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This commit is contained in:
Timur A. Fatkhullin
2026-09-18 09:48:11 +03:00
parent cf36c0186f
commit 09f4647ede
1 changed files with 14 additions and 13 deletions
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25
include/snipplib/utils/snplib_hash.h
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@@ -1,14 +1,15 @@
#pragma once #pragma once
#include "../concepts/snplib_concepts.h"
#include <iterator> #include <iterator>
#include "../concepts/snplib_concepts.h"
namespace snplib { namespace snplib
{
template <snplib_input_char_range_c R> template <snplib_input_char_range_c R>
static constexpr size_t FNV1aHash(const R& r) static constexpr size_t hash_FNV1a(const R& r)
{ {
static_assert(sizeof(size_t) == 8 || sizeof(size_t) == 4, "ONLY FOR 32 or 64-bit size_t!!!"); static_assert(sizeof(size_t) == 8 || sizeof(size_t) == 4, "The ONLY 32 or 64-bit std::size_t are supported!!!");
size_t hash = 0, prime = 0; size_t hash = 0, prime = 0;
if constexpr (sizeof(size_t) == 8) { // 64-bit if constexpr (sizeof(size_t) == 8) { // 64-bit
@@ -27,10 +28,10 @@ static constexpr size_t FNV1aHash(const R& r)
return hash; return hash;
} }
static constexpr size_t FNV1aHash(std::forward_iterator auto begin, std::sentinel_for<decltype(begin)> auto end) static constexpr size_t hash_FNV1a(std::forward_iterator auto begin, std::sentinel_for<decltype(begin)> auto end)
requires std::same_as<std::remove_cv_t<std::iter_value_t<decltype(begin)>>, char> requires std::same_as<std::remove_cv_t<std::iter_value_t<decltype(begin)>>, char>
{ {
static_assert(sizeof(size_t) == 8 || sizeof(size_t) == 4, "ONLY FOR 32 or 64-bit size_t!!!"); static_assert(sizeof(size_t) == 8 || sizeof(size_t) == 4, "The ONLY 32 or 64-bit std::size_t are supported!!!");
size_t hash = 0, prime = 0; size_t hash = 0, prime = 0;
if constexpr (sizeof(size_t) == 8) { // 64-bit if constexpr (sizeof(size_t) == 8) { // 64-bit
@@ -51,10 +52,11 @@ static constexpr size_t FNV1aHash(std::forward_iterator auto begin, std::sentine
// Boost implementation of hash combining // Boost implementation of hash combining
template <snplib_hashable_c T, snplib_hashable_c ...Ts> template <snplib_hashable_c T, snplib_hashable_c... Ts>
static constexpr void snplib_hash_combine(std::size_t& seed, const T& v, Ts&& ... vs) { static constexpr void snplib_hash_combine(std::size_t& seed, const T& v, Ts&&... vs)
{
static constexpr auto digits = std::numeric_limits<std::size_t>::digits; static constexpr auto digits = std::numeric_limits<std::size_t>::digits;
static_assert(digits == 64 || digits == 32, "Unsupported 'size_t' type size!"); static_assert(digits == 64 || digits == 32, "The ONLY 32 or 64-bit std::size_t are supported!!!");
if constexpr (digits == 64) { if constexpr (digits == 64) {
std::size_t x = seed + 0x9e3779b9 + std::hash<T>()(v); std::size_t x = seed + 0x9e3779b9 + std::hash<T>()(v);
@@ -65,8 +67,7 @@ static constexpr void snplib_hash_combine(std::size_t& seed, const T& v, Ts&& ..
x *= m; x *= m;
x ^= x >> 28; x ^= x >> 28;
seed = x; seed = x;
} } else { // 32-bits
else { // 32-bits
std::size_t x = seed + 0x9e3779b9 + std::hash<T>()(v); std::size_t x = seed + 0x9e3779b9 + std::hash<T>()(v);
const std::size_t m1 = 0x21f0aaad; const std::size_t m1 = 0x21f0aaad;
const std::size_t m2 = 0x735a2d97; const std::size_t m2 = 0x735a2d97;
@@ -83,4 +84,4 @@ static constexpr void snplib_hash_combine(std::size_t& seed, const T& v, Ts&& ..
} }
} }
} // end of snplib namespace } // namespace snplib