Jonny Svärd | 5adf5a6 | 2022-02-09 16:42:10 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2022 Arm Limited. All rights reserved. |
| 3 | * |
| 4 | * SPDX-License-Identifier: Apache-2.0 |
| 5 | * |
| 6 | * Licensed under the Apache License, Version 2.0 (the License); you may |
| 7 | * not use this file except in compliance with the License. |
| 8 | * You may obtain a copy of the License at |
| 9 | * |
| 10 | * www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, software |
| 13 | * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
| 14 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | */ |
| 18 | |
| 19 | #include <cstddef> |
| 20 | #include <inttypes.h> |
| 21 | |
| 22 | namespace { |
| 23 | |
| 24 | class Crc { |
| 25 | public: |
| 26 | constexpr Crc() : table() { |
| 27 | uint32_t poly = 0xedb88320; |
| 28 | |
| 29 | for (uint32_t i = 0; i < 256; i++) { |
| 30 | uint32_t crc = i; |
| 31 | |
| 32 | for (int j = 0; j < 8; j++) { |
| 33 | if (crc & 1) { |
| 34 | crc = poly ^ (crc >> 1); |
| 35 | } else { |
| 36 | crc >>= 1; |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | table[i] = crc; |
| 41 | } |
| 42 | } |
| 43 | |
| 44 | uint32_t crc32(const void *data, const size_t length, uint32_t init = 0) const { |
| 45 | uint32_t crc = init ^ 0xffffffff; |
| 46 | |
| 47 | const uint8_t *v = static_cast<const uint8_t *>(data); |
| 48 | |
| 49 | for (size_t i = 0; i < length; i++) { |
| 50 | crc = table[(crc ^ v[i]) & 0xff] ^ (crc >> 8); |
| 51 | } |
| 52 | |
| 53 | return crc ^ 0xffffffff; |
| 54 | } |
| 55 | |
| 56 | private: |
| 57 | uint32_t table[256]; |
| 58 | }; |
| 59 | } // namespace |