1/*
2 * util/rfc_1982.h - RFC 1982 Serial Number Arithmetic
3 *
4 * Copyright (c) 2023, NLnet Labs. All rights reserved.
5 *
6 * This software is open source.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
14 *
15 * Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
18 *
19 * Neither the name of the NLNET LABS nor the names of its contributors may
20 * be used to endorse or promote products derived from this software without
21 * specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36/**
37 * \file
38 *
39 * This file contains functions for RFC 1982 serial number arithmetic.
40 */
41#ifndef RFC_1982_H
42#define RFC_1982_H
43
44/**
45 * RFC 1982 comparison, uses unsigned integers, and tries to avoid
46 * compiler optimization (eg. by avoiding a-b<0 comparisons).
47 * @param a: value to compare.
48 * @param b: value to compare.
49 * @return 0 if equal, 1 if a > b, else -1.
50 */
51int compare_1982(uint32_t a, uint32_t b);
52
53/**
54 * RFC 1982 subtraction, uses unsigned integers, and tries to avoid
55 * compiler optimization (eg. by avoiding a-b<0 comparisons).
56 * @param a: value to subtract from.
57 * @param b: value to subtract.
58 * @return the difference between them if we know that b is larger than a,
59 *	that is the distance between them in serial number arithmetic.
60 */
61uint32_t subtract_1982(uint32_t a, uint32_t b);
62
63#endif /* RFC_1982_H */
64