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      1 // Copyright 2014 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef V8_VECTOR_H_
      6 #define V8_VECTOR_H_
      7 
      8 #include <algorithm>
      9 #include <cstring>
     10 #include <iterator>
     11 
     12 #include "src/allocation.h"
     13 #include "src/checks.h"
     14 #include "src/globals.h"
     15 
     16 namespace v8 {
     17 namespace internal {
     18 
     19 
     20 template <typename T>
     21 class Vector {
     22  public:
     23   constexpr Vector() : start_(nullptr), length_(0) {}
     24 
     25   Vector(T* data, size_t length) : start_(data), length_(length) {
     26     DCHECK(length == 0 || data != nullptr);
     27   }
     28 
     29   template <int N>
     30   explicit constexpr Vector(T (&arr)[N]) : start_(arr), length_(N) {}
     31 
     32   static Vector<T> New(int length) {
     33     return Vector<T>(NewArray<T>(length), length);
     34   }
     35 
     36   // Returns a vector using the same backing storage as this one,
     37   // spanning from and including 'from', to but not including 'to'.
     38   Vector<T> SubVector(size_t from, size_t to) const {
     39     DCHECK_LE(from, to);
     40     DCHECK_LE(to, length_);
     41     return Vector<T>(start() + from, to - from);
     42   }
     43 
     44   // Returns the length of the vector.
     45   int length() const {
     46     DCHECK(length_ <= static_cast<size_t>(std::numeric_limits<int>::max()));
     47     return static_cast<int>(length_);
     48   }
     49 
     50   // Returns the length of the vector as a size_t.
     51   constexpr size_t size() const { return length_; }
     52 
     53   // Returns whether or not the vector is empty.
     54   constexpr bool is_empty() const { return length_ == 0; }
     55 
     56   // Returns the pointer to the start of the data in the vector.
     57   constexpr T* start() const { return start_; }
     58 
     59   // Access individual vector elements - checks bounds in debug mode.
     60   T& operator[](size_t index) const {
     61     DCHECK_LT(index, length_);
     62     return start_[index];
     63   }
     64 
     65   const T& at(size_t index) const { return operator[](index); }
     66 
     67   T& first() { return start_[0]; }
     68 
     69   T& last() {
     70     DCHECK_LT(0, length_);
     71     return start_[length_ - 1];
     72   }
     73 
     74   typedef T* iterator;
     75   constexpr iterator begin() const { return start_; }
     76   constexpr iterator end() const { return start_ + length_; }
     77 
     78   // Returns a clone of this vector with a new backing store.
     79   Vector<T> Clone() const {
     80     T* result = NewArray<T>(length_);
     81     for (size_t i = 0; i < length_; i++) result[i] = start_[i];
     82     return Vector<T>(result, length_);
     83   }
     84 
     85   template <typename CompareFunction>
     86   void Sort(CompareFunction cmp, size_t s, size_t l) {
     87     std::sort(start() + s, start() + s + l, RawComparer<CompareFunction>(cmp));
     88   }
     89 
     90   template <typename CompareFunction>
     91   void Sort(CompareFunction cmp) {
     92     std::sort(start(), start() + length(), RawComparer<CompareFunction>(cmp));
     93   }
     94 
     95   void Sort() {
     96     std::sort(start(), start() + length());
     97   }
     98 
     99   template <typename CompareFunction>
    100   void StableSort(CompareFunction cmp, size_t s, size_t l) {
    101     std::stable_sort(start() + s, start() + s + l,
    102                      RawComparer<CompareFunction>(cmp));
    103   }
    104 
    105   template <typename CompareFunction>
    106   void StableSort(CompareFunction cmp) {
    107     std::stable_sort(start(), start() + length(),
    108                      RawComparer<CompareFunction>(cmp));
    109   }
    110 
    111   void StableSort() { std::stable_sort(start(), start() + length()); }
    112 
    113   void Truncate(size_t length) {
    114     DCHECK(length <= length_);
    115     length_ = length;
    116   }
    117 
    118   // Releases the array underlying this vector. Once disposed the
    119   // vector is empty.
    120   void Dispose() {
    121     DeleteArray(start_);
    122     start_ = nullptr;
    123     length_ = 0;
    124   }
    125 
    126   Vector<T> operator+(size_t offset) {
    127     DCHECK_LE(offset, length_);
    128     return Vector<T>(start_ + offset, length_ - offset);
    129   }
    130 
    131   Vector<T> operator+=(size_t offset) {
    132     DCHECK_LE(offset, length_);
    133     start_ += offset;
    134     length_ -= offset;
    135     return *this;
    136   }
    137 
    138   // Implicit conversion from Vector<T> to Vector<const T>.
    139   inline operator Vector<const T>() { return Vector<const T>::cast(*this); }
    140 
    141   // Factory method for creating empty vectors.
