llvm-6502/include/llvm/ADT/SmallVector.h
John McCall 38dbb60675 Update SmallVector to support move semantics if the host does.
Note that support for rvalue references does not imply support
for the full set of move-related STL operations.

I've preserved support for an odd little thing in insert() where
we're trying to support inserting a new element from an existing
one.  If we actually want to support that, there's a lot more we
need to do:  insert can call either grow or push_back, neither of
which is safe against this particular use pattern.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155979 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-02 05:39:15 +00:00

947 lines
29 KiB
C++

//===- 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/Compiler.h"
#include "llvm/Support/type_traits.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <iterator>
#include <memory>
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);
}
/// resetToSmall - Put this vector in a state of being small.
void resetToSmall() {
BeginX = EndX = CapacityX = &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:
SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(Size) {}
void setEnd(T *P) { this->EndX = P; }
public:
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> {
protected:
SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
static void destroy_range(T *S, T *E) {
while (S != E) {
--E;
E->~T();
}
}
/// move - Use move-assignment to move the range [I, E) onto the
/// objects starting with "Dest". This is just <memory>'s
/// std::move, but not all stdlibs actually provide that.
template<typename It1, typename It2>
static It2 move(It1 I, It1 E, It2 Dest) {
#if LLVM_USE_RVALUE_REFERENCES
for (; I != E; ++I, ++Dest)
*Dest = ::std::move(*I);
return Dest;
#else
return ::std::copy(I, E, Dest);
#endif
}
/// move_backward - Use move-assignment to move the range
/// [I, E) onto the objects ending at "Dest", moving objects
/// in reverse order. This is just <algorithm>'s
/// std::move_backward, but not all stdlibs actually provide that.
template<typename It1, typename It2>
static It2 move_backward(It1 I, It1 E, It2 Dest) {
#if LLVM_USE_RVALUE_REFERENCES
while (I != E)
*--Dest = ::std::move(*--E);
return Dest;
#else
return ::std::copy_backward(I, E, Dest);
#endif
}
/// uninitialized_move - Move the range [I, E) into the uninitialized
/// memory starting with "Dest", constructing elements as needed.
template<typename It1, typename It2>
static void uninitialized_move(It1 I, It1 E, It2 Dest) {
#if LLVM_USE_RVALUE_REFERENCES
for (; I != E; ++I, ++Dest)
::new ((void*) &*Dest) T(::std::move(*I));
#else
::std::uninitialized_copy(I, E, Dest);
#endif
}
/// uninitialized_copy - Copy the range [I, E) onto the uninitialized
/// memory starting with "Dest", constructing elements as needed.
template<typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
std::uninitialized_copy(I, E, Dest);
}
/// grow - Grow the allocated memory (without initializing new
/// elements), doubling the size of the allocated memory.
/// Guarantees space for at least one more element, or MinSize more
/// elements if specified.
void grow(size_t MinSize = 0);
public:
void push_back(const T &Elt) {
if (this->EndX < this->CapacityX) {
Retry:
::new ((void*) this->end()) T(Elt);
this->setEnd(this->end()+1);
return;
}
this->grow();
goto Retry;
}
#if LLVM_USE_RVALUE_REFERENCES
void push_back(T &&Elt) {
if (this->EndX < this->CapacityX) {
Retry:
::new ((void*) this->end()) T(::std::move(Elt));
this->setEnd(this->end()+1);
return;
}
this->grow();
goto Retry;
}
#endif
void pop_back() {
this->setEnd(this->end()-1);
this->end()->~T();
}
};
// 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)));
// Move the elements over.
this->uninitialized_move(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> {
protected:
SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
// No need to do a destroy loop for POD's.
static void destroy_range(T *, T *) {}
/// move - Use move-assignment to move the range [I, E) onto the
/// objects starting with "Dest". For PODs, this is just memcpy.
template<typename It1, typename It2>
static It2 move(It1 I, It1 E, It2 Dest) {
return ::std::copy(I, E, Dest);
}
/// move_backward - Use move-assignment to move the range
/// [I, E) onto the objects ending at "Dest", moving objects
/// in reverse order.
template<typename It1, typename It2>
static It2 move_backward(It1 I, It1 E, It2 Dest) {
return ::std::copy_backward(I, E, Dest);
}
/// uninitialized_move - Move 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_move(It1 I, It1 E, It2 Dest) {
