = T()) : SmallVectorImpl<T>(NumTsAvailable) { this->reserve(Size); while (Size--) this->push_back(Value); } template<typename ItTy> SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(NumTsAvailable) { this->append(S, E); } SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(NumTsAvailable) { if (!RHS.empty()) SmallVectorImpl<T>::operator=(RHS); } const SmallVector &operator=(const SmallVector &RHS) { SmallVectorImpl<T>::operator=(RHS); return *this; } }; /// Specialize SmallVector at N=0. This specialization guarantees /// that it can be instantiated at an incomplete T if none of its /// members are required. template <typename T> class SmallVector<T,0> : public SmallVectorImpl<T> { public: SmallVector() : SmallVectorImpl<T>(0) {} explicit SmallVector(unsigned Size, const T &Value = T()) : SmallVectorImpl<T>(0) { this->reserve(Size); while (Size--) this->push_back(Value); } template<typename ItTy> SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(0) { this->append(S, E); } SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(0) { SmallVectorImpl<T>::operator=(RHS); } SmallVector &operator=(const SmallVectorImpl<T> &RHS) { return SmallVectorImpl<T>::operator=(RHS); } }; template<typename T, unsigned N> static inline size_t capacity_in_bytes(const SmallVector<T, N> &X) { return X.capacity_in_bytes(); } } // End llvm namespace namespace std { /// Implement std::swap in terms of SmallVector swap. template<typename T> inline void swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) { LHS.swap(RHS); } /// Implement std::swap in terms of SmallVector swap. template<typename T, unsigned N> inline void swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) { LHS.swap(RHS); } } #endif