1<?php
2declare(strict_types=1);
3namespace ParagonIE\ConstantTime;
4
5/**
6 *  Copyright (c) 2016 - 2018 Paragon Initiative Enterprises.
7 *  Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
8 *
9 *  Permission is hereby granted, free of charge, to any person obtaining a copy
10 *  of this software and associated documentation files (the "Software"), to deal
11 *  in the Software without restriction, including without limitation the rights
12 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 *  copies of the Software, and to permit persons to whom the Software is
14 *  furnished to do so, subject to the following conditions:
15 *
16 *  The above copyright notice and this permission notice shall be included in all
17 *  copies or substantial portions of the Software.
18 *
19 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
25 *  SOFTWARE.
26 */
27
28/**
29 * Class Base32Hex
30 * [0-9][A-V]
31 *
32 * @package ParagonIE\ConstantTime
33 */
34abstract class Base32Hex extends Base32
35{
36    /**
37     * Uses bitwise operators instead of table-lookups to turn 5-bit integers
38     * into 8-bit integers.
39     *
40     * @param int $src
41     * @return int
42     */
43    protected static function decode5Bits(int $src): int
44    {
45        $ret = -1;
46
47        // if ($src > 0x30 && $src < 0x3a) ret += $src - 0x2e + 1; // -47
48        $ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src - 47);
49
50        // if ($src > 0x60 && $src < 0x77) ret += $src - 0x61 + 10 + 1; // -86
51        $ret += (((0x60 - $src) & ($src - 0x77)) >> 8) & ($src - 86);
52
53        return $ret;
54    }
55
56    /**
57     * Uses bitwise operators instead of table-lookups to turn 5-bit integers
58     * into 8-bit integers.
59     *
60     * @param int $src
61     * @return int
62     */
63    protected static function decode5BitsUpper(int $src): int
64    {
65        $ret = -1;
66
67        // if ($src > 0x30 && $src < 0x3a) ret += $src - 0x2e + 1; // -47
68        $ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src - 47);
69
70        // if ($src > 0x40 && $src < 0x57) ret += $src - 0x41 + 10 + 1; // -54
71        $ret += (((0x40 - $src) & ($src - 0x57)) >> 8) & ($src - 54);
72
73        return $ret;
74    }
75
76    /**
77     * Uses bitwise operators instead of table-lookups to turn 8-bit integers
78     * into 5-bit integers.
79     *
80     * @param int $src
81     * @return string
82     */
83    protected static function encode5Bits(int $src): string
84    {
85        $src += 0x30;
86
87        // if ($src > 0x39) $src += 0x61 - 0x3a; // 39
88        $src += ((0x39 - $src) >> 8) & 39;
89
90        return \pack('C', $src);
91    }
92
93    /**
94     * Uses bitwise operators instead of table-lookups to turn 8-bit integers
95     * into 5-bit integers.
96     *
97     * Uppercase variant.
98     *
99     * @param int $src
100     * @return string
101     */
102    protected static function encode5BitsUpper(int $src): string
103    {
104        $src += 0x30;
105
106        // if ($src > 0x39) $src += 0x41 - 0x3a; // 7
107        $src += ((0x39 - $src) >> 8) & 7;
108
109        return \pack('C', $src);
110    }
111}