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Diffstat (limited to 'include/llvm/ADT/SmallVector.h')
| -rw-r--r-- | include/llvm/ADT/SmallVector.h | 617 |
1 files changed, 617 insertions, 0 deletions
diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h new file mode 100644 index 000000000000..f59a438d3eb4 --- /dev/null +++ b/include/llvm/ADT/SmallVector.h @@ -0,0 +1,617 @@ +//===- 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/ADT/iterator.h" +#include "llvm/Support/type_traits.h" +#include <algorithm> +#include <cassert> +#include <cstring> +#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 { + +/// 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 { +protected: + T *Begin, *End, *Capacity; + + // 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 either use GCC extensions, or some + // number of union instances for the space, which guarantee maximal alignment. +protected: +#ifdef __GNUC__ + typedef char U; + U FirstEl __attribute__((aligned)); +#else + union U { + double D; + long double LD; + long long L; + void *P; + } FirstEl; +#endif + // Space after 'FirstEl' is clobbered, do not add any instance vars after it. +public: + // Default ctor - Initialize to empty. + explicit SmallVectorImpl(unsigned N) + : Begin(reinterpret_cast<T*>(&FirstEl)), + End(reinterpret_cast<T*>(&FirstEl)), + Capacity(reinterpret_cast<T*>(&FirstEl)+N) { + } + + ~SmallVectorImpl() { + // Destroy the constructed elements in the vector. + destroy_range(Begin, End); + + // If this wasn't grown from the inline copy, deallocate the old space. + if (!isSmall()) + operator delete(Begin); + } + + 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; + + bool empty() const { return Begin == End; } + size_type size() const { return End-Begin; } + size_type max_size() const { return size_type(-1) / sizeof(T); } + + // forward iterator creation methods. + iterator begin() { return Begin; } + const_iterator begin() const { return Begin; } + iterator end() { return End; } + const_iterator end() const { return End; } + + // 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());} + + + 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]; + } + + void push_back(const_reference Elt) { + if (End < Capacity) { + Retry: + new (End) T(Elt); + ++End; + return; + } + grow(); + goto Retry; + } + + void pop_back() { + --End; + End->~T(); + } + + T pop_back_val() { + T Result = back(); + pop_back(); + return Result; + } + + void clear() { + destroy_range(Begin, End); + End = Begin; + } + + void resize(unsigned N) { + if (N < size()) { + destroy_range(Begin+N, End); + End = Begin+N; + } else if (N > size()) { + if (unsigned(Capacity-Begin) < N) + grow(N); + construct_range(End, Begin+N, T()); + End = Begin+N; + } + } + + void resize(unsigned N, const T &NV) { + if (N < size()) { + destroy_range(Begin+N, End); + End = Begin+N; + } else if (N > size()) { + if (unsigned(Capacity-Begin) < N) + grow(N); + construct_range(End, Begin+N, NV); + End = Begin+N; + } + } + + void reserve(unsigned N) { + if (unsigned(Capacity-Begin) < N) + grow(N); + } + + 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(Capacity-End)) + grow(size()+NumInputs); + + // Copy the new elements over. + std::uninitialized_copy(in_start, in_end, End); + 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(Capacity-End)) + grow(size()+NumInputs); + + // Copy the new elements over. + std::uninitialized_fill_n(End, NumInputs, Elt); + End += NumInputs; + } + + void assign(unsigned NumElts, const T &Elt) { + clear(); + if (unsigned(Capacity-Begin) < NumElts) + grow(NumElts); + End = Begin+NumElts; + construct_range(Begin, End, Elt); + } + + iterator erase(iterator I) { + iterator N = I; + // Shift all elts down one. + std::copy(I+1, 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, End, S); + // Drop the last elts. + destroy_range(I, End); + End = I; + return(N); + } + + iterator insert(iterator I, const T &Elt) { + if (I == End) { // Important special case for empty vector. + push_back(Elt); + return end()-1; + } + + if (End < Capacity) { + Retry: + new (End) T(back()); + ++End; + // Push everything else over. + std::copy_backward(I, End-1, End); + *I = Elt; + return I; + } + size_t EltNo = I-Begin; + grow(); + I = Begin+EltNo; + goto Retry; + } + + iterator insert(iterator I, size_type NumToInsert, const T &Elt) { + if (I == End) { // Important special case for empty vector. + append(NumToInsert, Elt); + return end()-1; + } + + // Convert iterator to elt# to avoid invalidating iterator when we reserve() + size_t InsertElt = I-begin(); + + // Ensure there is enough space. + reserve(static_cast<unsigned>(size() + NumToInsert)); + + // Uninvalidate the iterator. + I = 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(end()-I) >= NumToInsert) { + T *OldEnd = End; + append(End-NumToInsert, 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 = End; + End += NumToInsert; + size_t NumOverwritten = OldEnd-I; + std::uninitialized_copy(I, OldEnd, 