2 * Copyright 2017 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
19 #include <immintrin.h>
23 namespace folly { namespace detail {
26 * Compute a CRC-32C checksum of a buffer using a hardware-accelerated
29 * @note This function is exposed to support special cases where the
30 * calling code is absolutely certain it ought to invoke a hardware-
31 * accelerated CRC-32C implementation - unit tests, for example. For
32 * all other scenarios, please call crc32c() and let it pick an
33 * implementation based on the capabilities of the underlying CPU.
35 uint32_t crc32c_hw(const uint8_t* data, size_t nbytes,
36 uint32_t startingChecksum = ~0U);
39 * Check whether a hardware-accelerated CRC-32C implementation is
40 * supported on the current CPU.
42 bool crc32c_hw_supported();
45 * Compute a CRC-32C checksum of a buffer using a portable,
46 * software-only implementation.
48 * @note This function is exposed to support special cases where the
49 * calling code is absolutely certain it wants to use the software
50 * implementation instead of the hardware-accelerated code - unit
51 * tests, for example. For all other scenarios, please call crc32c()
52 * and let it pick an implementation based on the capabilities of
55 uint32_t crc32c_sw(const uint8_t* data, size_t nbytes,
56 uint32_t startingChecksum = ~0U);
59 * Compute a CRC-32 checksum of a buffer using a hardware-accelerated
62 * @note This function is exposed to support special cases where the
63 * calling code is absolutely certain it ought to invoke a hardware-
64 * accelerated CRC-32 implementation - unit tests, for example. For
65 * all other scenarios, please call crc32() and let it pick an
66 * implementation based on the capabilities of the underlying CPU.
69 crc32_hw(const uint8_t* data, size_t nbytes, uint32_t startingChecksum = ~0U);
72 crc32_hw_aligned(uint32_t remainder, const __m128i* p, size_t vec_count);
75 * Check whether a hardware-accelerated CRC-32 implementation is
76 * supported on the current CPU.
78 bool crc32_hw_supported();
81 * Compute a CRC-32 checksum of a buffer using a portable,
82 * software-only implementation.
84 * @note This function is exposed to support special cases where the
85 * calling code is absolutely certain it wants to use the software
86 * implementation instead of the hardware-accelerated code - unit
87 * tests, for example. For all other scenarios, please call crc32()
88 * and let it pick an implementation based on the capabilities of
92 crc32_sw(const uint8_t* data, size_t nbytes, uint32_t startingChecksum = ~0U);