41 lines
1.1 KiB
C++
41 lines
1.1 KiB
C++
#pragma once
|
|
// used: [stl] uint64_t
|
|
#include <cstdint>
|
|
|
|
// used :CRT::StringLength
|
|
#include "crt.h"
|
|
|
|
using FNV1A_t = std::uint64_t;
|
|
|
|
/*
|
|
* 64-BIT FNV1A HASH
|
|
*/
|
|
namespace FNV1A
|
|
{
|
|
/* @section: [internal] constants */
|
|
constexpr FNV1A_t ullBasis = 0xCBF29CE484222325ULL;
|
|
constexpr FNV1A_t ullPrime = 0x100000001B3ULL;
|
|
|
|
/* @section: get */
|
|
/// @param[in] szString string for which you want to generate a hash
|
|
/// @param[in] uKey key of hash generation
|
|
/// @returns: calculated at compile-time hash of given string
|
|
consteval FNV1A_t HashConst(const char* szString, const FNV1A_t uKey = ullBasis) noexcept
|
|
{
|
|
return (szString[0] == '\0') ? uKey : HashConst(&szString[1], (uKey ^ static_cast<FNV1A_t>(szString[0])) * ullPrime);
|
|
}
|
|
|
|
/// @param[in] szString string for which you want to generate a hash
|
|
/// @param[in] uKey key of hash generation
|
|
/// @returns: calculated at run-time hash of given string
|
|
inline FNV1A_t Hash(const char* szString, FNV1A_t uKey = ullBasis) noexcept
|
|
{
|
|
const std::size_t nLength = CRT::StringLength(szString);
|
|
|
|
for (std::size_t i = 0U; i < nLength; ++i)
|
|
uKey = (uKey ^ szString[i]) * ullPrime;
|
|
|
|
return uKey;
|
|
}
|
|
}
|