1//===--- ArrayRef.h - Array Reference Wrapper -------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9 10#ifndef LLVM_ADT_ARRAYREF_H 11#define LLVM_ADT_ARRAYREF_H 12 13#include "llvm/ADT/SmallVector.h" 14#include <vector> 15 16namespace llvm { 17 18 /// ArrayRef - Represent a constant reference to an array (0 or more elements 19 /// consecutively in memory), i.e. a start pointer and a length. It allows 20 /// various APIs to take consecutive elements easily and conveniently. 21 /// 22 /// This class does not own the underlying data, it is expected to be used in 23 /// situations where the data resides in some other buffer, whose lifetime 24 /// extends past that of the ArrayRef. For this reason, it is not in general 25 /// safe to store an ArrayRef. 26 /// 27 /// This is intended to be trivially copyable, so it should be passed by 28 /// value. 29 template<typename T> 30 class ArrayRef { 31 public: 32 typedef const T *iterator; 33 typedef const T *const_iterator; 34 typedef size_t size_type; 35 36 private: 37 /// The start of the array, in an external buffer. 38 const T *Data; 39 40 /// The number of elements. 41 size_type Length; 42 43 public: 44 /// @name Constructors 45 /// @{ 46 47 /// Construct an empty ArrayRef. 48 /*implicit*/ ArrayRef() : Data(0), Length(0) {} 49 50 /// Construct an ArrayRef from a single element. 51 /*implicit*/ ArrayRef(const T &OneElt) 52 : Data(&OneElt), Length(1) {} 53 54 /// Construct an ArrayRef from a pointer and length. 55 /*implicit*/ ArrayRef(const T *data, size_t length) 56 : Data(data), Length(length) {} 57 58 /// Construct an ArrayRef from a range. 59 ArrayRef(const T *begin, const T *end) 60 : Data(begin), Length(end - begin) {} 61 62 /// Construct an ArrayRef from a SmallVector. 63 /*implicit*/ ArrayRef(const SmallVectorImpl<T> &Vec) 64 : Data(Vec.data()), Length(Vec.size()) {} 65 66 /// Construct an ArrayRef from a std::vector. 67 /*implicit*/ ArrayRef(const std::vector<T> &Vec) 68 : Data(Vec.empty() ? (T*)0 : &Vec[0]), Length(Vec.size()) {} 69 70 /// Construct an ArrayRef from a C array. 71 template <size_t N> 72 /*implicit*/ ArrayRef(const T (&Arr)[N]) 73 : Data(Arr), Length(N) {} 74 75 /// @} 76 /// @name Simple Operations 77 /// @{ 78 79 iterator begin() const { return Data; } 80 iterator end() const { return Data + Length; } 81 82 /// empty - Check if the array is empty. 83 bool empty() const { return Length == 0; } 84 85 const T *data() const { return Data; } 86 87 /// size - Get the array size. 88 size_t size() const { return Length; } 89 90 /// front - Get the first element. 91 const T &front() const { 92 assert(!empty()); 93 return Data[0]; 94 } 95 96 /// back - Get the last element. 97 const T &back() const { 98 assert(!empty()); 99 return Data[Length-1]; 100 } 101 102 /// equals - Check for element-wise equality. 103 bool equals(ArrayRef RHS) const { 104 if (Length != RHS.Length) 105 return false; 106 for (size_type i = 0; i != Length; i++) 107 if (Data[i] != RHS.Data[i]) 108 return false; 109 return true; 110 } 111 112 /// slice(n) - Chop off the first N elements of the array. 113 ArrayRef<T> slice(unsigned N) const { 114 assert(N <= size() && "Invalid specifier"); 115 return ArrayRef<T>(data()+N, size()-N); 116 } 117 118 /// slice(n, m) - Chop off the first N elements of the array, and keep M 119 /// elements in the array. 120 ArrayRef<T> slice(unsigned N, unsigned M) const { 121 assert(N+M <= size() && "Invalid specifier"); 122 return ArrayRef<T>(data()+N, M); 123 } 124 125 /// @} 126 /// @name Operator Overloads 127 /// @{ 128 const T &operator[](size_t Index) const { 129 assert(Index < Length && "Invalid index!"); 130 return Data[Index]; 131 } 132 133 /// @} 134 /// @name Expensive Operations 135 /// @{ 136 std::vector<T> vec() const { 137 return std::vector<T>(Data, Data+Length); 138 } 139 140 /// @} 141 /// @name Conversion operators 142 /// @{ 143 operator std::vector<T>() const { 144 return std::vector<T>(Data, Data+Length); 145 } 146 147 /// @} 148 }; 149 150 /// MutableArrayRef - Represent a mutable reference to an array (0 or more 151 /// elements consecutively in memory), i.e. a start pointer and a length. It 152 /// allows various APIs to take and modify consecutive elements easily and 153 /// conveniently. 