Hasher.hpp File Reference

#include <cstdint>
#include <cstdio>

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Functions
constexpr size_t	constHasher (const char *s)
template<size_t N>
constexpr uint64_t	constSeeder (const char(&entropy)[N], const uint64_t iv=0)

Function Documentation

constHasher()

size_t constHasher ( const char * s )

constexpr

Calculates the compile-time hash value of a string.

Parameters

[in]

s

The input string. Must be null-terminated.

Returns

The hash value of the input string.

Definition at line 13 of file Hasher.hpp.

{ return (s && *s) ? (*s + 33 * constHasher(s + 1)) : 5381; }

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constSeeder()

template<size_t N>

uint64_t constSeeder ( const char(&) entropy[N], const uint64_t iv = 0 )

constexpr

Generates entropy using the input string and an initial value.

Parameters

[in]	entropy	The input string used for generating entropy.
[in]	iv	The initial value for the entropy generation.

Returns

The generated entropy value.

Definition at line 21 of file Hasher.hpp.

{
    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;
}