//===- ArrayRef.h - Array Reference Wrapper ---------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_ARRAYREF_H
#define LLVM_ADT_ARRAYREF_H
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Compiler.h"
#include <algorithm>
#include <array>
#include <cassert>
#include <cstddef>
#include <initializer_list>
#include <iterator>
#include <memory>
#include <type_traits>
#include <vector>
namespace llvm {
/// ArrayRef - Represent a constant reference to an array (0 or more elements
/// consecutively in memory), i.e. a start pointer and a length. It allows
/// various APIs to take consecutive elements easily and conveniently.
///
/// This class does not own the underlying data, it is expected to be used in
/// situations where the data resides in some other buffer, whose lifetime
/// extends past that of the ArrayRef. For this reason, it is not in general
/// safe to store an ArrayRef.
///
/// This is intended to be trivially copyable, so it should be passed by
/// value.
template<typename T>
class LLVM_NODISCARD ArrayRef {
public:
using iterator = const T *;
using const_iterator = const T *;
using size_type = size_t;
using reverse_iterator = std::reverse_iterator<iterator>;
private:
/// The start of the array, in an external buffer.
const T *Data = nullptr;
/// The number of elements.
size_type Length = 0;
public:
/// @name Constructors
/// @{
/// Construct an empty ArrayRef.
/*implicit*/ ArrayRef() = default;
/// Construct an empty ArrayRef from None.
/*implicit*/ ArrayRef(NoneType) {}
/// Construct an ArrayRef from a single element.
/*implicit*/ ArrayRef(const T &OneElt)
: Data(&OneElt), Length(1) {}
/// Construct an ArrayRef from a pointer and length.
/*implicit*/ ArrayRef(const T *data, size_t length)
: Data(data), Length(length) {}
/// Construct an ArrayRef from a range.
ArrayRef(const T *begin, const T *end)
: Data(begin), Length(end - begin) {}
/// Construct an ArrayRef from a SmallVector. This is templated in order to
/// avoid instantiating SmallVectorTemplateCommon<T> whenever we
/// copy-construct an ArrayRef.
template<typename U>
/*implicit*/ ArrayRef(const SmallVectorTemplateCommon<T, U> &Vec)
: Data(Vec.data()), Length(Vec.size()) {
}
/// Construct an ArrayRef from a std::vector.
template<typename A>
/*implicit*/ ArrayRef(const std::vector<T, A> &Vec)
: Data(Vec.data()), Length(Vec.size()) {}
/// Construct an ArrayRef from a std::array
template <size_t N>
/*implicit*/ constexpr ArrayRef(const std::array<T, N> &Arr)
: Data(Arr.data()), Length(N) {}
/// Construct an ArrayRef from a C array.
template <size_t N>
/*implicit*/ constexpr ArrayRef(const T (&Arr)[N]) : Data(Arr), Length(N) {}
/// Construct an ArrayRef from a std::initializer_list.
/*implicit*/ ArrayRef(const std::initializer_list<T> &Vec)
: Data(Vec.begin() == Vec.end() ? (T*)nullptr : Vec.begin()),
Length(Vec.size()) {}
/// Construct an ArrayRef<const T*> from ArrayRef<T*>. This uses SFINAE to
/// ensure that only ArrayRefs of pointers can be converted.
template <typename U>
ArrayRef(
const ArrayRef<U *> &A,
typename std::enable_if<
std::is_convertible<U *const *, T const *>::value>::type * = nullptr)
: Data(A.data()), Length(A.size()) {}
/// Construct an ArrayRef<const T*> from a SmallVector<T*>. This is
/// templated in order to avoid instantiating SmallVectorTemplateCommon<T>
/// whenever we copy-construct an ArrayRef.
template<typename U, typename DummyT>
/*implicit*/ ArrayRef(
const SmallVectorTemplateCommon<U *, DummyT> &Vec,
typename std::enable_if<
std::is_convertible<U *const *, T const *>::value>::type * = nullptr)
: Data(Vec.data()), Length(Vec.size()) {
}
/// Construct an ArrayRef<const T*> from std::vector<T*>. This uses SFINAE
/// to ensure that only vectors of pointers can be converted.
