/src/unbound/util/rfc_1982.c
Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * util/rfc_1982.c - 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, |
28 | | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED |
29 | | * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
30 | | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
31 | | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
32 | | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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 | | #include "config.h" |
42 | | #include "util/rfc_1982.h" |
43 | | |
44 | | int |
45 | | compare_1982(uint32_t a, uint32_t b) |
46 | 0 | { |
47 | | /* for 32 bit values */ |
48 | 0 | const uint32_t cutoff = ((uint32_t) 1 << (32 - 1)); |
49 | |
|
50 | 0 | if (a == b) { |
51 | 0 | return 0; |
52 | 0 | } else if ((a < b && b - a < cutoff) || (a > b && a - b > cutoff)) { |
53 | 0 | return -1; |
54 | 0 | } else { |
55 | 0 | return 1; |
56 | 0 | } |
57 | 0 | } |
58 | | |
59 | | uint32_t |
60 | | subtract_1982(uint32_t a, uint32_t b) |
61 | 0 | { |
62 | | /* for 32 bit values */ |
63 | 0 | const uint32_t cutoff = ((uint32_t) 1 << (32 - 1)); |
64 | |
|
65 | 0 | if(a == b) |
66 | 0 | return 0; |
67 | 0 | if(a < b && b - a < cutoff) { |
68 | 0 | return b-a; |
69 | 0 | } |
70 | 0 | if(a > b && a - b > cutoff) { |
71 | 0 | return ((uint32_t)0xffffffff) - (a-b-1); |
72 | 0 | } |
73 | | /* wrong case, b smaller than a */ |
74 | 0 | return 0; |
75 | 0 | } |