ns_crc.c

00001 /*
00002  * Copyright (c) 2015, 2017, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 #include "ns_crc.h"
00018 
00019 //#define CRC_TEST
00020 
00021 #define POLYNOMIAL_CRC15_CCIT 0x1021
00022 #define POLYNOMIAL_CRC15_ANSI 0x8005
00023 
00024 uint16_t crc16_ansi(uint8_t *message, int nBytes) {
00025     return crc16_calc(message, nBytes, POLYNOMIAL_CRC15_ANSI);
00026 }
00027 uint16_t crc16_ccitt(uint8_t *message, int nBytes) {
00028     return crc16_calc(message, nBytes, POLYNOMIAL_CRC15_CCIT);
00029 }
00030 
00031 uint16_t crc16_calc(uint8_t* data, uint16_t data_length, uint16_t polynomial)
00032 {
00033   int crc = 0;
00034   int i, bit;
00035   for( i=0; i<data_length; i++ )
00036   {
00037     crc ^= (int)data[i] << 8;
00038     for (bit = 0; bit < 8; bit++)
00039     {
00040       if ( crc & 0x8000 ) {
00041         crc = (crc << 1) ^ polynomial;
00042       } else {
00043         crc <<= 1;
00044       }
00045     }
00046   }
00047   return crc&0xffff;
00048 }
00049 
00050 
00051 
00052 #ifdef CRC_TEST //unity test
00053 #include <stdio.h>
00054 #include <string.h>
00055 //#include "unity.h"
00056 
00057 #ifndef TEST_ASSERT_EQUAL_INT
00058 #define TEST_ASSERT_EQUAL_INT(a,b, s) do{ if(a!=b){printf("%s: 0x%04x != 0x%04x - FAIL\n", s, a, b);} else printf("%s: 0x%04x == 0x%04x - PASS\n", s,a,b);}while(0)
00059 #endif
00060 
00061 char data[] = "arm";
00062 /* Unity test code starts */
00063 void setUp(void)
00064 {
00065 }
00066 
00067 void tearDown(void)
00068 {
00069 }
00070 
00071 void test_param_crc16_ansi(void)
00072 {
00073     uint16_t crc = crc16_ibm(data, strlen(data));
00074     TEST_ASSERT_EQUAL_INT(crc, 0x2406, "CRC16-ansi");
00075 }
00076 void test_param_crc16_ccitt(void)
00077 {
00078     uint16_t crc = crc16_ccitt(data, strlen(data));
00079     TEST_ASSERT_EQUAL_INT(crc, 0x7F6B, "CRC16-CCIT");
00080 }
00081 
00082 void main(void)
00083 {
00084     test_param_crc16_ansi();
00085     test_param_crc16_ccitt();
00086 }
00087 
00088 #endif