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Implement correct const iterator for DeallocatingVector

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This commit is contained in:
Patrick Niklaus 2015-07-04 14:29:30 +02:00
parent 2621f4a2fa
commit c2f0e4f683
1 changed files with 76 additions and 1 deletions
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77
data_structures/deallocating_vector.hpp
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@ -36,6 +36,32 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <utility>
#include <vector>
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()
@ -62,6 +88,55 @@ template <typename ElementT> struct DeallocatingVectorIteratorState
}
};
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>,
@ -170,7 +245,7 @@ class DeallocatingVector
public:
using iterator = DeallocatingVectorIterator<ElementT, ELEMENTS_PER_BLOCK>;
using const_iterator = DeallocatingVectorIterator<ElementT, ELEMENTS_PER_BLOCK>;
using const_iterator = ConstDeallocatingVectorIterator<ElementT, ELEMENTS_PER_BLOCK>;
// this forward-only iterator deallocates all buckets that have been visited
using deallocation_iterator = DeallocatingVectorRemoveIterator<ElementT, ELEMENTS_PER_BLOCK>;