jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2018-2021, the SerenityOS developers.
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#pragma once
8
9#include <AK/Types.h>
10
11namespace AK {
12
13constexpr u32 string_hash(char const* characters, size_t length, u32 seed = 0)
14{
15 u32 hash = seed;
16 for (size_t i = 0; i < length; ++i) {
17 hash += static_cast<u32>(characters[i]);
18 hash += (hash << 10);
19 hash ^= (hash >> 6);
20 }
21 hash += hash << 3;
22 hash ^= hash >> 11;
23 hash += hash << 15;
24 return hash;
25}
26
27constexpr u32 case_insensitive_string_hash(char const* characters, size_t length, u32 seed = 0)
28{
29 // AK/CharacterTypes.h cannot be included from here.
30 auto to_lowercase = [](char ch) -> u32 {
31 if (ch >= 'A' && ch <= 'Z')
32 return static_cast<u32>(ch) + 0x20;
33 return static_cast<u32>(ch);
34 };
35
36 u32 hash = seed;
37 for (size_t i = 0; i < length; ++i) {
38 hash += to_lowercase(characters[i]);
39 hash += (hash << 10);
40 hash ^= (hash >> 6);
41 }
42 hash += hash << 3;
43 hash ^= hash >> 11;
44 hash += hash << 15;
45 return hash;
46}
47
48}
49
50#if USING_AK_GLOBALLY
51using AK::string_hash;
52#endif