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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_BASE_DCHECKED_VECTOR_H_
     18 #define ART_RUNTIME_BASE_DCHECKED_VECTOR_H_
     19 
     20 #include <algorithm>
     21 #include <type_traits>
     22 #include <vector>
     23 
     24 #include "base/logging.h"
     25 
     26 namespace art {
     27 
     28 // Template class serving as a replacement for std::vector<> but adding
     29 // DCHECK()s for the subscript operator, front(), back(), pop_back(),
     30 // and for insert()/emplace()/erase() positions.
     31 //
     32 // Note: The element accessor at() is specified as throwing std::out_of_range
     33 // but we do not use exceptions, so this accessor is deliberately hidden.
     34 // Note: The common pattern &v[0] used to retrieve pointer to the data is not
     35 // valid for an empty dchecked_vector<>. Use data() to avoid checking empty().
     36 template <typename T, typename Alloc = std::allocator<T>>
     37 class dchecked_vector : private std::vector<T, Alloc> {
     38  private:
     39   // std::vector<> has a slightly different specialization for bool. We don't provide that.
     40   static_assert(!std::is_same<T, bool>::value, "Not implemented for bool.");
     41   using Base = std::vector<T, Alloc>;
     42 
     43  public:
     44   using typename Base::value_type;
     45   using typename Base::allocator_type;
     46   using typename Base::reference;
     47   using typename Base::const_reference;
     48   using typename Base::pointer;
     49   using typename Base::const_pointer;
     50   using typename Base::iterator;
     51   using typename Base::const_iterator;
     52   using typename Base::reverse_iterator;
     53   using typename Base::const_reverse_iterator;
     54   using typename Base::size_type;
     55   using typename Base::difference_type;
     56 
     57   // Construct/copy/destroy.
     58   dchecked_vector()
     59       : Base() { }
     60   explicit dchecked_vector(const allocator_type& alloc)
     61       : Base(alloc) { }
     62   // Note that we cannot forward to std::vector(size_type, const allocator_type&) because it is not
     63   // available in C++11, which is the latest GCC can support. http://b/25022512
     64   explicit dchecked_vector(size_type n, const allocator_type& alloc = allocator_type())
     65       : Base(alloc) { resize(n); }
     66   dchecked_vector(size_type n,
     67                   const value_type& value,
     68                   const allocator_type& alloc = allocator_type())
     69       : Base(n, value, alloc) { }
     70   template <typename InputIterator>
     71   dchecked_vector(InputIterator first,
     72                   InputIterator last,
     73                   const allocator_type& alloc = allocator_type())
     74       : Base(first, last, alloc) { }
     75   dchecked_vector(const dchecked_vector& src)
     76       : Base(src) { }
     77   dchecked_vector(const dchecked_vector& src, const allocator_type& alloc)
     78       : Base(src, alloc) { }
     79   dchecked_vector(dchecked_vector&& src)
     80       : Base(std::move(src)) { }
     81   dchecked_vector(dchecked_vector&& src, const allocator_type& alloc)
     82       : Base(std::move(src), alloc) { }
     83   dchecked_vector(std::initializer_list<value_type> il,
     84                   const allocator_type& alloc = allocator_type())
     85       : Base(il, alloc) { }
     86   ~dchecked_vector() = default;
     87   dchecked_vector& operator=(const dchecked_vector& src) {
     88     Base::operator=(src);
     89     return *this;
     90   }
     91   dchecked_vector& operator=(dchecked_vector&& src) {
     92     Base::operator=(std::move(src));
     93     return *this;
     94   }
     95   dchecked_vector& operator=(std::initializer_list<value_type> il) {
     96     Base::operator=(il);
     97     return *this;
     98   }
     99 
    100   // Iterators.
    101   using Base::begin;
    102   using Base::end;
    103   using Base::rbegin;
    104   using Base::rend;
    105   using Base::cbegin;
    106   using Base::cend;
    107   using Base::crbegin;
    108   using Base::crend;
    109 
    110   // Capacity.
    111   using Base::size;
    112   using Base::max_size;
    113   using Base::resize;
    114   using Base::capacity;
    115   using Base::empty;
    116   using Base::reserve;
    117   using Base::shrink_to_fit;
    118 
    119   // Element access: inherited.
    120   // Note: Deliberately not providing at().
    121   using Base::data;
    122 
    123   // Element access: subscript operator. Check index.
    124   reference operator[](size_type n) {
    125     DCHECK_LT(n, size());
    126     return Base::operator[](n);
    127   }
    128   const_reference operator[](size_type n) const {
    129     DCHECK_LT(n, size());
    130     return Base::operator[](n);
    131   }
    132 
    133   // Element access: front(), back(). Check not empty.
