ladybird/AK/Traits.h
kleines Filmröllchen 9a026fc8d5 AK: Implement SipHash as the default hash algorithm for most use cases
SipHash is highly HashDoS-resistent, initialized with a random seed at
startup (i.e. non-deterministic) and usable for security-critical use
cases with large enough parameters. We just use it because it's
reasonably secure with parameters 1-3 while having excellent properties
and not being significantly slower than before.
2023-10-01 11:06:36 +03:30

81 lines
2.5 KiB
C++

/*
* Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/BitCast.h>
#include <AK/Concepts.h>
#include <AK/Forward.h>
#include <AK/HashFunctions.h>
#include <AK/SipHash.h>
#include <AK/StringHash.h>
namespace AK {
template<typename T>
struct GenericTraits {
using PeekType = T&;
using ConstPeekType = T const&;
static constexpr bool is_trivial() { return false; }
static constexpr bool is_trivially_serializable() { return false; }
static constexpr bool equals(T const& a, T const& b) { return a == b; }
template<Concepts::HashCompatible<T> U>
static bool equals(T const& self, U const& other) { return self == other; }
};
template<typename T>
struct Traits : public GenericTraits<T> {
};
template<Integral T>
struct Traits<T> : public GenericTraits<T> {
static constexpr bool is_trivial() { return true; }
static constexpr bool is_trivially_serializable() { return true; }
static unsigned hash(T value)
{
return standard_sip_hash(static_cast<u64>(value));
}
};
#ifndef KERNEL
template<FloatingPoint T>
struct Traits<T> : public GenericTraits<T> {
static constexpr bool is_trivial() { return true; }
static constexpr bool is_trivially_serializable() { return true; }
static unsigned hash(T value)
{
return standard_sip_hash(bit_cast<u64>(static_cast<double>(value)));
}
};
#endif
template<typename T>
requires(IsPointer<T> && !Detail::IsPointerOfType<char, T>) struct Traits<T> : public GenericTraits<T> {
static unsigned hash(T p) { return standard_sip_hash(bit_cast<FlatPtr>(p)); }
static constexpr bool is_trivial() { return true; }
};
template<Enum T>
struct Traits<T> : public GenericTraits<T> {
static unsigned hash(T value) { return Traits<UnderlyingType<T>>::hash(to_underlying(value)); }
static constexpr bool is_trivial() { return Traits<UnderlyingType<T>>::is_trivial(); }
static constexpr bool is_trivially_serializable() { return Traits<UnderlyingType<T>>::is_trivially_serializable(); }
};
template<typename T>
requires(Detail::IsPointerOfType<char, T>) struct Traits<T> : public GenericTraits<T> {
static unsigned hash(T const value) { return string_hash(value, strlen(value)); }
static constexpr bool equals(T const a, T const b) { return strcmp(a, b); }
static constexpr bool is_trivial() { return true; }
};
}
#if USING_AK_GLOBALLY
using AK::GenericTraits;
using AK::Traits;
#endif