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64 lines
2.4 KiB
C
64 lines
2.4 KiB
C
/*
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* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2025 OpenMV, LLC.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef __OMV_CRC_H__
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#define __OMV_CRC_H__
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#include <stdint.h>
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#include <stddef.h>
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#include <stdbool.h>
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// 0xBAAD is ironically good - HD=5 up to 108 bits, HD=4 up to 7985 bits
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#define OMV_CRC_POLY (0xBAAD)
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#define OMV_CRC_INIT (0xFFFF)
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#define OMV_CRC_SIZE (16)
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typedef uint16_t omv_crc_t;
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// Initialize CRC hardware (if available)
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void omv_crc_init(void);
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// Start CRC calculation for buffer data
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omv_crc_t omv_crc_start(const void *buf, size_t size);
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// Update CRC with additional buffer data
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omv_crc_t omv_crc_update(omv_crc_t crc, const void *buf, size_t size);
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// Read CRC value from the last 2 bytes of buffer
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static inline omv_crc_t omv_crc_read(const void *buf, size_t size) {
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const uint8_t *crc_buf = (const uint8_t *)buf + size - 2;
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return *((omv_crc_t*) crc_buf);
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}
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// Calculate CRC and write it to the last 2 bytes of buffer
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static inline void omv_crc_write(void *buf, size_t size) {
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omv_crc_t crc = omv_crc_start(buf, size - 2);
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uint8_t *crc_buf = (uint8_t *)buf + size - 2;
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crc_buf[0] = crc & 0xFF;
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crc_buf[1] = (crc >> 8) & 0xFF;
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}
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// Calculate and check if CRC matches the one stored in buffer
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static inline bool omv_crc_check(const void *buf, size_t size) {
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return omv_crc_read(buf, size) == omv_crc_start(buf, size - 2);
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}
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#endif // __OMV_CRC_H__
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