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// Copyright 2022 The Abseil Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_CRC_INTERNAL_CRC_MEMCPY_H_
#define ABSL_CRC_INTERNAL_CRC_MEMCPY_H_
#include <cstddef>
#include <memory>
#include "absl/base/config.h"
#include "absl/crc/crc32c.h"
#include "absl/crc/internal/crc32_x86_arm_combined_simd.h"
// Defined if the class AcceleratedCrcMemcpyEngine exists.
// TODO(b/299127771): Consider relaxing the pclmul requirement once the other
// intrinsics are conditionally compiled without it.
#if defined(ABSL_CRC_INTERNAL_HAVE_X86_SIMD)
#define ABSL_INTERNAL_HAVE_X86_64_ACCELERATED_CRC_MEMCPY_ENGINE 1
#elif defined(ABSL_CRC_INTERNAL_HAVE_ARM_SIMD)
#define ABSL_INTERNAL_HAVE_ARM_ACCELERATED_CRC_MEMCPY_ENGINE 1
#endif
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace crc_internal {
class CrcMemcpyEngine {
public:
virtual ~CrcMemcpyEngine() = default;
virtual crc32c_t Compute(void* __restrict dst, const void* __restrict src,
std::size_t length, crc32c_t initial_crc) const = 0;
protected:
CrcMemcpyEngine() = default;
};
class CrcMemcpy {
public:
static crc32c_t CrcAndCopy(void* __restrict dst, const void* __restrict src,
std::size_t length,
crc32c_t initial_crc = crc32c_t{0},
bool non_temporal = false) {
static const ArchSpecificEngines engines = GetArchSpecificEngines();
auto* engine = non_temporal ? engines.non_temporal : engines.temporal;
return engine->Compute(dst, src, length, initial_crc);
}
// For testing only: get an architecture-specific engine for tests.
static std::unique_ptr<CrcMemcpyEngine> GetTestEngine(int vector,
int integer);
private:
struct ArchSpecificEngines {
CrcMemcpyEngine* temporal;
CrcMemcpyEngine* non_temporal;
};
static ArchSpecificEngines GetArchSpecificEngines();
};
// Fallback CRC-memcpy engine.
class FallbackCrcMemcpyEngine : public CrcMemcpyEngine {
public:
FallbackCrcMemcpyEngine() = default;
FallbackCrcMemcpyEngine(const FallbackCrcMemcpyEngine&) = delete;
FallbackCrcMemcpyEngine operator=(const FallbackCrcMemcpyEngine&) = delete;
crc32c_t Compute(void* __restrict dst, const void* __restrict src,
std::size_t length, crc32c_t initial_crc) const override;
};
// CRC Non-Temporal-Memcpy engine.
class CrcNonTemporalMemcpyEngine : public CrcMemcpyEngine {
public:
CrcNonTemporalMemcpyEngine() = default;
CrcNonTemporalMemcpyEngine(const CrcNonTemporalMemcpyEngine&) = delete;
CrcNonTemporalMemcpyEngine operator=(const CrcNonTemporalMemcpyEngine&) =
delete;
crc32c_t Compute(void* __restrict dst, const void* __restrict src,
std::size_t length, crc32c_t initial_crc) const override;
};
// CRC Non-Temporal-Memcpy AVX engine.
class CrcNonTemporalMemcpyAVXEngine : public CrcMemcpyEngine {
public:
CrcNonTemporalMemcpyAVXEngine() = default;
CrcNonTemporalMemcpyAVXEngine(const CrcNonTemporalMemcpyAVXEngine&) = delete;
CrcNonTemporalMemcpyAVXEngine operator=(
const CrcNonTemporalMemcpyAVXEngine&) = delete;
crc32c_t Compute(void* __restrict dst, const void* __restrict src,
std::size_t length, crc32c_t initial_crc) const override;
};
// Copy source to destination and return the CRC32C of the data copied. If an
// accelerated version is available, use the accelerated version, otherwise use
// the generic fallback version.
inline crc32c_t Crc32CAndCopy(void* __restrict dst, const void* __restrict src,
std::size_t length,
crc32c_t initial_crc = crc32c_t{0},
bool non_temporal = false) {
return CrcMemcpy::CrcAndCopy(dst, src, length, initial_crc, non_temporal);
}
} // namespace crc_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_CRC_INTERNAL_CRC_MEMCPY_H_