//===- 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_range.h"
#include "llvm/Support/AlignOf.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/type_traits.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <initializer_list>
#include <iterator>
#include <memory>
#include <new>
#include <type_traits>
#include <utility>
namespace llvm {
/// This is all the non-templated stuff common to all SmallVectors.
class SmallVectorBase {
protected:
void *BeginX, *EndX, *CapacityX;
protected:
SmallVectorBase(void *FirstEl, size_t Size)
: BeginX(FirstEl), EndX(FirstEl), CapacityX((char*)FirstEl+Size) {}
/// 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(void *FirstEl, size_t MinSizeInBytes, size_t TSize);
public:
/// 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);
}
LLVM_NODISCARD bool empty() const { return BeginX == EndX; }
};
/// This is the part of SmallVectorTemplateBase which does not depend on whether
/// the type T is a POD. The extra dummy template argument is used by ArrayRef
/// to avoid unnecessarily requiring T to be complete.
template <typename T, typename = void>
class SmallVectorTemplateCommon : public SmallVectorBase {
private:
template <typename, unsigned> friend struct SmallVectorStorage;
// 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. Use an array of char of sufficient alignment.
using U = AlignedCharArrayUnion<T>;
U FirstEl;
// Space after 'FirstEl' is clobbered, do not add any instance vars after it.
protected:
SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(&FirstEl, Size) {}
void grow_pod(size_t MinSizeInBytes, size_t TSize) {
SmallVectorBase::grow_pod(&FirstEl, MinSizeInBytes, TSize);
}
/// 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);
}
/// Put this vector in a state of being small.
void resetToSmall() {
BeginX = EndX = CapacityX = &FirstEl;
}
void setEnd(T *P) { this->EndX = P; }
public:
using size_type = size_t;
using difference_type = ptrdiff_t;
using value_type = T;
using iterator = T *;
using const_iterator = const T *;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using reverse_iterator = std::reverse_iterator<iterator>;
using reference = T &;
using const_reference = const T &;
using pointer = T *;
using const_pointer = const T *;
// forward iterator creation methods.
LLVM_ATTRIBUTE_ALWAYS_INLINE
iterator begin() { return (iterator)this->BeginX; }
LLVM_ATTRIBUTE_ALWAYS_INLINE
const_iterator begin() const { return (const_iterator)this->BeginX; }
LLVM_ATTRIBUTE_ALWAYS_INLINE
iterator end() { return (iterator)this->EndX; }
LLVM_ATTRIBUTE_ALWAYS_INLINE
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());}
LLVM_ATTRIBUTE_ALWAYS_INLINE
size_type size() const { return end()-begin(); }
size_type max_size() const { return size_type(-1) / sizeof(T); }
/// Return the total number of elements in the currently allocated buffer.
size_t capacity() const { return capacity_ptr() - begin(); }
/// Return a pointer to the vector's buffer, even if empty().
pointer data() { return pointer(begin()); }
/// Return a pointer to the vector's buffer, even if empty().
const_pointer data() const { return const_pointer(begin()); }
LLVM_ATTRIBUTE_ALWAYS_INLINE
reference operator[](size_type idx) {
assert(idx < size());
return begin()[idx];
}
LLVM_ATTRIBUTE_ALWAYS_INLINE
const_reference operator[](size_type idx) const {
assert(idx < size());
return begin()[idx];
}
reference front() {
assert(!empty());
return begin()[0];
}
const_reference front() const {
assert(!empty());
return begin()[0];
}
reference back() {
assert(!empty());
return end()[-1];
}
const_reference back() const {
assert(!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> {
protected:
SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {}
static void destroy_range(T *S, T *E) {
while (S != E) {
--E;
E->~T();
}
}
/// 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) {
std::uninitialized_copy(std::make_move_iterator(I),
std::make_move_iterator(E), Dest);
}
/// 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 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 (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
this->grow();
::new ((void*) this->end()) T(Elt);
this->setEnd(this->end()+1);
}
void push_back(T &&Elt) {
if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
this->grow();
::new ((void*) this->end()) T(::std::move(Elt));
this->setEnd(this->end()+1);
}
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();
// Always grow, even from zero.
size_t NewCapacity = size_t(NextPowerOf2(CurCapacity+2));
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 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);
}
/// 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);
}
/// 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,
typename std::enable_if<std::is_same<typename std::remove_const<T1>::type,
T2>::value>::type * = nullptr) {
// Use memcpy for PODs iterated by pointers (which includes SmallVector
// iterators): std::uninitialized_copy optimizes to memmove, but we can
// use memcpy here. Note that I and E are iterators and thus might be
// invalid for memcpy if they are equal.
