exduckdb

#include "duckdb/common/operator/comparison_operators.hpp"
#include "duckdb/common/vector_operations/vector_operations.hpp"
#include "duckdb/execution/merge_join.hpp"
#include "duckdb/parser/expression/comparison_expression.hpp"

namespace duckdb {

template <class T, class OP>
idx_t MergeJoinComplexLessThan(ScalarMergeInfo &l, ScalarMergeInfo &r) {
	if (r.pos >= r.order.count) {
		return 0;
	}
	auto ldata = (T *)l.order.vdata.data;
	auto rdata = (T *)r.order.vdata.data;
	auto &lorder = l.order.order;
	auto &rorder = r.order.order;
	idx_t result_count = 0;
	while (true) {
		if (l.pos < l.order.count) {
			auto lidx = lorder.get_index(l.pos);
			auto ridx = rorder.get_index(r.pos);
			auto dlidx = l.order.vdata.sel->get_index(lidx);
			auto dridx = r.order.vdata.sel->get_index(ridx);
			if (OP::Operation(ldata[dlidx], rdata[dridx])) {
				// left side smaller: found match
				l.result.set_index(result_count, lidx);
				r.result.set_index(result_count, ridx);
				result_count++;
				// move left side forward
				l.pos++;
				if (result_count == STANDARD_VECTOR_SIZE) {
					// out of space!
					break;
				}
				continue;
			}
		}
		// right side smaller or equal, or left side exhausted: move
		// right pointer forward reset left side to start
		l.pos = 0;
		r.pos++;
		if (r.pos == r.order.count) {
			break;
		}
	}
	return result_count;
}

template <class T>
idx_t MergeJoinComplex::LessThan::Operation(ScalarMergeInfo &l, ScalarMergeInfo &r) {
	return MergeJoinComplexLessThan<T, duckdb::LessThan>(l, r);
}

template <class T>
idx_t MergeJoinComplex::LessThanEquals::Operation(ScalarMergeInfo &l, ScalarMergeInfo &r) {
	return MergeJoinComplexLessThan<T, duckdb::LessThanEquals>(l, r);
}

INSTANTIATE_MERGEJOIN_TEMPLATES(MergeJoinComplex, LessThan, ScalarMergeInfo, ScalarMergeInfo)
INSTANTIATE_MERGEJOIN_TEMPLATES(MergeJoinComplex, LessThanEquals, ScalarMergeInfo, ScalarMergeInfo)

} // namespace duckdb