    142   static Vector<T> empty() { return Vector<T>(nullptr, 0); }
    143 
    144   template <typename S>
    145   static constexpr Vector<T> cast(Vector<S> input) {
    146     return Vector<T>(reinterpret_cast<T*>(input.start()),
    147                      input.length() * sizeof(S) / sizeof(T));
    148   }
    149 
    150   bool operator==(const Vector<T>& other) const {
    151     if (length_ != other.length_) return false;
    152     if (start_ == other.start_) return true;
    153     for (size_t i = 0; i < length_; ++i) {
    154       if (start_[i] != other.start_[i]) {
    155         return false;
    156       }
    157     }
    158     return true;
    159   }
    160 
    161  private:
    162   T* start_;
    163   size_t length_;
    164 
    165   template <typename CookedComparer>
    166   class RawComparer {
    167    public:
    168     explicit RawComparer(CookedComparer cmp) : cmp_(cmp) {}
    169     bool operator()(const T& a, const T& b) {
    170       return cmp_(&a, &b) < 0;
    171     }
    172 
    173    private:
    174     CookedComparer cmp_;
    175   };
    176 };
    177 
    178 
    179 template <typename T>
    180 class ScopedVector : public Vector<T> {
    181  public:
    182   explicit ScopedVector(int length) : Vector<T>(NewArray<T>(length), length) { }
    183   ~ScopedVector() {
    184     DeleteArray(this->start());
    185   }
    186 
    187  private:
    188   DISALLOW_IMPLICIT_CONSTRUCTORS(ScopedVector);
    189 };
    190 
    191 template <typename T>
    192 class OwnedVector {
    193  public:
    194   MOVE_ONLY_WITH_DEFAULT_CONSTRUCTORS(OwnedVector);
    195   OwnedVector(std::unique_ptr<T[]> data, size_t length)
    196       : data_(std::move(data)), length_(length) {
    197     DCHECK_IMPLIES(length_ > 0, data_ != nullptr);
    198   }
    199   // Implicit conversion from {OwnedVector<U>} to {OwnedVector<T>}, instantiable
    200   // if {std::unique_ptr<U>} can be converted to {std::unique_ptr<T>}.
    201   // Can be used to convert {OwnedVector<T>} to {OwnedVector<const T>}.
    202   template <typename U,
    203             typename = typename std::enable_if<std::is_convertible<
    204                 std::unique_ptr<U>, std::unique_ptr<T>>::value>::type>
    205   OwnedVector(OwnedVector<U>&& other)
    206       : data_(other.ReleaseData()), length_(other.size()) {}
    207 
    208   // Returns the length of the vector as a size_t.
    209   constexpr size_t size() const { return length_; }
    210 
    211   // Returns whether or not the vector is empty.
    212   constexpr bool is_empty() const { return length_ == 0; }
    213 
    214   // Returns the pointer to the start of the data in the vector.
    215   T* start() const {
    216     DCHECK_IMPLIES(length_ > 0, data_ != nullptr);
    217     return data_.get();
    218   }
    219 
    220   // Returns a {Vector<T>} view of the data in this vector.
    221   Vector<T> as_vector() const { return Vector<T>(start(), size()); }
    222 
    223   // Releases the backing data from this vector and transfers ownership to the
    224   // caller. This vectors data can no longer be used afterwards.
    225   std::unique_ptr<T[]> ReleaseData() { return std::move(data_); }
    226 
    227   // Allocates a new vector of the specified size via the default allocator.
    228   static OwnedVector<T> New(size_t size) {
    229     if (size == 0) return {};
    230     return OwnedVector<T>(std::unique_ptr<T[]>(new T[size]), size);
    231   }
    232 
    233   // Allocates a new vector containing the specified collection of values.
    234   // {Iterator} is the common type of {std::begin} and {std::end} called on a
    235   // {const U&}. This function is only instantiable if that type exists.
    236   template <typename U, typename Iterator = typename std::common_type<
    237                             decltype(std::begin(std::declval<const U&>())),
    238                             decltype(std::end(std::declval<const U&>()))>::type>
    239   static OwnedVector<T> Of(const U& collection) {
    240     Iterator begin = std::begin(collection);
    241     Iterator end = std::end(collection);
    242     OwnedVector<T> vec = New(std::distance(begin, end));
    243     std::copy(begin, end, vec.start());
    244     return vec;
    245   }
    246 
    247  private:
    248   std::unique_ptr<T[]> data_;
    249   size_t length_ = 0;
    250 };
    251 
    252 inline int StrLength(const char* string) {
    253   size_t length = strlen(string);
    254   DCHECK(length == static_cast<size_t>(static_cast<int>(length)));
    255   return static_cast<int>(length);
    256 }
    257 
    258 
    259 #define STATIC_CHAR_VECTOR(x)                                              \
    260   v8::internal::Vector<const uint8_t>(reinterpret_cast<const uint8_t*>(x), \
    261                                       arraysize(x) - 1)
    262 
    263 inline Vector<const char> CStrVector(const char* data) {
    264   return Vector<const char>(data, StrLength(data));
    265 }
    266 
    267 inline Vector<const uint8_t> OneByteVector(const char* data, int length) {
    268   return Vector<const uint8_t>(reinterpret_cast<const uint8_t*>(data), length);
    269 }
    270 
    271 inline Vector<const uint8_t> OneByteVector(const char* data) {
    272   return OneByteVector(data, StrLength(data));
    273 }
    274 
    275 inline Vector<char> MutableCStrVector(char* data) {
    276   return Vector<char>(data, StrLength(data));
    277 }
    278 
    279 inline Vector<char> MutableCStrVector(char* data, int max) {
    280   int length = StrLength(data);
    281   return Vector<char>(data, (length < max) ? length : max);
    282 }
    283 
    284 template <typename T, int N>
    285 inline constexpr Vector<T> ArrayVector(T (&arr)[N]) {
    286   return Vector<T>(arr);
    287 }
    288 
    289 }  // namespace internal
    290 }  // namespace v8
    291 
    292 #endif  // V8_VECTOR_H_
    293