1 /*
2  * Copyright 2017 WebAssembly Community Group participants
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "src/hash-util.h"
18 
19 #include "config.h"
20 
21 namespace wabt {
22 
23 // Hash combiner from:
24 // http://stackoverflow.com/questions/4948780/magic-number-in-boosthash-combine
25 
HashCombine(hash_code seed,hash_code y)26 hash_code HashCombine(hash_code seed, hash_code y) {
27 #if SIZEOF_SIZE_T == 4
28   constexpr hash_code magic = 0x9e3779b9;
29 #elif SIZEOF_SIZE_T == 8
30   constexpr hash_code magic = 0x9e3779b97f4a7c16;
31 #else
32 #error "weird sizeof size_t"
33 #endif
34   seed ^= y + magic + (seed << 6) + (seed >> 2);
35   return seed;
36 }
37 
38 }  // namespace wabt
39