osrm-backend/include/util/deallocating_vector.hpp

353 lines
11 KiB
C++

#ifndef DEALLOCATING_VECTOR_HPP
#define DEALLOCATING_VECTOR_HPP
#include "storage/io_fwd.hpp"
#include "util/integer_range.hpp"
#include <boost/iterator/iterator_facade.hpp>
#include <algorithm>
#include <limits>
#include <utility>
#include <vector>
namespace osrm::util
{
template <typename ElementT> struct ConstDeallocatingVectorIteratorState
{
ConstDeallocatingVectorIteratorState()
: index(std::numeric_limits<std::size_t>::max()), bucket_list(nullptr)
{
}
explicit ConstDeallocatingVectorIteratorState(const ConstDeallocatingVectorIteratorState &r)
: index(r.index), bucket_list(r.bucket_list)
{
}
explicit ConstDeallocatingVectorIteratorState(const std::size_t idx,
const std::vector<ElementT *> *input_list)
: index(idx), bucket_list(input_list)
{
}
std::size_t index;
const std::vector<ElementT *> *bucket_list;
ConstDeallocatingVectorIteratorState &
operator=(const ConstDeallocatingVectorIteratorState &other)
{
index = other.index;
bucket_list = other.bucket_list;
return *this;
}
};
template <typename ElementT> struct DeallocatingVectorIteratorState
{
DeallocatingVectorIteratorState()
: index(std::numeric_limits<std::size_t>::max()), bucket_list(nullptr)
{
}
explicit DeallocatingVectorIteratorState(const DeallocatingVectorIteratorState &r)
: index(r.index), bucket_list(r.bucket_list)
{
}
explicit DeallocatingVectorIteratorState(const std::size_t idx,
std::vector<ElementT *> *input_list)
: index(idx), bucket_list(input_list)
{
}
std::size_t index;
std::vector<ElementT *> *bucket_list;
DeallocatingVectorIteratorState &operator=(const DeallocatingVectorIteratorState &other)
{
index = other.index;
bucket_list = other.bucket_list;
return *this;
}
};
template <typename ElementT, std::size_t ELEMENTS_PER_BLOCK>
class ConstDeallocatingVectorIterator
: public boost::iterator_facade<ConstDeallocatingVectorIterator<ElementT, ELEMENTS_PER_BLOCK>,
ElementT,
std::random_access_iterator_tag>
{
ConstDeallocatingVectorIteratorState<ElementT> current_state;
public:
ConstDeallocatingVectorIterator() {}
ConstDeallocatingVectorIterator(std::size_t idx, const std::vector<ElementT *> *input_list)
: current_state(idx, input_list)
{
}
friend class boost::iterator_core_access;
void advance(std::size_t n) { current_state.index += n; }
void increment() { advance(1); }
void decrement() { advance(-1); }
bool equal(ConstDeallocatingVectorIterator const &other) const
{
return current_state.index == other.current_state.index;
}
std::ptrdiff_t distance_to(ConstDeallocatingVectorIterator const &other) const
{
// it is important to implement it 'other minus this'. otherwise sorting breaks
return other.current_state.index - current_state.index;
}
ElementT &dereference() const
{
const std::size_t current_bucket = current_state.index / ELEMENTS_PER_BLOCK;
const std::size_t current_index = current_state.index % ELEMENTS_PER_BLOCK;
return (current_state.bucket_list->at(current_bucket)[current_index]);
}
ElementT &operator[](const std::size_t index) const
{
const std::size_t current_bucket = (index + current_state.index) / ELEMENTS_PER_BLOCK;
const std::size_t current_index = (index + current_state.index) % ELEMENTS_PER_BLOCK;
return (current_state.bucket_list->at(current_bucket)[current_index]);
}
};
template <typename ElementT, std::size_t ELEMENTS_PER_BLOCK>
class DeallocatingVectorIterator
: public boost::iterator_facade<DeallocatingVectorIterator<ElementT, ELEMENTS_PER_BLOCK>,
ElementT,
std::random_access_iterator_tag>
{
DeallocatingVectorIteratorState<ElementT> current_state;
public:
DeallocatingVectorIterator() {}
DeallocatingVectorIterator(std::size_t idx, std::vector<ElementT *> *input_list)
: current_state(idx, input_list)
{
}
friend class boost::iterator_core_access;
void advance(std::size_t n) { current_state.index += n; }
void increment() { advance(1); }
void decrement() { advance(-1); }
bool equal(DeallocatingVectorIterator const &other) const
{
return current_state.index == other.current_state.index;
}
std::ptrdiff_t distance_to(DeallocatingVectorIterator const &other) const
{
// it is important to implement it 'other minus this'. otherwise sorting breaks
return other.current_state.index - current_state.index;
}
ElementT &dereference() const
{
const std::size_t current_bucket = current_state.index / ELEMENTS_PER_BLOCK;
const std::size_t current_index = current_state.index % ELEMENTS_PER_BLOCK;
return (current_state.bucket_list->at(current_bucket)[current_index]);
}
ElementT &operator[](const std::size_t index) const
{
const std::size_t current_bucket = (index + current_state.index) / ELEMENTS_PER_BLOCK;
const std::size_t current_index = (index + current_state.index) % ELEMENTS_PER_BLOCK;
