Utility functions for working with data streams
Example usage:
http://andy.dynamicbits.com/hdradio/
#include "mbed.h" #include "checksum.h" DigitalOut myled(LED1); template <int T> struct data{ uint8_t buf[T]; uint8_t checksum; }; data<12> all_ones = {{1,1,1,1,1,1,1,1,1,1,1,1}}; int main() { calculateChecksum( all_ones.buf, sizeof(all_ones) ); for(int i=0; i<sizeof(all_ones); i++) { printf("%02d: %d\n", i, *(all_ones.buf+i)); } printf("checksum test: %s\n", (result)?"passed":"failed"); while(1) { myled = 1; wait(0.2); myled = 0; wait(0.2); } }
checksum.h
- Committer:
- sam_grove
- Date:
- 2013-03-07
- Revision:
- 0:39b5762958a4
- Child:
- 1:ace4b3aef52b
File content as of revision 0:39b5762958a4:
/** * @file checksum.h * @brief Utility Function - Data integrity helpers * @author sam grove * @version 1.0 * * Copyright (c) 2013 * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /** Helpers for working data streams * * Example: * @code * #include "mbed.h" * #include "checksum.h" * * DigitalOut myled(LED1); * * template <int T> * struct data{ * uint8_t buf[T]; * uint8_t checksum; * }; * data<12> all_ones = {{1,1,1,1,1,1,1,1,1,1,1,1}}; * * int main() * { * calculateChecksum( all_ones.buf, sizeof(all_ones) ); * * for(int i=0; i<sizeof(all_ones); i++) * { * printf("%02d: %d\n", i, *(all_ones.buf+i)); * } * * printf("checksum test: %s\n", (result)?"passed":"failed"); * * while(1) * { * myled = 1; * wait(0.2); * myled = 0; * wait(0.2); * } * } * @endcode */ #ifndef CHECKSUM_H #define CHECKSUM_H #include <stdint.h> /** Calculate the checksum of a data stream * Assumes the checksum is in the last position, 8-bits and 0 - the sum of data * @param pkt - A pointer to the data * @param length - The amount of data that the checksum calculates * @returns true if the checksum is correct and false otherwise */ bool validateChecksum( uint8_t const *pkt, uint32_t const length ); /** Calculate and store the checksum into the last position of a data stream * * @param pkt - A pointer to the data * @param length - The amount of data that the checksum calculates */ void calculateChecksum( uint8_t *pkt, uint32_t const length ); #endif