Files
scylladb/combine.hh
Avi Kivity 5dbfe39399 Add combine() template
Similar to std::merge(), merges two sorted sequences. Duplicates, however,
are merged using a binary function parameter rather than duplicated.
2015-03-05 18:11:37 +02:00

42 lines
1.0 KiB
C++

/*
* Copyright (C) 2015 Cloudius Systems, Ltd.
*/
#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;
}