return (current_state.bucket_list->at(current_bucket)[current_index]);
}
};
template <typename ElementT> class DeallocatingVector;
template <typename T> void swap(DeallocatingVector<T> &lhs, DeallocatingVector<T> &rhs) noexcept;
template <typename ElementT> class DeallocatingVector
{
static constexpr std::size_t ELEMENTS_PER_BLOCK = 8388608 / sizeof(ElementT);
std::size_t current_size;
std::vector<ElementT *> bucket_list;
public:
using value_type = ElementT;
using iterator = DeallocatingVectorIterator<ElementT, ELEMENTS_PER_BLOCK>;
using const_iterator = ConstDeallocatingVectorIterator<ElementT, ELEMENTS_PER_BLOCK>;
DeallocatingVector() : current_size(0)
{
bucket_list.emplace_back(new ElementT[ELEMENTS_PER_BLOCK]);
}
// Performs a deep copy of the buckets
DeallocatingVector(const DeallocatingVector &other)
{
bucket_list.resize(other.bucket_list.size());
for (const auto index : util::irange<std::size_t>(0, bucket_list.size()))
{
bucket_list[index] = new ElementT[ELEMENTS_PER_BLOCK];
std::copy_n(other.bucket_list[index], ELEMENTS_PER_BLOCK, bucket_list[index]);
}
current_size = other.current_size;
}
// Note we capture other by value
DeallocatingVector &operator=(const DeallocatingVector &other)
{
auto copy_other = other;
swap(copy_other);
return *this;
}
// moving is fine
DeallocatingVector(DeallocatingVector &&other) noexcept { swap(other); }
DeallocatingVector &operator=(DeallocatingVector &&other) noexcept
{
swap(other);
return *this;
}
DeallocatingVector(std::initializer_list<ElementT> elements) : DeallocatingVector()
{
for (auto &&elem : elements)
{
emplace_back(std::move(elem));
}
}
~DeallocatingVector() { clear(); }
friend void swap<>(DeallocatingVector<ElementT> &lhs,
DeallocatingVector<ElementT> &rhs) noexcept;
void swap(DeallocatingVector<ElementT> &other) noexcept
{
std::swap(current_size, other.current_size);
bucket_list.swap(other.bucket_list);
}
void clear()
{
// Delete[]'ing ptr's to all Buckets
for (auto bucket : bucket_list)
{
delete[] bucket;
}
bucket_list.clear();
bucket_list.shrink_to_fit();
current_size = 0;
}
void push_back(const ElementT &element)
{
const std::size_t current_capacity = capacity();
if (current_size == current_capacity)
{
bucket_list.push_back(new ElementT[ELEMENTS_PER_BLOCK]);
}
std::size_t current_index = size() % ELEMENTS_PER_BLOCK;
bucket_list.back()[current_index] = element;
++current_size;
}
template <typename... Ts> void emplace_back(Ts &&...element)
{
const std::size_t current_capacity = capacity();
if (current_size == current_capacity)
{
bucket_list.push_back(new ElementT[ELEMENTS_PER_BLOCK]);
}
const std::size_t current_index = size() % ELEMENTS_PER_BLOCK;
bucket_list.back()[current_index] = ElementT(std::forward<Ts>(element)...);
++current_size;
}
void reserve(const std::size_t) const
{ /* don't do anything */
}
void resize(const std::size_t new_size)
{
if (new_size >= current_size)
{
while (capacity() < new_size)
{
bucket_list.push_back(new ElementT[ELEMENTS_PER_BLOCK]);
}
}
else
{ // down-size
const std::size_t number_of_necessary_buckets = 1 + (new_size / ELEMENTS_PER_BLOCK);
for (const auto bucket_index : irange(number_of_necessary_buckets, bucket_list.size()))
{
if (nullptr != bucket_list[bucket_index])
{
delete[] bucket_list[bucket_index];
}
}
bucket_list.resize(number_of_necessary_buckets);
}
current_size = new_size;
}
std::size_t size() const { return current_size; }
std::size_t capacity() const { return bucket_list.size() * ELEMENTS_PER_BLOCK; }
iterator begin() { return iterator(static_cast<std::size_t>(0), &bucket_list); }
iterator end() { return iterator(size(), &bucket_list); }
const_iterator begin() const
{
return const_iterator(static_cast<std::size_t>(0), &bucket_list);
}
const_iterator end() const { return const_iterator(size(), &bucket_list); }
ElementT &operator[](const std::size_t index)
{
const std::size_t _bucket = index / ELEMENTS_PER_BLOCK;
const std::size_t _index = index % ELEMENTS_PER_BLOCK;
return (bucket_list[_bucket][_index]);
}
ElementT &operator[](const std::size_t index) const
{
const std::size_t _bucket = index / ELEMENTS_PER_BLOCK;
const std::size_t _index = index % ELEMENTS_PER_BLOCK;
return (bucket_list[_bucket][_index]);
}
ElementT &back() const
{
const std::size_t _bucket = (current_size - 1) / ELEMENTS_PER_BLOCK;
const std::size_t _index = (current_size - 1) % ELEMENTS_PER_BLOCK;
return (bucket_list[_bucket][_index]);
}
template <class InputIterator> void append(InputIterator first, const InputIterator last)
{
InputIterator position = first;
while (position != last)
{
push_back(*position);
++position;
}
}
};
template <typename T> void swap(DeallocatingVector<T> &lhs, DeallocatingVector<T> &rhs) noexcept
{
lhs.swap(rhs);
}
} // namespace osrm::util
#endif /* DEALLOCATING_VECTOR_HPP */