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setting up structure

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happyZYM
2024-05-21 06:35:55 +00:00
parent 735b0cb966
commit 5ae88e3312
10 changed files with 274 additions and 9 deletions
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59
src/include/utils.h Normal file
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#ifndef UTILS_H
#define UTILS_H
#include <cstdint>
#include <string>
#include <string_view>
typedef uint64_t hash_t;
inline hash_t SplitMix64Hash(const std::string &str) noexcept {
// constexpr static char salt1[10] = "mL;]-=eT";
// constexpr static char salt2[10] = "9B<mF_me";
constexpr static char inner_salt[17] = "si9aW@zl#2$3%4^!";
/* Reference: http://xorshift.di.unimi.it/splitmix64.c */
// str = salt1 + str + salt2;
hash_t ret = 0;
int i = 0;
for (; i + 8 <= str.length(); i += 8) {
ret ^= *reinterpret_cast<const hash_t *>(str.c_str() + i);
ret ^= *reinterpret_cast<const hash_t *>(inner_salt + (i & 15));
ret += 0x9e3779b97f4a7c15;
ret = (ret ^ (ret >> 30)) * 0xbf58476d1ce4e5b9;
ret = (ret ^ (ret >> 27)) * 0x94d049bb133111eb;
ret ^= ret >> 31;
}
for (; i < str.length(); ++i) {
ret ^= str[i];
ret ^= inner_salt[i & 15];
ret += 0x9e3779b97f4a7c15;
ret = (ret ^ (ret >> 30)) * 0xbf58476d1ce4e5b9;
ret = (ret ^ (ret >> 27)) * 0x94d049bb133111eb;
ret ^= ret >> 31;
}
return ret;
}
inline hash_t SplitMix64Hash(const std::string_view &str) noexcept {
// constexpr static char salt1[10] = "mL;]-=eT";
// constexpr static char salt2[10] = "9B<mF_me";
constexpr static char inner_salt[17] = "si9aW@zl#2$3%4^!";
/* Reference: http://xorshift.di.unimi.it/splitmix64.c */
// str = salt1 + str + salt2;
hash_t ret = 0;
int i = 0;
for (; i + 8 <= str.length(); i += 8) {
ret ^= *reinterpret_cast<const hash_t *>(str.data() + i);
ret ^= *reinterpret_cast<const hash_t *>(inner_salt + (i & 15));
ret += 0x9e3779b97f4a7c15;
ret = (ret ^ (ret >> 30)) * 0xbf58476d1ce4e5b9;
ret = (ret ^ (ret >> 27)) * 0x94d049bb133111eb;
ret ^= ret >> 31;
}
for (; i < str.length(); ++i) {
ret ^= str[i];
ret ^= inner_salt[i & 15];
ret += 0x9e3779b97f4a7c15;
ret = (ret ^ (ret >> 30)) * 0xbf58476d1ce4e5b9;
ret = (ret ^ (ret >> 27)) * 0x94d049bb133111eb;
ret ^= ret >> 31;
}
return ret;
}
#endif