Sam Grove / checksum

Utility functions for working with data streams

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checksum.cpp File Reference
Functions

checksum.cpp File Reference

Utility Function - Data integrity helpers. More...

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Functions

bool validateChecksum (uint8_t const *pkt, uint32_t const length)
 Helpers for working data streams.
void calculateChecksum (uint8_t *pkt, uint32_t const length)
 Calculate and store the checksum into the last position of a data stream.

Detailed Description

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.

Definition in file checksum.cpp.

Function Documentation

void calculateChecksum ( uint8_t *  pkt,
uint32_t const   length 
)

Calculate and store the checksum into the last position of a data stream.

Parameters:
pkt- A pointer to the data
length- The amount of data that the checksum calculates

Definition at line 37 of file checksum.cpp.

bool validateChecksum ( uint8_t const *  pkt,
uint32_t const   length 
)

Helpers for working data streams.

Example: 

  #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);
      }
  }

Calculate the checksum of a data stream Assumes the checksum is in the last position, 8-bits and 0 - the sum of data

Parameters:
pkt- A pointer to the data
length- The amount of data that the checksum calculates
Returns:
true if the checksum is correct and false otherwise

Definition at line 24 of file checksum.cpp.

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