template<typename U, typename A>
ArrayRef(const std::vector<U *, A> &Vec,
typename std::enable_if<
std::is_convertible<U *const *, T const *>::value>::type* = 0)
: Data(Vec.data()), Length(Vec.size()) {}
/// @}
/// @name Simple Operations
/// @{
iterator begin() const { return Data; }
iterator end() const { return Data + Length; }
reverse_iterator rbegin() const { return reverse_iterator(end()); }
reverse_iterator rend() const { return reverse_iterator(begin()); }
/// empty - Check if the array is empty.
bool empty() const { return Length == 0; }
const T *data() const { return Data; }
/// size - Get the array size.
size_t size() const { return Length; }
/// front - Get the first element.
const T &front() const {
assert(!empty());
return Data[0];
}
/// back - Get the last element.
const T &back() const {
assert(!empty());
return Data[Length-1];
}
// copy - Allocate copy in Allocator and return ArrayRef<T> to it.
template <typename Allocator> ArrayRef<T> copy(Allocator &A) {
T *Buff = A.template Allocate<T>(Length);
std::uninitialized_copy(begin(), end(), Buff);
return ArrayRef<T>(Buff, Length);
}
/// equals - Check for element-wise equality.
bool equals(ArrayRef RHS) const {
if (Length != RHS.Length)
return false;
return std::equal(begin(), end(), RHS.begin());
}
/// slice(n, m) - Chop off the first N elements of the array, and keep M
/// elements in the array.
ArrayRef<T> slice(size_t N, size_t M) const {
assert(N+M <= size() && "Invalid specifier");
return ArrayRef<T>(data()+N, M);
}
/// slice(n) - Chop off the first N elements of the array.
ArrayRef<T> slice(size_t N) const { return slice(N, size() - N); }
/// Drop the first \p N elements of the array.
ArrayRef<T> drop_front(size_t N = 1) const {
assert(size() >= N && "Dropping more elements than exist");
return slice(N, size() - N);
}
/// Drop the last \p N elements of the array.
ArrayRef<T> drop_back(size_t N = 1) const {
assert(size() >= N && "Dropping more elements than exist");
return slice(0, size() - N);
}
/// Return a copy of *this with the first N elements satisfying the
/// given predicate removed.
template <class PredicateT> ArrayRef<T> drop_while(PredicateT Pred) const {
return ArrayRef<T>(find_if_not(*this, Pred), end());
}
/// Return a copy of *this with the first N elements not satisfying
/// the given predicate removed.
template <class PredicateT> ArrayRef<T> drop_until(PredicateT Pred) const {
return ArrayRef<T>(find_if(*this, Pred), end());
}
/// Return a copy of *this with only the first \p N elements.
ArrayRef<T> take_front(size_t N = 1) const {
if (N >= size())
return *this;
return drop_back(size() - N);
}
/// Return a copy of *this with only the last \p N elements.
ArrayRef<T> take_back(size_t N = 1) const {
if (N >= size())
return *this;
return drop_front(size() - N);
}
/// Return the first N elements of this Array that satisfy the given
/// predicate.
template <class PredicateT> ArrayRef<T> take_while(PredicateT Pred) const {
return ArrayRef<T>(begin(), find_if_not(*this, Pred));
}
/// Return the first N elements of this Array that don't satisfy the
/// given predicate.
template <class PredicateT> ArrayRef<T> take_until(PredicateT Pred) const {
return ArrayRef<T>(begin(), find_if(*this, Pred));
}
/// @}
/// @name Operator Overloads
/// @{
const T &operator[](size_t Index) const {
assert(Index < Length && "Invalid index!");
return Data[Index];
}
/// Disallow accidental assignment from a temporary.
///
/// The declaration here is extra complicated so that "arrayRef = {}"
/// continues to select the move assignment operator.
template <typename U>
typename std::enable_if<std::is_same<U, T>::value, ArrayRef<T>>::type &
operator=(U &&Temporary) = delete;
/// Disallow accidental assignment from a temporary.
///
/// The declaration here is extra complicated so that "arrayRef = {}"
/// continues to select the move assignment operator.
template <typename U>
typename std::enable_if<std::is_same<U, T>::value, ArrayRef<T>>::type &
operator=(std::initializer_list<U>) = delete;
/// @}
/// @name Expensive Operations
/// @{
std::vector<T> vec() const {
return std::vector<T>(Data, Data+Length);
}
/// @}
/// @name Conversion operators
/// @{
operator std::vector<T>() const {
return std::vector<T>(Data, Data+Length);
}
/// @}
};
/// MutableArrayRef - Represent a mutable reference to an array (0 or more
/// elements consecutively in memory), i.e. a start pointer and a length. It
/// allows various APIs to take and modify consecutive elements easily and
/// conveniently.
