Hasher.hpp

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#pragma once
 
#include <cstdint>
#include <cstdio>
 
// NOLINTBEGIN
 
constexpr size_t constHasher(const char *s) { return (s && *s) ? (*s + 33 * constHasher(s + 1)) : 5381; }
 
template <size_t N> constexpr uint64_t constSeeder(const char (&entropy)[N], const uint64_t iv = 0)
{
    auto value{iv};
    for (size_t i{0}; i < N; i++)
    {
        // Xor 1st byte of seed with input byte
        value = (value & (unsigned(~0) << 8)) | ((value & 0xFF) ^ entropy[i]);
        // Rotl 1 byte
        value = value << 8 | value >> ((sizeof(value) * 8) - 8);
    }
    return value ^ iv;
}
 
// NOLINTEND