#define LLVM_ADT_SMALLVECTOR_H
#include <algorithm>
-#include <cassert>
#include <iterator>
#include <memory>
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 {
+/// 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;
- };
-
- /// 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;
+ } FirstEl;
+#endif
+ // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
public:
// Default ctor - Initialize to empty.
- SmallVector() : Begin((T*)InlineElts), End(Begin), Capacity(Begin+N) {
+ SmallVectorImpl(unsigned N)
+ : Begin((T*)&FirstEl), End((T*)&FirstEl), Capacity((T*)&FirstEl+N) {
}
- 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);
- }
- ~SmallVector() {
+ ~SmallVectorImpl() {
// Destroy the constructed elements in the vector.
- for (iterator I = Begin, E = End; I != E; ++I)
- I->~T();
+ destroy_range(Begin, End);
// If this wasn't grown from the inline copy, deallocate the old space.
- if ((void*)Begin != (void*)InlineElts)
+ if (!isSmall())
delete[] (char*)Begin;
}
const_iterator end() const { return End; }
reference operator[](unsigned idx) {
- assert(idx < size() && "out of range reference!");
return Begin[idx];
}
const_reference operator[](unsigned idx) const {
- assert(idx < size() && "out of range reference!");
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];
}
}
void pop_back() {
- assert(!empty() && "SmallVector is empty!");
--End;
End->~T();
}
+ 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 (Begin+N > Capacity)
+ 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 (Begin+N > Capacity)
+ 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>
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);
-
- // Destroy excess elements.
- for (unsigned i = RHSSize; i != CurSize; ++i)
- Begin[i].~T();
-
- // Trim.
- End = Begin + RHSSize;
- return *this;
+ void assign(unsigned NumElts, const T &Elt) {
+ clear();
+ if (Begin+NumElts > Capacity)
+ grow(NumElts);
+ End = Begin+NumElts;
+ construct_range(Begin, End, Elt);
+ }
+
+ void erase(iterator I) {
+ // Shift all elts down one.
+ std::copy(I+1, End, I);
+ // Drop the last elt.
+ pop_back();
+ }
+
+ void erase(iterator S, iterator E) {
+ // Shift all elts down.
+ iterator I = std::copy(E, End, S);
+ // Drop the last elts.
+ destroy_range(I, End);
+ End = I;
+ }
+
+ iterator insert(iterator I, const T &Elt) {
+ if (I == End) { // Important special case for empty vector.
+ push_back(Elt);
+ return end()-1;
}
- // 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);
+ if (End < Capacity) {
+ Retry:
+ new (End) T(back());
+ ++End;
+ // Push everything else over.
+ std::copy_backward(I, End-1, End);
+ *I = Elt;
+ return I;
}
-
- // Copy construct the new elements in place.
- std::uninitialized_copy(RHS.Begin+CurSize, RHS.End, Begin+CurSize);
-
- // Set end.
- End = Begin+RHSSize;
+ unsigned EltNo = I-Begin;
+ grow();
+ I = Begin+EltNo;
+ goto Retry;
}
+ const SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
+
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;
+ return (void*)Begin == (void*)&FirstEl;
}
/// 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)]);
-
- // Copy the elements over.
- std::uninitialized_copy(Begin, End, NewElts);
+ void grow(unsigned 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->~T();
+ --E;
+ }
+ }
+};
+
+// Define this out-of-line to dissuade the C++ compiler from inlining it.
+template <typename T>
+void SmallVectorImpl<T>::grow(unsigned MinSize) {
+ 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)]);
+
+ // Copy the elements over.
+ std::uninitialized_copy(Begin, End, NewElts);
+
+ // Destroy the original elements.
+ destroy_range(Begin, End);
+
+ // 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;
+}
+
+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 (Begin+RHS.size() > Capacity)
+ grow(RHS.size());
+ if (RHS.begin()+size() > RHS.Capacity)
+ RHS.grow(size());
+
+ // Swap the shared elements.
+ unsigned NumShared = size();
+ if (NumShared > RHS.size()) NumShared = RHS.size();
+ for (unsigned i = 0; i != NumShared; ++i)
+ std::swap(Begin[i], RHS[i]);
+
+ // Copy over the extra elts.
+ if (size() > RHS.size()) {
+ unsigned 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()) {
+ unsigned 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 = RHS.size();
+ unsigned CurSize = size();
+ if (CurSize >= RHSSize) {
+ // Assign common elements.
+ iterator NewEnd = std::copy(RHS.Begin, RHS.Begin+RHSSize, Begin);
- // Destroy the original elements.
- for (iterator I = Begin, E = End; I != E; ++I)
- I->~T();
+ // Destroy excess elements.
+ destroy_range(NewEnd, End);
- // If this wasn't grown from the inline copy, deallocate the old space.
- if (!isSmall())
- delete[] (char*)Begin;
+ // 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 = (sizeof(T)*N+sizeof(U)-1)/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) > 0 ? (MinUs - 1) : 1,
- Begin = NewElts;
- End = NewElts+CurSize;
- Capacity = Begin+NewCapacity*2;
+ // NumTsAvailable - The number of T's we actually have space for, which may
+ // be more than N due to rounding.
+ NumTsAvailable = (NumInlineEltsElts+1)*sizeof(U) / sizeof(T)
+ };
+ U InlineElts[NumInlineEltsElts];
+public:
+ SmallVector() : SmallVectorImpl<T>(NumTsAvailable) {
+ }
+
+ template<typename ItTy>
+ SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(NumTsAvailable) {
+ append(S, E);
+ }
+
+ SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(NumTsAvailable) {
+ 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
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