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41 lines
881 B
C++
41 lines
881 B
C++
#pragma once
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#include <map>
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#include <optional>
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namespace scwx
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{
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namespace util
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{
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template<class Key, class T>
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std::optional<T> GetBoundedElement(std::map<Key, T>& map, Key key)
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{
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std::optional<T> element = std::nullopt;
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// Find the first element greater than the key requested
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auto it = map.upper_bound(key);
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// An element with a key greater was found
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if (it != map.cend())
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{
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// Are there elements prior to this element?
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if (it != map.cbegin())
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{
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// Get the element immediately preceding, this the element we are
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// looking for
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element = (--it)->second;
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}
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}
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else if (map.size() > 0)
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{
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// An element with a key greater was not found. If it exists, it must be
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// the last element.
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element = map.rbegin()->second;
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}
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return element;
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}
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} // namespace util
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} // namespace scwx
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