1 //===--- ArrayRef.h - Array Reference Wrapper -------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_ADT_ARRAYREF_H
11 #define LLVM_ADT_ARRAYREF_H
13 #include "llvm/ADT/None.h"
14 #include "llvm/ADT/SmallVector.h"
19 /// ArrayRef - Represent a constant reference to an array (0 or more elements
20 /// consecutively in memory), i.e. a start pointer and a length. It allows
21 /// various APIs to take consecutive elements easily and conveniently.
23 /// This class does not own the underlying data, it is expected to be used in
24 /// situations where the data resides in some other buffer, whose lifetime
25 /// extends past that of the ArrayRef. For this reason, it is not in general
26 /// safe to store an ArrayRef.
28 /// This is intended to be trivially copyable, so it should be passed by
33 typedef const T *iterator;
34 typedef const T *const_iterator;
35 typedef size_t size_type;
37 typedef std::reverse_iterator<iterator> reverse_iterator;
40 /// The start of the array, in an external buffer.
43 /// The number of elements.
47 /// @name Constructors
50 /// Construct an empty ArrayRef.
51 /*implicit*/ ArrayRef() : Data(nullptr), Length(0) {}
53 /// Construct an empty ArrayRef from None.
54 /*implicit*/ ArrayRef(NoneType) : Data(nullptr), Length(0) {}
56 /// Construct an ArrayRef from a single element.
57 /*implicit*/ ArrayRef(const T &OneElt)
58 : Data(&OneElt), Length(1) {}
60 /// Construct an ArrayRef from a pointer and length.
61 /*implicit*/ ArrayRef(const T *data, size_t length)
62 : Data(data), Length(length) {}
64 /// Construct an ArrayRef from a range.
65 ArrayRef(const T *begin, const T *end)
66 : Data(begin), Length(end - begin) {}
68 /// Construct an ArrayRef from a SmallVector. This is templated in order to
69 /// avoid instantiating SmallVectorTemplateCommon<T> whenever we
70 /// copy-construct an ArrayRef.
72 /*implicit*/ ArrayRef(const SmallVectorTemplateCommon<T, U> &Vec)
73 : Data(Vec.data()), Length(Vec.size()) {
76 /// Construct an ArrayRef from a std::vector.
78 /*implicit*/ ArrayRef(const std::vector<T, A> &Vec)
79 : Data(Vec.data()), Length(Vec.size()) {}
81 /// Construct an ArrayRef from a C array.
83 /*implicit*/ LLVM_CONSTEXPR ArrayRef(const T (&Arr)[N])
84 : Data(Arr), Length(N) {}
86 #if LLVM_HAS_INITIALIZER_LISTS
87 /// Construct an ArrayRef from a std::initializer_list.
88 /*implicit*/ ArrayRef(const std::initializer_list<T> &Vec)
89 : Data(Vec.begin() == Vec.end() ? (T*)0 : Vec.begin()),
94 /// @name Simple Operations
97 iterator begin() const { return Data; }
98 iterator end() const { return Data + Length; }
100 reverse_iterator rbegin() const { return reverse_iterator(end()); }
101 reverse_iterator rend() const { return reverse_iterator(begin()); }
103 /// empty - Check if the array is empty.
104 bool empty() const { return Length == 0; }
106 const T *data() const { return Data; }
108 /// size - Get the array size.
109 size_t size() const { return Length; }
111 /// front - Get the first element.
112 const T &front() const {
117 /// back - Get the last element.
118 const T &back() const {
120 return Data[Length-1];
123 // copy - Allocate copy in Allocator and return ArrayRef<T> to it.
124 template <typename Allocator> ArrayRef<T> copy(Allocator &A) {
125 T *Buff = A.template Allocate<T>(Length);
126 std::copy(begin(), end(), Buff);
127 return ArrayRef<T>(Buff, Length);
130 /// equals - Check for element-wise equality.
131 bool equals(ArrayRef RHS) const {
132 if (Length != RHS.Length)
134 return std::equal(begin(), end(), RHS.begin());
137 /// slice(n) - Chop off the first N elements of the array.
138 ArrayRef<T> slice(unsigned N) const {
139 assert(N <= size() && "Invalid specifier");
140 return ArrayRef<T>(data()+N, size()-N);
143 /// slice(n, m) - Chop off the first N elements of the array, and keep M
144 /// elements in the array.
145 ArrayRef<T> slice(unsigned N, unsigned M) const {
146 assert(N+M <= size() && "Invalid specifier");
147 return ArrayRef<T>(data()+N, M);
150 // \brief Drop the last \p N elements of the array.