///
/// This class does not own the underlying data, it is expected to be used in
/// situations where the data resides in some other buffer, whose lifetime
/// extends past that of the MutableArrayRef. For this reason, it is not in
/// general safe to store a MutableArrayRef.
///
/// This is intended to be trivially copyable, so it should be passed by
/// value.
template<typename T>
class LLVM_NODISCARD MutableArrayRef : public ArrayRef<T> {
public:
using iterator = T *;
using reverse_iterator = std::reverse_iterator<iterator>;
/// Construct an empty MutableArrayRef.
/*implicit*/ MutableArrayRef() = default;
/// Construct an empty MutableArrayRef from None.
/*implicit*/ MutableArrayRef(NoneType) : ArrayRef<T>() {}
/// Construct an MutableArrayRef from a single element.
/*implicit*/ MutableArrayRef(T &OneElt) : ArrayRef<T>(OneElt) {}
/// Construct an MutableArrayRef from a pointer and length.
/*implicit*/ MutableArrayRef(T *data, size_t length)
: ArrayRef<T>(data, length) {}
/// Construct an MutableArrayRef from a range.
MutableArrayRef(T *begin, T *end) : ArrayRef<T>(begin, end) {}
/// Construct an MutableArrayRef from a SmallVector.
/*implicit*/ MutableArrayRef(SmallVectorImpl<T> &Vec)
: ArrayRef<T>(Vec) {}
/// Construct a MutableArrayRef from a std::vector.
/*implicit*/ MutableArrayRef(std::vector<T> &Vec)
: ArrayRef<T>(Vec) {}
/// Construct an ArrayRef from a std::array
template <size_t N>
/*implicit*/ constexpr MutableArrayRef(std::array<T, N> &Arr)
: ArrayRef<T>(Arr) {}
/// Construct an MutableArrayRef from a C array.
template <size_t N>
/*implicit*/ constexpr MutableArrayRef(T (&Arr)[N]) : ArrayRef<T>(Arr) {}
T *data() const { return const_cast<T*>(ArrayRef<T>::data()); }
iterator begin() const { return data(); }
iterator end() const { return data() + this->size(); }
reverse_iterator rbegin() const { return reverse_iterator(end()); }
reverse_iterator rend() const { return reverse_iterator(begin()); }
/// front - Get the first element.
T &front() const {
assert(!this->empty());
return data()[0];
}
/// back - Get the last element.
T &back() const {
assert(!this->empty());
return data()[this->size()-1];
}
/// slice(n, m) - Chop off the first N elements of the array, and keep M
/// elements in the array.
MutableArrayRef<T> slice(size_t N, size_t M) const {
assert(N + M <= this->size() && "Invalid specifier");
return MutableArrayRef<T>(this->data() + N, M);
}
/// slice(n) - Chop off the first N elements of the array.
MutableArrayRef<T> slice(size_t N) const {
return slice(N, this->size() - N);
}
/// Drop the first \p N elements of the array.
MutableArrayRef<T> drop_front(size_t N = 1) const {
assert(this->size() >= N && "Dropping more elements than exist");
return slice(N, this->size() - N);
}
MutableArrayRef<T> drop_back(size_t N = 1) const {
assert(this->size() >= N && "Dropping more elements than exist");
return slice(0, this->size() - N);
}
/// Return a copy of *this with the first N elements satisfying the
/// given predicate removed.
template <class PredicateT>
MutableArrayRef<T> drop_while(PredicateT Pred) const {
return MutableArrayRef<T>(find_if_not(*this, Pred), end());
}
/// Return a copy of *this with the first N elements not satisfying
/// the given predicate removed.
template <class PredicateT>
MutableArrayRef<T> drop_until(PredicateT Pred) const {
return MutableArrayRef<T>(find_if(*this, Pred), end());
}
/// Return a copy of *this with only the first \p N elements.
MutableArrayRef<T> take_front(size_t N = 1) const {
if (N >= this->size())
return *this;
return drop_back(this->size() - N);
}
/// Return a copy of *this with only the last \p N elements.
