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40 lines
1.1 KiB
40 lines
1.1 KiB
/* |
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* Copyright (c) 2021 Workaround GmbH. |
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* |
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* SPDX-License-Identifier: Apache-2.0 |
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*/ |
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#include <zephyr/sys/crc.h> |
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/* crc table generated from polynomial 0x1EDC6F41UL (Castagnoli) */ |
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static const uint32_t crc32c_table[16] = { |
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0x00000000UL, 0x105EC76FUL, 0x20BD8EDEUL, 0x30E349B1UL, |
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0x417B1DBCUL, 0x5125DAD3UL, 0x61C69362UL, 0x7198540DUL, |
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0x82F63B78UL, 0x92A8FC17UL, 0xA24BB5A6UL, 0xB21572C9UL, |
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0xC38D26C4UL, 0xD3D3E1ABUL, 0xE330A81AUL, 0xF36E6F75UL |
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}; |
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/* This value needs to be XORed with the final crc value once crc for |
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* the entire stream is calculated. This is a requirement of crc32c algo. |
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*/ |
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#define CRC32C_XOR_OUT 0xFFFFFFFFUL |
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/* The crc32c algorithm requires the below value as Init value at the |
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* beginning of the stream. |
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*/ |
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#define CRC32C_INIT 0xFFFFFFFFUL |
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uint32_t crc32_c(uint32_t crc, const uint8_t *data, |
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size_t len, bool first_pkt, bool last_pkt) |
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{ |
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if (first_pkt) { |
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crc = CRC32C_INIT; |
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} |
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for (size_t i = 0; i < len; i++) { |
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crc = crc32c_table[(crc ^ data[i]) & 0x0F] ^ (crc >> 4); |
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crc = crc32c_table[(crc ^ ((uint32_t)data[i] >> 4)) & 0x0F] ^ (crc >> 4); |
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} |
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return last_pkt ? (crc ^ CRC32C_XOR_OUT) : crc; |
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}
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