xref: /aosp_15_r20/external/flac/oss-fuzz/fuzzing/datasource/id.hpp (revision 600f14f40d737144c998e2ec7a483122d3776fbc)
1 /* Copyright 2019 Guido Vranken
2  *
3  * Permission is hereby granted, free of charge, to any person obtaining
4  * a copy of this software and associated documentation files (the
5  * "Software"), to deal in the Software without restriction, including
6  * without limitation the rights to use, copy, modify, merge, publish,
7  * distribute, sublicense, and/or sell copies of the Software, and to
8  * permit persons to whom the Software is furnished to do so, subject
9  * to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be
12  * included in all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
18  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
19  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
20  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21  * SOFTWARE.
22  */
23 
24 #pragma once
25 
26 #include <stdio.h>
27 #include <stdint.h>
28 #include <utility>
29 #include <map>
30 
31 namespace fuzzing {
32 namespace datasource  {
33 
34 /* From: https://gist.github.com/underscorediscovery/81308642d0325fd386237cfa3b44785c */
hash_64_fnv1a(const void * key,const uint64_t len)35 inline uint64_t hash_64_fnv1a(const void* key, const uint64_t len) {
36 
37     const char* data = (char*)key;
38     uint64_t hash = 0xcbf29ce484222325;
39     uint64_t prime = 0x100000001b3;
40 
41     for(uint64_t i = 0; i < len; ++i) {
42         uint8_t value = data[i];
43         hash = hash ^ value;
44         hash *= prime;
45     }
46 
47     return hash;
48 
49 } //hash_64_fnv1a
50 
51 // FNV1a c++11 constexpr compile time hash functions, 32 and 64 bit
52 // str should be a null terminated string literal, value should be left out
53 // e.g hash_32_fnv1a_const("example")
54 // code license: public domain or equivalent
55 // post: https://notes.underscorediscovery.com/constexpr-fnv1a/
56 
57 constexpr uint32_t val_32_const = 0x811c9dc5;
58 constexpr uint32_t prime_32_const = 0x1000193;
59 constexpr uint64_t val_64_const = 0xcbf29ce484222325;
60 constexpr uint64_t prime_64_const = 0x100000001b3;
61 
62 
ID(const char * const str,const uint64_t value=val_64_const)63 inline constexpr uint64_t ID(const char* const str, const uint64_t value = val_64_const) noexcept {
64     auto ret = (str[0] == '\0') ? value : ID(&str[1], (value ^ uint64_t(str[0])) * prime_64_const);
65     return ret;
66 }
67 
IDPair(const char * const str,const uint64_t value=val_64_const)68 inline constexpr std::pair<const char*, uint64_t> IDPair(const char* const str, const uint64_t value = val_64_const) noexcept {
69     return {str, ID(str, value)};
70 }
71 
72 using IDMap = std::map<const char*, uint64_t>;
73 
74 } /* namespace datasource */
75 } /* namespace fuzzing */
76