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1e2aae8095
The idea is to avoid std::map lookup for each CellRef. Instead generate a sequence of added and removed RefNums into a vector then order them by RefNum using a stable sort that preserves relative order of elements with the same RefNum. RefIDs are stored in a different vector to avoid std::string move ctor calls when swapping elements while sorting. Reversed iteration over added and removed RefNums for each unique RefNum is an equivalent to what map-based algorithm produces. The main benefit from sorting a vector is a data locality that means less cache misses for each access. Reduces ESMStore::countRecords perf cycles by 25%.
36 lines
904 B
C++
36 lines
904 B
C++
#ifndef OPENMW_COMPONENTS_MISC_ALGORITHM_H
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#define OPENMW_COMPONENTS_MISC_ALGORITHM_H
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#include <iterator>
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#include <type_traits>
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namespace Misc
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{
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template <typename Iterator, typename BinaryPredicate, typename Function>
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inline Iterator forEachUnique(Iterator begin, Iterator end, BinaryPredicate predicate, Function function)
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{
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static_assert(
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std::is_base_of_v<
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std::forward_iterator_tag,
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typename std::iterator_traits<Iterator>::iterator_category
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>
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);
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if (begin == end)
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return begin;
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function(*begin);
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auto last = begin;
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++begin;
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while (begin != end)
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{
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if (!predicate(*begin, *last))
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{
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function(*begin);
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last = begin;
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}
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++begin;
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}
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return begin;
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}
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}
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#endif
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