mirror of https://github.com/nostar/urfd.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
77 lines
2.1 KiB
77 lines
2.1 KiB
/*
|
|
* Library: libcrc
|
|
* Git: https://github.com/lammertb/libcrc
|
|
* Author: Lammert Bies
|
|
*
|
|
* This file is licensed under the MIT License as stated below
|
|
*
|
|
* Copyright (c) 1999-2016 Lammert Bies
|
|
* Copyright (c) 2020 Thomas A. Early, N7TAE
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in all
|
|
* copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
* SOFTWARE.
|
|
*
|
|
* Description
|
|
* -----------
|
|
* The source file contains routines which calculate the CCITT CRC
|
|
* values for an incoming byte string.
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
#include "M17CRC.h"
|
|
|
|
#define CRC_POLY_16 0x5935u
|
|
#define CRC_START_16 0xFFFFu
|
|
|
|
CM17CRC::CM17CRC()
|
|
{
|
|
for (uint16_t i=0; i<256; i++)
|
|
{
|
|
uint16_t crc = 0;
|
|
uint16_t c = i << 8;
|
|
|
|
for (uint16_t j=0; j<8; j++)
|
|
{
|
|
if ( (crc ^ c) & 0x8000 )
|
|
crc = ( crc << 1 ) ^ CRC_POLY_16;
|
|
else
|
|
crc = crc << 1;
|
|
|
|
c = c << 1;
|
|
}
|
|
crc_tab16[i] = crc;
|
|
}
|
|
}
|
|
|
|
uint16_t CM17CRC::CalcCRC( const uint8_t *input_str, size_t num_bytes ) const
|
|
{
|
|
uint16_t crc = CRC_START_16;
|
|
|
|
if ( input_str )
|
|
for (size_t a=0; a<num_bytes; a++)
|
|
{
|
|
crc = (crc << 8) ^ crc_tab16[ ((crc >> 8) ^ uint16_t(input_str[a])) & 0x00FF ];
|
|
}
|
|
|
|
return crc;
|
|
}
|