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Merge branch 'branchless'
Chaos Ci / test (push) Successful in 3m3s
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Chaos Ci / benchmark (push) Successful in 1m49s
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hashlag
2026-08-03 02:26:39 +03:00
parent 2323020714 d2c5cf891d
commit cd4e4b9cfc
2 changed files with 93 additions and 76 deletions
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Chaos/Padding/PadderPkcs7.hpp
+7 -76
View File
@@ -1,14 +1,13 @@
#ifndef CHAOS_PADDING_PADDERPKCS7_HPP
#define CHAOS_PADDING_PADDERPKCS7_HPP
#include <climits>
#include <cstddef>
#include <cstdint>
#include <iterator>
#include <limits>
#include <type_traits>
#include "Padding/Padder.hpp"
#include "Service/Branchless.hpp"
#include "Service/ChaosException.hpp"
namespace Chaos::Padding
@@ -51,7 +50,7 @@ public:
}
const uint8_t padSize = *std::prev(end);
uint8_t isOkay = ~BlIsZero<uint8_t>(padSize);
uint8_t isOkay = ~Branchless::IsZero<uint8_t>(padSize);
size_t suffixSize = 0;
InputIt it = end;
@@ -60,89 +59,21 @@ public:
--it;
++suffixSize;
isOkay &= (BlEq<uint8_t>(*it, padSize) |
BlGt<uint8_t, size_t>(suffixSize, padSize));
isOkay &= (Branchless::Eq<uint8_t>(*it, padSize) |
Branchless::Gt<uint8_t, size_t>(suffixSize, padSize));
}
isOkay &= BlGe<uint8_t, size_t>(suffixSize, padSize);
isOkay &= Branchless::Ge<uint8_t, size_t>(suffixSize, padSize);
return
{
.IsOkay_ = static_cast<bool>(isOkay),
.PadSize_ = BlSel<uint8_t>(isOkay, padSize, 0)
.PadSize_ = Branchless::Sel<uint8_t>(isOkay, padSize, 0)
};
}
private:
template<typename OutUInt, typename InUInt>
static constexpr OutUInt BlMsb(InUInt in) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
constexpr uint8_t shift = (sizeof(InUInt) * CHAR_BIT) - 1;
return static_cast<OutUInt>(0) - (in >> shift);
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt BlLt(InUInt lhs, InUInt rhs) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
static_assert(sizeof(InUInt) <= sizeof(uint64_t));
const uint64_t lhsEx = lhs;
const uint64_t rhsEx = rhs;
return BlMsb<OutUInt>(lhsEx ^ ((lhsEx ^ rhsEx) | ((lhsEx - rhsEx) ^ lhsEx)));
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt BlIsZero(InUInt in) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
static_assert(sizeof(InUInt) <= sizeof(uint64_t));
const uint64_t inEx = in;
return BlMsb<OutUInt>(~inEx & (inEx - 1U));
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt BlEq(InUInt lhs, InUInt rhs) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
return BlIsZero<OutUInt, InUInt>(lhs ^ rhs);
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt BlGe(InUInt lhs, InUInt rhs) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
return ~BlLt<OutUInt>(lhs, rhs);
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt BlGt(InUInt lhs, InUInt rhs) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
return BlLt<OutUInt>(rhs, lhs);
}
template<typename UInt>
static constexpr UInt BlSel(UInt mask, UInt onTrue, UInt onFalse) noexcept
{
static_assert(std::is_unsigned_v<UInt>);
return (mask & onTrue) | (~mask & onFalse);
}
using Branchless = Service::Branchless;
};
} // namespace Chaos::Padding
Chaos/Service/Branchless.hpp
+86
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@@ -0,0 +1,86 @@
#ifndef CHAOS_SERVICE_BRANCHLESS_HPP
#define CHAOS_SERVICE_BRANCHLESS_HPP
#include <type_traits>
#include <climits>
#include <cstdint>
namespace Chaos::Service
{
struct Branchless
{
template<typename OutUInt, typename InUInt>
static constexpr OutUInt Msb(InUInt in) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
constexpr uint8_t shift = (sizeof(InUInt) * CHAR_BIT) - 1;
return static_cast<OutUInt>(0) - (in >> shift);
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt Lt(InUInt lhs, InUInt rhs) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
static_assert(sizeof(InUInt) <= sizeof(uint64_t));
const uint64_t lhsEx = lhs;
const uint64_t rhsEx = rhs;
return Msb<OutUInt>(lhsEx ^ ((lhsEx ^ rhsEx) | ((lhsEx - rhsEx) ^ lhsEx)));
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt IsZero(InUInt in) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
static_assert(sizeof(InUInt) <= sizeof(uint64_t));
const uint64_t inEx = in;
return Msb<OutUInt>(~inEx & (inEx - 1U));
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt Eq(InUInt lhs, InUInt rhs) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
return IsZero<OutUInt, InUInt>(lhs ^ rhs);
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt Ge(InUInt lhs, InUInt rhs) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
return ~Lt<OutUInt>(lhs, rhs);
}
template<typename OutUInt, typename InUInt>
static constexpr OutUInt Gt(InUInt lhs, InUInt rhs) noexcept
{
static_assert(std::is_unsigned_v<OutUInt> &&
std::is_unsigned_v<InUInt>);
return Lt<OutUInt>(rhs, lhs);
}
template<typename UInt>
static constexpr UInt Sel(UInt mask, UInt onTrue, UInt onFalse) noexcept
{
static_assert(std::is_unsigned_v<UInt>);
return (mask & onTrue) | (~mask & onFalse);
}
};
} // namespace Chaos::Service
#endif // CHAOS_SERVICE_BRANCHLESS_HPP