xref: /dokuwiki/vendor/paragonie/constant_time_encoding/src/Base32Hex.php (revision 8e88a29b81301f78509349ab1152bb09c229123e) 
1<?php
2declare(strict_types=1);
3namespace ParagonIE\ConstantTime;
4
5use Override;
6use function pack;
7
8/**
9 *  Copyright (c) 2016 - 2022 Paragon Initiative Enterprises.
10 *  Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
11 *
12 *  Permission is hereby granted, free of charge, to any person obtaining a copy
13 *  of this software and associated documentation files (the "Software"), to deal
14 *  in the Software without restriction, including without limitation the rights
15 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
16 *  copies of the Software, and to permit persons to whom the Software is
17 *  furnished to do so, subject to the following conditions:
18 *
19 *  The above copyright notice and this permission notice shall be included in all
20 *  copies or substantial portions of the Software.
21 *
22 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
27 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
28 *  SOFTWARE.
29 */
30
31/**
32 * Class Base32Hex
33 * [0-9][A-V]
34 *
35 * @package ParagonIE\ConstantTime
36 */
37abstract class Base32Hex extends Base32
38{
39    /**
40     * Uses bitwise operators instead of table-lookups to turn 5-bit integers
41     * into 8-bit integers.
42     *
43     * @param int $src
44     * @return int
45     */
46    #[Override]
47    protected static function decode5Bits(int $src): int
48    {
49        $ret = -1;
50
51        // if ($src > 0x30 && $src < 0x3a) ret += $src - 0x2e + 1; // -47
52        $ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src - 47);
53
54        // if ($src > 0x60 && $src < 0x77) ret += $src - 0x61 + 10 + 1; // -86
55        $ret += (((0x60 - $src) & ($src - 0x77)) >> 8) & ($src - 86);
56
57        return $ret;
58    }
59
60    /**
61     * Uses bitwise operators instead of table-lookups to turn 5-bit integers
62     * into 8-bit integers.
63     *
64     * @param int $src
65     * @return int
66     */
67    #[Override]
68    protected static function decode5BitsUpper(int $src): int
69    {
70        $ret = -1;
71
72        // if ($src > 0x30 && $src < 0x3a) ret += $src - 0x2e + 1; // -47
73        $ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src - 47);
74
75        // if ($src > 0x40 && $src < 0x57) ret += $src - 0x41 + 10 + 1; // -54
76        $ret += (((0x40 - $src) & ($src - 0x57)) >> 8) & ($src - 54);
77
78        return $ret;
79    }
80
81    /**
82     * Uses bitwise operators instead of table-lookups to turn 8-bit integers
83     * into 5-bit integers.
84     *
85     * @param int $src
86     * @return string
87     */
88    #[Override]
89    protected static function encode5Bits(int $src): string
90    {
91        $src += 0x30;
92
93        // if ($src > 0x39) $src += 0x61 - 0x3a; // 39
94        $src += ((0x39 - $src) >> 8) & 39;
95
96        return pack('C', $src);
97    }
98
99    /**
100     * Uses bitwise operators instead of table-lookups to turn 8-bit integers
101     * into 5-bit integers.
102     *
103     * Uppercase variant.
104     *
105     * @param int $src
106     * @return string
107     */
108    #[Override]
109    protected static function encode5BitsUpper(int $src): string
110    {
111        $src += 0x30;
112
113        // if ($src > 0x39) $src += 0x41 - 0x3a; // 7
114        $src += ((0x39 - $src) >> 8) & 7;
115
116        return pack('C', $src);
117    }
118}