151 ArrayRef<T> drop_back(unsigned N = 1) const {
152 assert(size() >= N && "Dropping more elements than exist");
153 return slice(0, size() - N);
157 /// @name Operator Overloads
159 const T &operator[](size_t Index) const {
160 assert(Index < Length && "Invalid index!");
165 /// @name Expensive Operations
167 std::vector<T> vec() const {
168 return std::vector<T>(Data, Data+Length);
172 /// @name Conversion operators
174 operator std::vector<T>() const {
175 return std::vector<T>(Data, Data+Length);
181 /// MutableArrayRef - Represent a mutable reference to an array (0 or more
182 /// elements consecutively in memory), i.e. a start pointer and a length. It
183 /// allows various APIs to take and modify consecutive elements easily and
186 /// This class does not own the underlying data, it is expected to be used in
187 /// situations where the data resides in some other buffer, whose lifetime
188 /// extends past that of the MutableArrayRef. For this reason, it is not in
189 /// general safe to store a MutableArrayRef.
191 /// This is intended to be trivially copyable, so it should be passed by
194 class MutableArrayRef : public ArrayRef<T> {
198 typedef std::reverse_iterator<iterator> reverse_iterator;
200 /// Construct an empty MutableArrayRef.
201 /*implicit*/ MutableArrayRef() : ArrayRef<T>() {}
203 /// Construct an empty MutableArrayRef from None.
204 /*implicit*/ MutableArrayRef(NoneType) : ArrayRef<T>() {}
206 /// Construct an MutableArrayRef from a single element.
207 /*implicit*/ MutableArrayRef(T &OneElt) : ArrayRef<T>(OneElt) {}
209 /// Construct an MutableArrayRef from a pointer and length.
210 /*implicit*/ MutableArrayRef(T *data, size_t length)
211 : ArrayRef<T>(data, length) {}
213 /// Construct an MutableArrayRef from a range.
214 MutableArrayRef(T *begin, T *end) : ArrayRef<T>(begin, end) {}
216 /// Construct an MutableArrayRef from a SmallVector.
217 /*implicit*/ MutableArrayRef(SmallVectorImpl<T> &Vec)
218 : ArrayRef<T>(Vec) {}
220 /// Construct a MutableArrayRef from a std::vector.
221 /*implicit*/ MutableArrayRef(std::vector<T> &Vec)
222 : ArrayRef<T>(Vec) {}
224 /// Construct an MutableArrayRef from a C array.
226 /*implicit*/ LLVM_CONSTEXPR MutableArrayRef(T (&Arr)[N])
227 : ArrayRef<T>(Arr) {}
229 T *data() const { return const_cast<T*>(ArrayRef<T>::data()); }
231 iterator begin() const { return data(); }
232 iterator end() const { return data() + this->size(); }
234 reverse_iterator rbegin() const { return reverse_iterator(end()); }
235 reverse_iterator rend() const { return reverse_iterator(begin()); }
237 /// front - Get the first element.
239 assert(!this->empty());
243 /// back - Get the last element.
245 assert(!this->empty());
246 return data()[this->size()-1];
249 /// slice(n) - Chop off the first N elements of the array.
250 MutableArrayRef<T> slice(unsigned N) const {
251 assert(N <= this->size() && "Invalid specifier");
252 return MutableArrayRef<T>(data()+N, this->size()-N);
255 /// slice(n, m) - Chop off the first N elements of the array, and keep M
256 /// elements in the array.
257 MutableArrayRef<T> slice(unsigned N, unsigned M) const {
258 assert(N+M <= this->size() && "Invalid specifier");
259 return MutableArrayRef<T>(data()+N, M);
263 /// @name Operator Overloads
265 T &operator[](size_t Index) const {
266 assert(Index < this->size() && "Invalid index!");
267 return data()[Index];
271 /// @name ArrayRef Convenience constructors
274 /// Construct an ArrayRef from a single element.
276 ArrayRef<T> makeArrayRef(const T &OneElt) {
280 /// Construct an ArrayRef from a pointer and length.
282 ArrayRef<T> makeArrayRef(const T *data, size_t length) {
283 return ArrayRef<T>(data, length);
286 /// Construct an ArrayRef from a range.
288 ArrayRef<T> makeArrayRef(const T *begin, const T *end) {
289 return ArrayRef<T>(begin, end);
292 /// Construct an ArrayRef from a SmallVector.
293 template <typename T>
294 ArrayRef<T> makeArrayRef(const SmallVectorImpl<T> &Vec) {
298 /// Construct an ArrayRef from a SmallVector.
299 template <typename T, unsigned N>
300 ArrayRef<T> makeArrayRef(const SmallVector<T, N> &Vec) {
304 /// Construct an ArrayRef from a std::vector.
306 ArrayRef<T> makeArrayRef(const std::vector<T> &Vec) {
310 /// Construct an ArrayRef from a C array.
311 template<typename T, size_t N>
312 ArrayRef<T> makeArrayRef(const T (&Arr)[N]) {
313 return ArrayRef<T>(Arr);
317 /// @name ArrayRef Comparison Operators
321 inline bool operator==(ArrayRef<T> LHS, ArrayRef<T> RHS) {
322 return LHS.equals(RHS);
326 inline bool operator!=(ArrayRef<T> LHS, ArrayRef<T> RHS) {
327 return !(LHS == RHS);
332 // ArrayRefs can be treated like a POD type.
333 template <typename T> struct isPodLike;
334 template <typename T> struct isPodLike<ArrayRef<T> > {
335 static const bool value = true;