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1d42c4f6de
Per XLS-0095, we are taking steps to rename ripple(d) to xrpl(d). This change specifically removes all copyright notices referencing Ripple, XRPLF, and certain affiliated contributors upon mutual agreement, so the notice in the LICENSE.md file applies throughout. Copyright notices referencing external contributions remain as-is. Duplicate verbiage is also removed.
101 lines
3.2 KiB
C++
101 lines
3.2 KiB
C++
#ifndef XRPL_ALGORITHM_H_INCLUDED
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#define XRPL_ALGORITHM_H_INCLUDED
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#include <utility>
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namespace ripple {
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// Requires: [first1, last1) and [first2, last2) are ordered ranges according to
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// comp.
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// Effects: For each pair of elements {i, j} in the intersection of the sorted
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// sequences [first1, last1) and [first2, last2), perform action(i, j).
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// Note: This algorithm is evolved from std::set_intersection.
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template <class InputIter1, class InputIter2, class Action, class Comp>
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void
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generalized_set_intersection(
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InputIter1 first1,
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InputIter1 last1,
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InputIter2 first2,
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InputIter2 last2,
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Action action,
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Comp comp)
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{
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while (first1 != last1 && first2 != last2)
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{
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if (comp(*first1, *first2)) // if *first1 < *first2
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++first1; // then reduce first range
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else
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{
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if (!comp(*first2, *first1)) // if *first1 == *first2
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{ // then this is an intersection
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action(*first1, *first2); // do the action
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++first1; // reduce first range
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}
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++first2; // Reduce second range because *first2 <= *first1
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}
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}
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}
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// Requires: [first1, last1) and [first2, last2) are ordered ranges according to
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// comp.
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// Effects: Eliminates all the elements i in the range [first1, last1) which are
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// equivalent to some value in [first2, last2) or for which pred(i) returns
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// true.
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// Returns: A FwdIter1 E such that [first1, E) is the range of elements not
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// removed by this algorithm.
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// Note: This algorithm is evolved from std::remove_if and
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// std::set_intersection.
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template <class FwdIter1, class InputIter2, class Pred, class Comp>
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FwdIter1
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remove_if_intersect_or_match(
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FwdIter1 first1,
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FwdIter1 last1,
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InputIter2 first2,
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InputIter2 last2,
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Pred pred,
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Comp comp)
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{
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// [original-first1, current-first1) is the set of elements to be preserved.
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// [current-first1, i) is the set of elements that have been removed.
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// [i, last1) is the set of elements not tested yet.
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// Test each *i in [first1, last1) against [first2, last2) and pred
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for (auto i = first1; i != last1;)
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{
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// if (*i is not in [first2, last2)
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if (first2 == last2 || comp(*i, *first2))
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{
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if (!pred(*i))
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{
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// *i should not be removed, so append it to the preserved set
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if (i != first1)
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*first1 = std::move(*i);
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++first1;
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}
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// *i has been fully tested, prepare for next i by
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// appending i to the removed set, whether or not
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// it has been moved from above.
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++i;
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}
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else // *i might be in [first2, last2) because *i >= *first2
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{
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if (!comp(*first2, *i)) // if *i == *first2
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++i; // then append *i to the removed set
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// All elements in [i, last1) are known to be greater than *first2,
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// so reduce the second range.
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++first2;
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}
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// Continue to test *i against [first2, last2) and pred
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}
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return first1;
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}
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} // namespace ripple
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#endif
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