if (I != E)
memcpy(Dest, I, (E - I) * sizeof(T));
}
/// 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 (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
this->grow();
memcpy(this->end(), &Elt, sizeof(T));
this->setEnd(this->end()+1);
}
void pop_back() {
this->setEnd(this->end()-1);
}
};
/// 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> {
using SuperClass = SmallVectorTemplateBase<T, isPodLike<T>::value>;
public:
using iterator = typename SuperClass::iterator;
using const_iterator = typename SuperClass::const_iterator;
using size_type = typename SuperClass::size_type;
protected:
// Default ctor - Initialize to empty.
explicit SmallVectorImpl(unsigned N)
: SmallVectorTemplateBase<T, isPodLike<T>::value>(N*sizeof(T)) {
}
public:
SmallVectorImpl(const SmallVectorImpl &) = delete;
~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(size_type 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);
for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
new (&*I) T();
this->setEnd(this->begin()+N);
}
}
void resize(size_type 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(size_type N) {
if (this->capacity() < N)
this->grow(N);
}
LLVM_NODISCARD T pop_back_val() {
T Result = ::std::move(this->back());
this->pop_back();
return Result;
}
void swap(SmallVectorImpl &RHS);
/// Add the specified range to the end of the SmallVector.
template <typename in_iter,
typename = typename std::enable_if<std::is_convertible<
typename std::iterator_traits<in_iter>::iterator_category,
std::input_iterator_tag>::value>::type>
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.
this->uninitialized_copy(in_start, in_end, this->end());
this->setEnd(this->end() + NumInputs);
}
/// 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 append(std::initializer_list<T> IL) {
append(IL.begin(), IL.end());
}
// FIXME: Consider assigning over existing elements, rather than clearing &
// re-initializing them - for all assign(...) variants.
void assign(size_type 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);
}
template <typename in_iter,
typename = typename std::enable_if<std::is_convertible<
typename std::iterator_traits<in_iter>::iterator_category,
std::input_iterator_tag>::value>::type>
void assign(in_iter in_start, in_iter in_end) {
clear();
append(in_start, in_end);
}
void assign(std::initializer_list<T> IL) {
clear();
append(IL);
}
iterator erase(const_iterator CI) {
// Just cast away constness because this is a non-const member function.
iterator I = const_cast<iterator>(CI);
assert(I >= this->begin() && "Iterator to erase is out of bounds.");
assert(I < this->end() && "Erasing at past-the-end iterator.");
iterator N = I;
// Shift all elts down one.
std::move(I+1, this->end(), I);
// Drop the last elt.
this->pop_back();
return(N);
}
iterator erase(const_iterator CS, const_iterator CE) {
// Just cast away constness because this is a non-const member function.
iterator S = const_cast<iterator>(CS);
iterator E = const_cast<iterator>(CE);
assert(S >= this->begin() && "Range to erase is out of bounds.");
assert(S <= E && "Trying to erase invalid range.");
assert(E <= this->end() && "Trying to erase past the end.");
iterator N = S;
// Shift all elts down.
iterator I = std::move(E, this->end(), S);
// Drop the last elts.
this->destroy_range(I, this->end());
this->setEnd(I);
return(N);
}
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;
}
assert(I >= this->begin() && "Insertion iterator is out of bounds.");
assert(I <= this->end() && "Inserting past the end of the vector.");
if (this->EndX >= this->CapacityX) {
size_t EltNo = I-this->begin();
this->grow();
I = this->begin()+EltNo;
}
::new ((void*) this->end()) T(::std::move(this->back()));
// Push everything else over.
std::move_backward(I, this->end()-1, this->end());
this->setEnd(this->end()+1);
// 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;
}
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;
}
assert(I >= this->begin() && "Insertion iterator is out of bounds.");
assert(I <= this->end() && "Inserting past the end of the vector.");
if (this->EndX >= this->CapacityX) {
size_t EltNo = I-this->begin();
this->grow();
I = this->begin()+EltNo;
}
::new ((void*) this->end()) T(std::move(this->back()));
// Push everything else over.
std::move_backward(I, this->end()-1, this->end());
this->setEnd(this->end()+1);
// 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;
}
iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
// Convert iterator to elt# to avoid invalidating iterator when we reserve()
size_t InsertElt = I - this->begin();
if (I == this->end()) { // Important special case for empty vector.
append(NumToInsert, Elt);
return this->begin()+InsertElt;
}
assert(I >= this->begin() && "Insertion iterator is out of bounds.");
assert(I <= this->end() && "Inserting past the end of the vector.");
// Ensure there is enough space.
reserve(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(std::move_iterator<iterator>(this->end() - NumToInsert),
std::move_iterator<iterator>(this->end()));
// Copy the existing elements that get replaced.
std::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.
