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combine.hh
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combine.hh
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/*
* Copyright (C) 2015 Cloudius Systems, Ltd.
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
// combine two sorted uniqued sequences into a single sorted sequence
// unique elements are copied, duplicate elements are merged with a
// binary function.
template <typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename Compare,
typename Merge>
OutputIterator
combine(InputIterator1 begin1, InputIterator1 end1,
InputIterator2 begin2, InputIterator2 end2,
OutputIterator out,
Compare compare,
Merge merge) {
while (begin1 != end1 && begin2 != end2) {
auto& e1 = *begin1;
auto& e2 = *begin2;
if (compare(e1, e2)) {
*out++ = e1;
++begin1;
} else if (compare(e2, e1)) {
*out++ = e2;
++begin2;
} else {
*out++ = merge(e1, e2);
++begin1;
++begin2;
}
}
out = std::copy(begin1, end1, out);
out = std::copy(begin2, end2, out);
return out;
}