#!/bin/sh -e
#
# 0044interval_overlap_1 - Single-sized intervals can never overlap partially
#
# Check that inserting, deleting, and inserting single-sized intervals again
# never leads to a partial overlap. Specifically trigger rbtree rebalancing in
# the process, to ensure different tree shapes of equivalent sets don't lead to
# false positives, by deleting every second inserted item.

xorshift() {
	# Adaptation of Xorshift algorithm from:
	#   Marsaglia, G. (2003). Xorshift RNGs.
	#   Journal of Statistical Software, 8(14), 1 - 6.
	#   doi:http://dx.doi.org/10.18637/jss.v008.i14
	# with triplet (5, 3, 1), suitable for 16-bit ranges.

	: $((port ^= port << 5))
	: $((port ^= port >> 3))
	: $((port ^= port << 1))
}

$NFT add table t
$NFT add set t s '{ type inet_service ; flags interval ; }'

for op in add delete add; do
	port=1
	skip=0
	for i in $(seq 1 500); do
		xorshift
		if [ "${op}" = "delete" ]; then
			[ ${skip} -eq 0 ] && skip=1 && continue
			skip=0
		fi
		$NFT ${op} element t s "{ { $((port % 32768 + 32768)) } }"
	done
done