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9014af9ae7
Add crc8rohcincr() function to support byte-by-byte CRC8 calculation using the ROHC polynomial (0x07) without XOR inversions. This is useful for protocols that require incremental CRC accumulation, such as GSM 07.10 (CMUX), where the CRC must be computed as frames are parsed from circular buffers. Changes include: - New crc8rohcincr() function for single-byte incremental CRC - Function takes current CRC value and returns updated CRC - Uses same g_crc8_tab table as other ROHC functions - No XOR inversions applied for proper accumulation This allows protocols like CMUX to replace local CRC table implementations with standard libc CRC functions while maintaining correct incremental calculation behavior. Signed-off-by: Halysson <halysson1007@gmail.com>
100 lines
4.0 KiB
C
100 lines
4.0 KiB
C
/****************************************************************************
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* libs/libc/misc/lib_crc8rohc.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <sys/types.h>
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#include <stdint.h>
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#include <nuttx/crc8.h>
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const uint8_t g_crc8_tab[256] =
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{
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0x00, 0x91, 0xe3, 0x72, 0x07, 0x96, 0xe4, 0x75,
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0x0e, 0x9f, 0xed, 0x7c, 0x09, 0x98, 0xea, 0x7b,
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0x1c, 0x8d, 0xff, 0x6e, 0x1b, 0x8a, 0xf8, 0x69,
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0x12, 0x83, 0xf1, 0x60, 0x15, 0x84, 0xf6, 0x67,
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0x38, 0xa9, 0xdb, 0x4a, 0x3f, 0xae, 0xdc, 0x4d,
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0x36, 0xa7, 0xd5, 0x44, 0x31, 0xa0, 0xd2, 0x43,
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0x24, 0xb5, 0xc7, 0x56, 0x23, 0xb2, 0xc0, 0x51,
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0x2a, 0xbb, 0xc9, 0x58, 0x2d, 0xbc, 0xce, 0x5f,
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0x70, 0xe1, 0x93, 0x02, 0x77, 0xe6, 0x94, 0x05,
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0x7e, 0xef, 0x9d, 0x0c, 0x79, 0xe8, 0x9a, 0x0b,
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0x6c, 0xfd, 0x8f, 0x1e, 0x6b, 0xfa, 0x88, 0x19,
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0x62, 0xf3, 0x81, 0x10, 0x65, 0xf4, 0x86, 0x17,
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0x48, 0xd9, 0xab, 0x3a, 0x4f, 0xde, 0xac, 0x3d,
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0x46, 0xd7, 0xa5, 0x34, 0x41, 0xd0, 0xa2, 0x33,
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0x54, 0xc5, 0xb7, 0x26, 0x53, 0xc2, 0xb0, 0x21,
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0x5a, 0xcb, 0xb9, 0x28, 0x5d, 0xcc, 0xbe, 0x2f,
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0xe0, 0x71, 0x03, 0x92, 0xe7, 0x76, 0x04, 0x95,
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0xee, 0x7f, 0x0d, 0x9c, 0xe9, 0x78, 0x0a, 0x9b,
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0xfc, 0x6d, 0x1f, 0x8e, 0xfb, 0x6a, 0x18, 0x89,
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0xf2, 0x63, 0x11, 0x80, 0xf5, 0x64, 0x16, 0x87,
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0xd8, 0x49, 0x3b, 0xaa, 0xdf, 0x4e, 0x3c, 0xad,
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0xd6, 0x47, 0x35, 0xa4, 0xd1, 0x40, 0x32, 0xa3,
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0xc4, 0x55, 0x27, 0xb6, 0xc3, 0x52, 0x20, 0xb1,
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0xca, 0x5b, 0x29, 0xb8, 0xcd, 0x5c, 0x2e, 0xbf,
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0x90, 0x01, 0x73, 0xe2, 0x97, 0x06, 0x74, 0xe5,
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0x9e, 0x0f, 0x7d, 0xec, 0x99, 0x08, 0x7a, 0xeb,
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0x8c, 0x1d, 0x6f, 0xfe, 0x8b, 0x1a, 0x68, 0xf9,
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0x82, 0x13, 0x61, 0xf0, 0x85, 0x14, 0x66, 0xf7,
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0xa8, 0x39, 0x4b, 0xda, 0xaf, 0x3e, 0x4c, 0xdd,
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0xa6, 0x37, 0x45, 0xd4, 0xa1, 0x30, 0x42, 0xd3,
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0xb4, 0x25, 0x57, 0xc6, 0xb3, 0x22, 0x50, 0xc1,
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0xba, 0x2b, 0x59, 0xc8, 0xbd, 0x2c, 0x5e, 0xcf
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};
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: crc8rohcpart
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****************************************************************************/
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uint8_t crc8rohcpart(FAR const uint8_t *src, size_t len, uint8_t crc8val)
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{
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return crc8table(g_crc8_tab, src, len, crc8val);
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}
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/****************************************************************************
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* Name: crc8rohc
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****************************************************************************/
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uint8_t crc8rohc(FAR const uint8_t *src, size_t len)
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{
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return crc8rohcpart(src, len, 0xff);
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}
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/****************************************************************************
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* Name: crc8rohcincr
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****************************************************************************/
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uint8_t crc8rohcincr(uint8_t data_byte, uint8_t crc8val)
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{
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return g_crc8_tab[crc8val ^ data_byte];
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}
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