// Copyright (C) 2018-2021  Nexedi SA and Contributors.
//                          Kirill Smelkov <kirr@nexedi.com>
//
// This program is free software: you can Use, Study, Modify and Redistribute
// it under the terms of the GNU General Public License version 3, or (at your
// option) any later version, as published by the Free Software Foundation.
//
// You can also Link and Combine this program with other software covered by
// the terms of any of the Free Software licenses or any of the Open Source
// Initiative approved licenses and Convey the resulting work. Corresponding
// source of such a combination shall include the source code for all other
// software used.
//
// This program is distributed WITHOUT ANY WARRANTY; without even the implied
// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
//
// See COPYING file for full licensing terms.
// See https://www.nexedi.com/licensing for rationale and options.

// Package xtail provides utilities that are common to ΔBtail and ΔFtail.
package xtail

import (
	"fmt"

	"lab.nexedi.com/kirr/neo/go/zodb"
)


// AssertSlice asserts that δ.tail ≤ lo ≤ hi ≤ δ.head
func AssertSlice(δ interface { Head() zodb.Tid; Tail() zodb.Tid }, lo, hi zodb.Tid) {
	tail := δ.Tail()
	head := δ.Head()
	if !(tail <= lo && lo <= hi && hi <= head) {
		panic(fmt.Sprintf("invalid slice: (%s, %s];  (tail, head] = (%s, %s]", lo, hi, tail, head))
	}
}