// Just do a copy.
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 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));
}
public:
void push_back(const T &Elt) {
if (this->EndX < this->CapacityX) {
Retry:
memcpy(this->end(), &Elt, sizeof(T));
this->setEnd(this->end()+1);
return;
}
this->grow();
goto Retry;
}
void pop_back() {
this->setEnd(this->end()-1);
}
};
/// 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;
protected:
// Default ctor - Initialize to empty.
explicit SmallVectorImpl(unsigned N)
: SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) {
}
public:
~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);
std::uninitialized_fill(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);
std::uninitialized_fill(this->end(), this->begin()+N, NV);
this->setEnd(this->begin()+N);
}
}
void reserve(unsigned N) {
if (this->capacity() < N)
this->grow(N);
}
T pop_back_val() {
#if LLVM_USE_RVALUE_REFERENCES
T Result = ::std::move(this->back());
#else
T Result = this->back();
#endif
this->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);
std::uninitialized_fill(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.
this->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);
}
#if LLVM_USE_RVALUE_REFERENCES
iterator insert(iterator I, T &&Elt) {
if (I == this->end()) { // Important special case for empty vector.
this->push_back(::std::move(Elt));
return this->end()-1;
}
if (this->EndX < this->CapacityX) {
Retry:
::new ((void*) this->end()) T(::std::move(this->back()));
this->setEnd(this->end()+1);
// Push everything else over.
this->move_backward(I, this->end()-1, this->end());
// If we just moved the element we're inserting, be sure to update
// the reference.
T *EltPtr = &Elt;
if (I <= EltPtr && EltPtr < this->EndX)
++EltPtr;
*I = ::std::move(*EltPtr);
return I;
}
size_t EltNo = I-this->begin();
this->grow();
I = this->begin()+EltNo;
goto Retry;
}
#endif
iterator insert(iterator I, const T &Elt) {
if (I == this->end()) { // Important special case for empty vector.
this->push_back(Elt);
return this->end()-1;
}
if (this->EndX < this->CapacityX) {
Retry:
::new ((void*) this->end()) T(this->back());
this->setEnd(this->end()+1);
// Push everything else over.
this->move_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.
this->move_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.
this->move_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;
}
SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
#if LLVM_USE_RVALUE_REFERENCES
SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
#endif
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);
}
};
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>
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.
// FIXME: don't do this if they're efficiently moveable.
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;
}
#if LLVM_USE_RVALUE_REFERENCES
template <typename T>
SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
// Avoid self-assignment.
if (this == &RHS) return *this;
// If the RHS isn't small, clear this vector and then steal its buffer.
if (!RHS.isSmall()) {
this->destroy_range(this->begin(), this->end());
if (!this->isSmall()) free(this->begin());
this->BeginX = RHS.BeginX;
this->EndX = RHS.EndX;
this->CapacityX = RHS.CapacityX;
RHS.resetToSmall();
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 = this->begin();
if (RHSSize)
NewEnd = this->move(RHS.begin(), RHS.end(), NewEnd);
// Destroy excess elements and trim the bounds.
this->destroy_range(NewEnd, this->end());
this->setEnd(NewEnd);
// Clear the RHS.
RHS.clear();
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.
// FIXME: this may not actually make any sense if we can efficiently move
// elements.
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.
this->move(RHS.begin(), RHS.end(), this->begin());
}
// Move-construct the new elements in place.
this->uninitialized_move(RHS.begin()+CurSize, RHS.end(),
this->begin()+CurSize);
// Set end.
this->setEnd(this->begin()+RHSSize);
RHS.clear();
return *this;
}
#endif
/// 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->assign(Size, 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;
}
#if LLVM_USE_RVALUE_REFERENCES
SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(NumTsAvailable) {
if (!RHS.empty())
SmallVectorImpl<T>::operator=(::std::move(RHS));
}
const SmallVector &operator=(SmallVector &&RHS) {
SmallVectorImpl<T>::operator=(::std::move(RHS));
return *this;
}
#endif
};
/// 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->assign(Size, 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