// Move 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_move(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,
typename = typename std::enable_if<std::is_convertible<
typename std::iterator_traits<ItTy>::iterator_category,
std::input_iterator_tag>::value>::type>
iterator insert(iterator I, ItTy From, ItTy To) {
// Convert iterator to elt# to avoid invalidating iterator when we reserve()
size_t InsertElt = I - this->begin();
if (I == this->end()) { // Important special case for empty vector.
append(From, To);
return this->begin()+InsertElt;
}
assert(I >= this->begin() && "Insertion iterator is out of bounds.");
assert(I <= this->end() && "Inserting past the end of the vector.");
size_t NumToInsert = std::distance(From, To);
// Ensure there is enough space.
reserve(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(std::move_iterator<iterator>(this->end() - NumToInsert),
std::move_iterator<iterator>(this->end()));
// Copy the existing elements that get replaced.
std::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.
// Move 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_move(I, OldEnd, this->end()-NumOverwritten);
// Replace the overwritten part.
for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
*J = *From;
++J; ++From;
}
// Insert the non-overwritten middle part.
this->uninitialized_copy(From, To, OldEnd);
return I;
}
void insert(iterator I, std::initializer_list<T> IL) {
insert(I, IL.begin(), IL.end());
}
template <typename... ArgTypes> void emplace_back(ArgTypes &&... Args) {
if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
this->grow();
::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
this->setEnd(this->end() + 1);
}
SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
SmallVectorImpl &operator=(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 the array size to \p 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(size_type 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 (size_type i = 0; i != 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;
}
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 = std::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.
std::move(RHS.begin(), RHS.begin()+CurSize, 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;
}
/// Storage for the SmallVector elements which aren't contained in
/// SmallVectorTemplateCommon. There are 'N-1' elements here. The remaining '1'
/// element is in the base class. This is specialized for the N=1 and N=0 cases
/// to avoid allocating unnecessary storage.
template <typename T, unsigned N>
struct SmallVectorStorage {
typename SmallVectorTemplateCommon<T>::U InlineElts[N - 1];
};
template <typename T> struct SmallVectorStorage<T, 1> {};
template <typename T> struct SmallVectorStorage<T, 0> {};
/// 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> {
/// Inline space for elements which aren't stored in the base class.
SmallVectorStorage<T, N> Storage;
public:
SmallVector() : SmallVectorImpl<T>(N) {}
explicit SmallVector(size_t Size, const T &Value = T())
: SmallVectorImpl<T>(N) {
this->assign(Size, Value);
}
template <typename ItTy,
typename = typename std::enable_if<std::is_convertible<
typename std::iterator_traits<ItTy>::iterator_category,
std::input_iterator_tag>::value>::type>
SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
this->append(S, E);
}
template <typename RangeTy>
explicit SmallVector(const iterator_range<RangeTy> &R)
: SmallVectorImpl<T>(N) {
this->append(R.begin(), R.end());
}
SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) {
this->assign(IL);
}
SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
if (!RHS.empty())
SmallVectorImpl<T>::operator=(RHS);
}
const SmallVector &operator=(const SmallVector &RHS) {
SmallVectorImpl<T>::operator=(RHS);
return *this;
}
SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
if (!RHS.empty())
SmallVectorImpl<T>::operator=(::std::move(RHS));
}
SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
if (!RHS.empty())
SmallVectorImpl<T>::operator=(::std::move(RHS));
}
const SmallVector &operator=(SmallVector &&RHS) {
SmallVectorImpl<T>::operator=(::std::move(RHS));
return *this;
}
const SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
SmallVectorImpl<T>::operator=(::std::move(RHS));
return *this;
}
const SmallVector &operator=(std::initializer_list<T> IL) {
this->assign(IL);
return *this;
}
};
template<typename T, unsigned N>
static inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
return X.capacity_in_bytes();
}
} // end namespace llvm
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);
}
} // end namespace std
#endif // LLVM_ADT_SMALLVECTOR_H