41 lines
1.2 KiB
Dart
41 lines
1.2 KiB
Dart
|
library hash;
|
||
|
|
|
||
|
|
/// Created by @Haoyi on 2021/7/7
|
||
|
|
|
||
|
|
/// Generates a hash code for multiple [objects].
|
||
|
|
int hashObjects(Iterable objects) => _finish(objects.fold(0, (h, i) => _combine(h, i.hashCode)));
|
||
|
|
|
||
|
|
/// Generates a hash code for two objects.
|
||
|
|
int hash2(a, b) => _finish(_combine(_combine(0, a.hashCode), b.hashCode));
|
||
|
|
|
||
|
|
/// Generates a hash code for three objects.
|
||
|
|
int hash3(a, b, c) => _finish(_combine(_combine(_combine(0, a.hashCode), b.hashCode), c.hashCode));
|
||
|
|
|
||
|
|
/// Generates a hash code for four objects.
|
||
|
|
int hash4(a, b, c, d) => _finish(
|
||
|
|
_combine(_combine(_combine(_combine(0, a.hashCode), b.hashCode), c.hashCode), d.hashCode));
|
||
|
|
|
||
|
|
int hashIntList(List<int> list) => _finish(list.fold(0x9E370001, (h, i) => _combine(h, i)));
|
||
|
|
|
||
|
|
// Jenkins hash functions
|
||
|
|
|
||
|
|
int _combine(int hash, int value) {
|
||
|
|
hash = 0x1fffffff & (hash + value);
|
||
|
|
hash = 0x1fffffff & (hash + ((0x0007ffff & hash) << 10));
|
||
|
|
return hash ^ (hash >> 6);
|
||
|
|
}
|
||
|
|
|
||
|
|
int _finish(int hash) {
|
||
|
|
hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
|
||
|
|
hash = hash ^ (hash >> 11);
|
||
|
|
return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
|
||
|
|
}
|
||
|
|
|
||
|
|
int hashCombine(int hash, int value) {
|
||
|
|
return _combine(hash, value);
|
||
|
|
}
|
||
|
|
|
||
|
|
int hashFinish(int hash) {
|
||
|
|
return _finish(hash);
|
||
|
|
}
|