//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Chris Lattner and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#ifndef LLVM_ADT_SMALLVECTOR_H
#define LLVM_ADT_SMALLVECTOR_H
+#include "llvm/Support/type_traits.h"
#include <algorithm>
#include <cassert>
-#include <iterator>
+#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 {
-/// 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 {
+/// 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 either use GCC extensions, or some
// number of union instances for the space, which guarantee maximal alignment.
+#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.
- /// InlineElts - These are the 'N' elements that are stored inline in the body
- /// of the vector
- U InlineElts[(sizeof(T)*N+sizeof(U)-1)/sizeof(U)];
- T *Begin, *End, *Capacity;
-public:
- // Default ctor - Initialize to empty.
- SmallVector() : Begin((T*)InlineElts), End(Begin), Capacity(Begin+N) {
+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);
}
- SmallVector(const SmallVector &RHS) {
- unsigned RHSSize = RHS.size();
- Begin = (T*)InlineElts;
-
- // Doesn't fit in the small case? Allocate space.
- if (RHSSize > N) {
- End = Capacity = Begin;
- grow(RHSSize);
- }
- End = Begin+RHSSize;
- Capacity = Begin+N;
- std::uninitialized_copy(RHS.begin(), RHS.end(), Begin);
+ /// size_in_bytes - This returns size()*sizeof(T).
+ size_t size_in_bytes() const {
+ return size_t((char*)EndX - (char*)BeginX);
}
- ~SmallVector() {
- // Destroy the constructed elements in the vector.
- for (iterator I = Begin, E = End; I != E; ++I)
- I->~T();
-
- // If this wasn't grown from the inline copy, deallocate the old space.
- if ((void*)Begin != (void*)InlineElts)
- delete[] (char*)Begin;
+
+ /// capacity_in_bytes - This returns capacity()*sizeof(T).
+ size_t capacity_in_bytes() const {
+ return size_t((char*)CapacityX - (char*)BeginX);
}
- typedef size_t size_type;
- typedef T* iterator;
- typedef const T* const_iterator;
- typedef T& reference;
- typedef const T& const_reference;
+ /// grow_pod - This is an implementation of the grow() method which only works
+ /// on POD-like datatypes and is out of line to reduce code duplication.
+ void grow_pod(size_t MinSizeInBytes, size_t TSize);
+
+public:
+ bool empty() const { return BeginX == EndX; }
+};
+
- bool empty() const { return Begin == End; }
- size_type size() const { return End-Begin; }
+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;
- iterator begin() { return Begin; }
- const_iterator begin() const { return Begin; }
+ 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());}
- iterator end() { return End; }
- const_iterator end() const { return End; }
+ 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(idx < size() && "out of range reference!");
- return Begin[idx];
+ assert(begin() + idx < end());
+ return begin()[idx];
}
const_reference operator[](unsigned idx) const {
- assert(idx < size() && "out of range reference!");
- return Begin[idx];
+ assert(begin() + idx < end());
+ return begin()[idx];
}
-
+
+ reference front() {
+ return begin()[0];
+ }
+ const_reference front() const {
+ return begin()[0];
+ }
+
reference back() {
- assert(!empty() && "SmallVector is empty!");
return end()[-1];
}
const_reference back() const {
- assert(!empty() && "SmallVector is empty!");
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;
+ if (NewCapacity < MinSize)
+ NewCapacity = MinSize;
+ T *NewElts = static_cast<T*>(operator new(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())
+ operator delete(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) {
+ // Use memcpy for PODs: std::uninitialized_copy optimizes to memmove, memcpy
+ // is better.
+ 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;
+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())
+ operator delete(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_reference Elt) {
- if (End < Capacity) {
- Retry:
- new (End) T(Elt);
- ++End;
+ void push_back(const T &Elt) {
+ if (this->EndX < this->CapacityX) {
+ Retry:
+ new (this->end()) T(Elt);
+ this->setEnd(this->end()+1);
return;
}
- grow();
+ this->grow();
goto Retry;
}
void pop_back() {
- assert(!empty() && "SmallVector is empty!");
- --End;
- End->~T();
+ 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) {
- unsigned NumInputs = std::distance(in_start, in_end);
+ size_type NumInputs = std::distance(in_start, in_end);
// Grow allocated space if needed.
- if (End+NumInputs > Capacity)
- grow(size()+NumInputs);
-
+ if (NumInputs > size_type(this->capacity_ptr()-this->end()))
+ this->grow(this->size()+NumInputs);
+
// Copy the new elements over.
- std::uninitialized_copy(in_start, in_end, End);
- End += NumInputs;
+ // 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);
}
- const SmallVector &operator=(const SmallVector &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 = RHS.size();
- unsigned CurSize = size();
- if (CurSize >= RHSSize) {
- // Assign common elements.
- std::copy(RHS.Begin, RHS.Begin+RHSSize, Begin);
+ /// 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());
+ *I = Elt;
+ 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());
- // Destroy excess elements.
- for (unsigned i = RHSSize; i != CurSize; ++i)
- Begin[i].~T();
+ // Copy the existing elements that get replaced.
+ std::copy_backward(I, OldEnd-NumToInsert, OldEnd);
- // Trim.
- End = Begin + RHSSize;
- return *this;
+ std::fill_n(I, NumToInsert, Elt);
+ return I;
}
- // If we have to grow to have enough elements, destroy the current elements.
- // This allows us to avoid copying them during the grow.
- if (Capacity-Begin < RHSSize) {
- // Destroy current elements.
- for (iterator I = Begin, E = End; I != E; ++I)
- I->~T();
- 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);
+ // 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;
}
- // Copy construct the new elements in place.
- std::uninitialized_copy(RHS.Begin+CurSize, RHS.End, Begin+CurSize);
+ 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);
- // Set end.
- End = Begin+RHSSize;
+ // Replace the overwritten part.
+ std::copy(From, From+NumOverwritten, I);
+
+ // Insert the non-overwritten middle part.
+ this->uninitialized_copy(From+NumOverwritten, 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:
- /// isSmall - Return true if this is a smallvector which has not had dynamic
- /// memory allocated for it.
- bool isSmall() const {
- return (void*)Begin == (void*)InlineElts;
+ static void construct_range(T *S, T *E, const T &Elt) {
+ for (; S != E; ++S)
+ new (S) T(Elt);
}
+};
+
- /// grow - double the size of the allocated memory, guaranteeing space for at
- /// least one more element or MinSize if specified.
- void grow(unsigned MinSize = 0) {
- unsigned CurCapacity = Capacity-Begin;
- unsigned CurSize = size();
- unsigned NewCapacity = 2*CurCapacity;
- if (NewCapacity < MinSize)
- NewCapacity = MinSize;
- T *NewElts = reinterpret_cast<T*>(new char[NewCapacity*sizeof(T)]);
+template <typename T>
+void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
+ if (this == &RHS) return;
- // Copy the elements over.
- std::uninitialized_copy(Begin, End, NewElts);
-
- // Destroy the original elements.
- for (iterator I = Begin, E = End; I != E; ++I)
- I->~T();
-
- // If this wasn't grown from the inline copy, deallocate the old space.
- if (!isSmall())
- delete[] (char*)Begin;
-
- Begin = NewElts;
- End = NewElts+CurSize;
- Capacity = Begin+NewCapacity;
+ // 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;
+ }
+
};
} // 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