MutableArrayRef<T> take_back(size_t N = 1) const {
if (N >= this->size())
return *this;
return drop_front(this->size() - N);
}
/// Return the first N elements of this Array that satisfy the given
/// predicate.
template <class PredicateT>
MutableArrayRef<T> take_while(PredicateT Pred) const {
return MutableArrayRef<T>(begin(), find_if_not(*this, Pred));
}
/// Return the first N elements of this Array that don't satisfy the
/// given predicate.
template <class PredicateT>
MutableArrayRef<T> take_until(PredicateT Pred) const {
return MutableArrayRef<T>(begin(), find_if(*this, Pred));
}
/// @}
/// @name Operator Overloads
/// @{
T &operator[](size_t Index) const {
assert(Index < this->size() && "Invalid index!");
return data()[Index];
}
};
/// This is a MutableArrayRef that owns its array.
template <typename T> class OwningArrayRef : public MutableArrayRef<T> {
public:
OwningArrayRef() = default;
OwningArrayRef(size_t Size) : MutableArrayRef<T>(new T[Size], Size) {}
OwningArrayRef(ArrayRef<T> Data)
: MutableArrayRef<T>(new T[Data.size()], Data.size()) {
std::copy(Data.begin(), Data.end(), this->begin());
}
OwningArrayRef(OwningArrayRef &&Other) { *this = Other; }
OwningArrayRef &operator=(OwningArrayRef &&Other) {
delete[] this->data();
this->MutableArrayRef<T>::operator=(Other);
Other.MutableArrayRef<T>::operator=(MutableArrayRef<T>());
return *this;
}
~OwningArrayRef() { delete[] this->data(); }
};
/// @name ArrayRef Convenience constructors
/// @{
/// Construct an ArrayRef from a single element.
template<typename T>
ArrayRef<T> makeArrayRef(const T &OneElt) {
return OneElt;
}
/// Construct an ArrayRef from a pointer and length.
template<typename T>
ArrayRef<T> makeArrayRef(const T *data, size_t length) {
return ArrayRef<T>(data, length);
}
/// Construct an ArrayRef from a range.
template<typename T>
ArrayRef<T> makeArrayRef(const T *begin, const T *end) {
return ArrayRef<T>(begin, end);
}
/// Construct an ArrayRef from a SmallVector.
template <typename T>
ArrayRef<T> makeArrayRef(const SmallVectorImpl<T> &Vec) {
return Vec;
}
/// Construct an ArrayRef from a SmallVector.
template <typename T, unsigned N>
ArrayRef<T> makeArrayRef(const SmallVector<T, N> &Vec) {
return Vec;
}
/// Construct an ArrayRef from a std::vector.
template<typename T>
ArrayRef<T> makeArrayRef(const std::vector<T> &Vec) {
return Vec;
}
/// Construct an ArrayRef from an ArrayRef (no-op) (const)
template <typename T> ArrayRef<T> makeArrayRef(const ArrayRef<T> &Vec) {
return Vec;
}
/// Construct an ArrayRef from an ArrayRef (no-op)
template <typename T> ArrayRef<T> &makeArrayRef(ArrayRef<T> &Vec) {
return Vec;
}
/// Construct an ArrayRef from a C array.
template<typename T, size_t N>
ArrayRef<T> makeArrayRef(const T (&Arr)[N]) {
return ArrayRef<T>(Arr);
}
/// Construct a MutableArrayRef from a single element.
template<typename T>
MutableArrayRef<T> makeMutableArrayRef(T &OneElt) {
return OneElt;
}
/// Construct a MutableArrayRef from a pointer and length.
template<typename T>
MutableArrayRef<T> makeMutableArrayRef(T *data, size_t length) {
return MutableArrayRef<T>(data, length);
}
/// @}
/// @name ArrayRef Comparison Operators
/// @{
template<typename T>
inline bool operator==(ArrayRef<T> LHS, ArrayRef<T> RHS) {
return LHS.equals(RHS);
}
template<typename T>
inline bool operator!=(ArrayRef<T> LHS, ArrayRef<T> RHS) {
return !(LHS == RHS);
}
/// @}
// ArrayRefs can be treated like a POD type.
template <typename T> struct isPodLike;
template <typename T> struct isPodLike<ArrayRef<T>> {
static const bool value = true;
};
template <typename T> hash_code hash_value(ArrayRef<T> S) {
return hash_combine_range(S.begin(), S.end());
}
} // end namespace llvm
#endif // LLVM_ADT_ARRAYREF_H