Sam Grove / checksum

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@1:ace4b3aef52b, 2013-03-07 (annotated)

Committer:
sam_grove
Date:
Thu Mar 07 20:59:49 2013 +0000
Revision:
1:ace4b3aef52b
Parent:
0:39b5762958a4 
More documentation updates

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sam_grove 0:39b5762958a4 1 /**
sam_grove 0:39b5762958a4 2 * @file checksum.h
sam_grove 0:39b5762958a4 3 * @brief Utility Function - Data integrity helpers
sam_grove 0:39b5762958a4 4 * @author sam grove
sam_grove 0:39b5762958a4 5 * @version 1.0
sam_grove 0:39b5762958a4 6 *
sam_grove 0:39b5762958a4 7 * Copyright (c) 2013
sam_grove 0:39b5762958a4 8 *
sam_grove 0:39b5762958a4 9 * Licensed under the Apache License, Version 2.0 (the "License");
sam_grove 0:39b5762958a4 10 * you may not use this file except in compliance with the License.
sam_grove 0:39b5762958a4 11 * You may obtain a copy of the License at
sam_grove 0:39b5762958a4 12 *
sam_grove 0:39b5762958a4 13 * http://www.apache.org/licenses/LICENSE-2.0
sam_grove 0:39b5762958a4 14 *
sam_grove 0:39b5762958a4 15 * Unless required by applicable law or agreed to in writing, software
sam_grove 0:39b5762958a4 16 * distributed under the License is distributed on an "AS IS" BASIS,
sam_grove 0:39b5762958a4 17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
sam_grove 0:39b5762958a4 18 * See the License for the specific language governing permissions and
sam_grove 0:39b5762958a4 19 * limitations under the License.
sam_grove 0:39b5762958a4 20 */
sam_grove 0:39b5762958a4 21
sam_grove 1:ace4b3aef52b 22 #ifndef CHECKSUM_H
sam_grove 1:ace4b3aef52b 23 #define CHECKSUM_H
sam_grove 1:ace4b3aef52b 24
sam_grove 1:ace4b3aef52b 25 #include <stdint.h>
sam_grove 1:ace4b3aef52b 26
sam_grove 0:39b5762958a4 27 /** Helpers for working data streams
sam_grove 0:39b5762958a4 28 *
sam_grove 0:39b5762958a4 29 * Example:
sam_grove 0:39b5762958a4 30 * @code
sam_grove 0:39b5762958a4 31 * #include "mbed.h"
sam_grove 0:39b5762958a4 32 * #include "checksum.h"
sam_grove 0:39b5762958a4 33 *
sam_grove 0:39b5762958a4 34 * DigitalOut myled(LED1);
sam_grove 0:39b5762958a4 35 *
sam_grove 0:39b5762958a4 36 * template <int T>
sam_grove 0:39b5762958a4 37 * struct data{
sam_grove 0:39b5762958a4 38 * uint8_t buf[T];
sam_grove 0:39b5762958a4 39 * uint8_t checksum;
sam_grove 0:39b5762958a4 40 * };
sam_grove 0:39b5762958a4 41 * data<12> all_ones = {{1,1,1,1,1,1,1,1,1,1,1,1}};
sam_grove 0:39b5762958a4 42 *
sam_grove 0:39b5762958a4 43 * int main()
sam_grove 0:39b5762958a4 44 * {
sam_grove 0:39b5762958a4 45 * calculateChecksum( all_ones.buf, sizeof(all_ones) );
sam_grove 0:39b5762958a4 46 *
sam_grove 0:39b5762958a4 47 * for(int i=0; i<sizeof(all_ones); i++)
sam_grove 0:39b5762958a4 48 * {
sam_grove 0:39b5762958a4 49 * printf("%02d: %d\n", i, *(all_ones.buf+i));
sam_grove 0:39b5762958a4 50 * }
sam_grove 0:39b5762958a4 51 *
sam_grove 0:39b5762958a4 52 * printf("checksum test: %s\n", (result)?"passed":"failed");
sam_grove 0:39b5762958a4 53 *
sam_grove 0:39b5762958a4 54 * while(1)
sam_grove 0:39b5762958a4 55 * {
sam_grove 0:39b5762958a4 56 * myled = 1;
sam_grove 0:39b5762958a4 57 * wait(0.2);
sam_grove 0:39b5762958a4 58 * myled = 0;
sam_grove 0:39b5762958a4 59 * wait(0.2);
sam_grove 0:39b5762958a4 60 * }
sam_grove 0:39b5762958a4 61 * }
sam_grove 0:39b5762958a4 62 * @endcode
sam_grove 0:39b5762958a4 63 */
sam_grove 0:39b5762958a4 64
sam_grove 0:39b5762958a4 65 /** Calculate the checksum of a data stream
sam_grove 0:39b5762958a4 66 * Assumes the checksum is in the last position, 8-bits and 0 - the sum of data
sam_grove 0:39b5762958a4 67 * @param pkt - A pointer to the data
sam_grove 0:39b5762958a4 68 * @param length - The amount of data that the checksum calculates
sam_grove 0:39b5762958a4 69 * @returns true if the checksum is correct and false otherwise
sam_grove 0:39b5762958a4 70 */
sam_grove 0:39b5762958a4 71 bool validateChecksum( uint8_t const *pkt, uint32_t const length );
sam_grove 0:39b5762958a4 72
sam_grove 0:39b5762958a4 73 /** Calculate and store the checksum into the last position of a data stream
sam_grove 0:39b5762958a4 74 *
sam_grove 0:39b5762958a4 75 * @param pkt - A pointer to the data
sam_grove 0:39b5762958a4 76 * @param length - The amount of data that the checksum calculates
sam_grove 0:39b5762958a4 77 */
sam_grove 0:39b5762958a4 78 void calculateChecksum( uint8_t *pkt, uint32_t const length );
sam_grove 0:39b5762958a4 79
sam_grove 0:39b5762958a4 80 #endif