    134   reference front() { DCHECK(!empty()); return Base::front(); }
    135   const_reference front() const { DCHECK(!empty()); return Base::front(); }
    136   reference back() { DCHECK(!empty()); return Base::back(); }
    137   const_reference back() const { DCHECK(!empty()); return Base::back(); }
    138 
    139   // Modifiers: inherited.
    140   using Base::assign;
    141   using Base::push_back;
    142   using Base::clear;
    143   using Base::emplace_back;
    144 
    145   // Modifiers: pop_back(). Check not empty.
    146   void pop_back() { DCHECK(!empty()); Base::pop_back(); }
    147 
    148   // Modifiers: swap(). Swap only with another dchecked_vector instead of a plain vector.
    149   void swap(dchecked_vector& other) { Base::swap(other); }
    150 
    151   // Modifiers: insert(). Check position.
    152   iterator insert(const_iterator position, const value_type& value) {
    153     DCHECK(cbegin() <= position && position <= cend());
    154     return Base::insert(position, value);
    155   }
    156   iterator insert(const_iterator position, size_type n, const value_type& value) {
    157     DCHECK(cbegin() <= position && position <= cend());
    158     return Base::insert(position, n, value);
    159   }
    160   template <typename InputIterator>
    161   iterator insert(const_iterator position, InputIterator first, InputIterator last) {
    162     DCHECK(cbegin() <= position && position <= cend());
    163     return Base::insert(position, first, last);
    164   }
    165   iterator insert(const_iterator position, value_type&& value) {
    166     DCHECK(cbegin() <= position && position <= cend());
    167     return Base::insert(position, std::move(value));
    168   }
    169   iterator insert(const_iterator position, std::initializer_list<value_type> il) {
    170     DCHECK(cbegin() <= position && position <= cend());
    171     return Base::insert(position, il);
    172   }
    173 
    174   // Modifiers: erase(). Check position.
    175   iterator erase(const_iterator position) {
    176     DCHECK(cbegin() <= position && position < cend());
    177     return Base::erase(position);
    178   }
    179   iterator erase(const_iterator first, const_iterator last) {
    180     DCHECK(cbegin() <= first && first <= cend());
    181     DCHECK(first <= last && last <= cend());
    182     return Base::erase(first, last);
    183   }
    184 
    185   // Modifiers: emplace(). Check position.
    186   template <typename... Args>
    187   iterator emplace(const_iterator position, Args&&... args) {
    188     DCHECK(cbegin() <= position && position <= cend());
    189     Base::emplace(position, std::forward(args...));
    190   }
    191 
    192   // Allocator.
    193   using Base::get_allocator;
    194 };
    195 
    196 // Non-member swap(), found by argument-dependent lookup for an unqualified call.
    197 template <typename T, typename Alloc>
    198 void swap(dchecked_vector<T, Alloc>& lhs, dchecked_vector<T, Alloc>& rhs) {
    199   lhs.swap(rhs);
    200 }
    201 
    202 // Non-member relational operators.
    203 template <typename T, typename Alloc>
    204 bool operator==(const dchecked_vector<T, Alloc>& lhs, const dchecked_vector<T, Alloc>& rhs) {
    205   return lhs.size() == rhs.size() && std::equal(lhs.begin(), lhs.end(), rhs.begin());
    206 }
    207 template <typename T, typename Alloc>
    208 bool operator!=(const dchecked_vector<T, Alloc>& lhs, const dchecked_vector<T, Alloc>& rhs) {
    209   return !(lhs == rhs);
    210 }
    211 template <typename T, typename Alloc>
    212 bool operator<(const dchecked_vector<T, Alloc>& lhs, const dchecked_vector<T, Alloc>& rhs) {
    213   return std::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
    214 }
    215 template <typename T, typename Alloc>
    216 bool operator<=(const dchecked_vector<T, Alloc>& lhs, const dchecked_vector<T, Alloc>& rhs) {
    217   return !(rhs < lhs);
    218 }
    219 template <typename T, typename Alloc>
    220 bool operator>(const dchecked_vector<T, Alloc>& lhs, const dchecked_vector<T, Alloc>& rhs) {
    221   return rhs < lhs;
    222 }
    223 template <typename T, typename Alloc>
    224 bool operator>=(const dchecked_vector<T, Alloc>& lhs, const dchecked_vector<T, Alloc>& rhs) {
    225   return !(lhs < rhs);
    226 }
    227 
    228 }  // namespace art
    229 
    230 #endif  // ART_RUNTIME_BASE_DCHECKED_VECTOR_H_
    231