154 /// 155 /// This class does not own the underlying data, it is expected to be used in 156 /// situations where the data resides in some other buffer, whose lifetime 157 /// extends past that of the MutableArrayRef. For this reason, it is not in 158 /// general safe to store a MutableArrayRef. 159 /// 160 /// This is intended to be trivially copyable, so it should be passed by 161 /// value. 162 template<typename T> 163 class MutableArrayRef : public ArrayRef<T> { 164 public: 165 typedef T *iterator; 166 167 /// Construct an empty ArrayRef. 168 /*implicit*/ MutableArrayRef() : ArrayRef<T>() {} 169 170 /// Construct an MutableArrayRef from a single element. 171 /*implicit*/ MutableArrayRef(T &OneElt) : ArrayRef<T>(OneElt) {} 172 173 /// Construct an MutableArrayRef from a pointer and length. 174 /*implicit*/ MutableArrayRef(T *data, size_t length) 175 : ArrayRef<T>(data, length) {} 176 177 /// Construct an MutableArrayRef from a range. 178 MutableArrayRef(T *begin, T *end) : ArrayRef<T>(begin, end) {} 179 180 /// Construct an MutableArrayRef from a SmallVector. 181 /*implicit*/ MutableArrayRef(SmallVectorImpl<T> &Vec) 182 : ArrayRef<T>(Vec) {} 183 184 /// Construct a MutableArrayRef from a std::vector. 185 /*implicit*/ MutableArrayRef(std::vector<T> &Vec) 186 : ArrayRef<T>(Vec) {} 187 188 /// Construct an MutableArrayRef from a C array. 189 template <size_t N> 190 /*implicit*/ MutableArrayRef(T (&Arr)[N]) 191 : ArrayRef<T>(Arr) {} 192 193 T *data() const { return const_cast<T*>(ArrayRef<T>::data()); } 194 195 iterator begin() const { return data(); } 196 iterator end() const { return data() + this->size(); } 197 198 /// front - Get the first element. 199 T &front() const { 200 assert(!this->empty()); 201 return data()[0]; 202 } 203 204 /// back - Get the last element. 205 T &back() const { 206 assert(!this->empty()); 207 return data()[this->size()-1]; 208 } 209 210 /// slice(n) - Chop off the first N elements of the array. 211 MutableArrayRef<T> slice(unsigned N) const { 212 assert(N <= this->size() && "Invalid specifier"); 213 return MutableArrayRef<T>(data()+N, this->size()-N); 214 } 215 216 /// slice(n, m) - Chop off the first N elements of the array, and keep M 217 /// elements in the array. 218 MutableArrayRef<T> slice(unsigned N, unsigned M) const { 219 assert(N+M <= this->size() && "Invalid specifier"); 220 return MutableArrayRef<T>(data()+N, M); 221 } 222 223 /// @} 224 /// @name Operator Overloads 225 /// @{ 226 T &operator[](size_t Index) const { 227 assert(Index < this->size() && "Invalid index!"); 228 return data()[Index]; 229 } 230 }; 231 232 /// @name ArrayRef Convenience constructors 233 /// @{ 234 235 /// Construct an ArrayRef from a single element. 236 template<typename T> 237 ArrayRef<T> makeArrayRef(const T &OneElt) { 238 return OneElt; 239 } 240 241 /// Construct an ArrayRef from a pointer and length. 242 template<typename T> 243 ArrayRef<T> makeArrayRef(const T *data, size_t length) { 244 return ArrayRef<T>(data, length); 245 } 246 247 /// Construct an ArrayRef from a range. 248 template<typename T> 249 ArrayRef<T> makeArrayRef(const T *begin, const T *end) { 250 return ArrayRef<T>(begin, end); 251 } 252 253 /// Construct an ArrayRef from a SmallVector. 254 template <typename T> 255 ArrayRef<T> makeArrayRef(const SmallVectorImpl<T> &Vec) { 256 return Vec; 257 } 258 259 /// Construct an ArrayRef from a SmallVector. 260 template <typename T, unsigned N> 261 ArrayRef<T> makeArrayRef(const SmallVector<T, N> &Vec) { 262 return Vec; 263 } 264 265 /// Construct an ArrayRef from a std::vector. 266 template<typename T> 267 ArrayRef<T> makeArrayRef(const std::vector<T> &Vec) { 268 return Vec; 269 } 270 271 /// Construct an ArrayRef from a C array. 272 template<typename T, size_t N> 273 ArrayRef<T> makeArrayRef(const T (&Arr)[N]) { 274 return ArrayRef<T>(Arr); 275 } 276 277 /// @} 278 /// @name ArrayRef Comparison Operators 279 /// @{ 280 281 template<typename T> 282 inline bool operator==(ArrayRef<T> LHS, ArrayRef<T> RHS) { 283 return LHS.equals(RHS); 284 } 285 286 template<typename T> 287 inline bool operator!=(ArrayRef<T> LHS, ArrayRef<T> RHS) { 288 return !(LHS == RHS); 289 } 290 291 /// @} 292 293 // ArrayRefs can be treated like a POD type. 294 template <typename T> struct isPodLike; 295 template <typename T> struct isPodLike<ArrayRef<T> > { 296 static const bool value = true; 297 }; 298} 299 300#endif 301