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 == End) { // Important special case for empty vector. + append(From, To); + return end()-1; + } + + size_t NumToInsert = std::distance(From, To); + // Convert iterator to elt# to avoid invalidating iterator when we reserve() + size_t InsertElt = I-begin(); + + // Ensure there is enough space. + reserve(static_cast<unsigned>(size() + NumToInsert)); + + // Uninvalidate the iterator. + I = 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(end()-I) >= NumToInsert) { + T *OldEnd = End; + append(End-NumToInsert, 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 = End; + End += NumToInsert; + size_t NumOverwritten = OldEnd-I; + std::uninitialized_copy(I, OldEnd, End-NumOverwritten); + + // Replace the overwritten part. + std::copy(From, From+NumOverwritten, I); + + // Insert the non-overwritten middle part. + std::uninitialized_copy(From+NumOverwritten, To, OldEnd); + return I; + } + + /// 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); + } + + const SmallVectorImpl &operator=(const SmallVectorImpl &RHS); + + bool operator==(const SmallVectorImpl &RHS) const { + if (size() != RHS.size()) return false; + for (T *This = Begin, *That = RHS.Begin, *E = Begin+size(); + This != E; ++This, ++That) + if (*This != *That) + return false; + return true; + } + bool operator!=(const SmallVectorImpl &RHS) const { return !(*this == RHS); } + + bool operator<(const SmallVectorImpl &RHS) const { + return std::lexicographical_compare(begin(), end(), + RHS.begin(), RHS.end()); + } + +private: + /// isSmall - Return true if this is a smallvector which has not had dynamic + /// memory allocated for it. + bool isSmall() const { + return static_cast<const void*>(Begin) == + static_cast<const void*>(&FirstEl); + } + + /// grow - double the size of the allocated memory, guaranteeing space for at + /// least one more element or MinSize if specified. + void grow(size_type MinSize = 0); + + void construct_range(T *S, T *E, const T &Elt) { + for (; S != E; ++S) + new (S) T(Elt); + } + + void destroy_range(T *S, T *E) { + while (S != E) { + --E; + E->~T(); + } + } +}; + +// Define this out-of-line to dissuade the C++ compiler from inlining it. +template <typename T> +void SmallVectorImpl<T>::grow(size_t MinSize) { + size_t CurCapacity = Capacity-Begin; + size_t CurSize = size(); + size_t NewCapacity = 2*CurCapacity; + if (NewCapacity < MinSize) + NewCapacity = MinSize; + T *NewElts = static_cast<T*>(operator new(NewCapacity*sizeof(T))); + + // Copy the elements over. + if (is_class<T>::value) + std::uninitialized_copy(Begin, End, NewElts); + else + // Use memcpy for PODs (std::uninitialized_copy optimizes to memmove). + memcpy(NewElts, Begin, CurSize * sizeof(T)); + + // Destroy the original elements. + destroy_range(Begin, End); + + // If this wasn't grown from the inline copy, deallocate the old space. + if (!isSmall()) + operator delete(Begin); + + Begin = NewElts; + End = NewElts+CurSize; + Capacity = Begin+NewCapacity; +} + +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 (!isSmall() && !RHS.isSmall()) { + std::swap(Begin, RHS.Begin); + std::swap(End, RHS.End); + std::swap(Capacity, RHS.Capacity); + return; + } + if (RHS.size() > size_type(Capacity-Begin)) + grow(RHS.size()); + if (size() > size_type(RHS.Capacity-RHS.begin())) + RHS.grow(size()); + + // Swap the shared elements. + size_t NumShared = size(); + if (NumShared > RHS.size()) NumShared = RHS.size(); + for (unsigned i = 0; i != static_cast<unsigned>(NumShared); ++i) + std::swap(Begin[i], RHS[i]); + + // Copy over the extra elts. + if (size() > RHS.size()) { + size_t EltDiff = size() - RHS.size(); + std::uninitialized_copy(Begin+NumShared, End, RHS.End); + RHS.End += EltDiff; + destroy_range(Begin+NumShared, End); + End = Begin+NumShared; + } else if (RHS.size() > size()) { + size_t EltDiff = RHS.size() - size(); + std::uninitialized_copy(RHS.Begin+NumShared, RHS.End, End); + End += EltDiff; + destroy_range(RHS.Begin+NumShared, RHS.End); + RHS.End = 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. + unsigned RHSSize = unsigned(RHS.size()); + unsigned CurSize = unsigned(size()); + if (CurSize >= RHSSize) { + // Assign common elements. + iterator NewEnd; + if (RHSSize) + NewEnd = std::copy(RHS.Begin, RHS.Begin+RHSSize, Begin); + else + NewEnd = Begin; + + // Destroy excess elements. + destroy_range(NewEnd, End); + + // Trim. + End = 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 (unsigned(Capacity-Begin) < RHSSize) { + // Destroy current elements. + destroy_range(Begin, End); + End = Begin; + CurSize = 0; + grow(RHSSize); + } else if (CurSize) { + // Otherwise, use assignment for the already-constructed elements. + std::copy(RHS.Begin, RHS.Begin+CurSize, Begin); + } + + // Copy construct the new elements in place. + std::uninitialized_copy(RHS.Begin+CurSize, RHS.End, Begin+CurSize); + + // Set end. + End = 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; + } + +}; + +} // 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 |