File content as of revision 90:38dfa3f350aa:

/*buffer.cpp creates the circular buffer array and contains functions
responsible for pushing new data on to the queue and also pulling data
from it. It also contains the function to workout the moving average of
the 10 values stored within the circular buffer*/

#include "mbed.h"
#include "rtos.h"
#include "buffer.h"

//Creates a struct array, using the custom struct that holds the acceleration measurements.
AccelData circular_buffer_array[10];

int rear = 0;
int front = 0;
int32_t sumX;
int32_t sumY;
int32_t sumZ;
int32_t averageX;
int32_t averageY;
int32_t averageZ;

//Pushes data on to buffer using modulo operation.
void log_push(AccelData data) {

  rear = (rear + 1) % 10;

  if (rear == front) {
    front = (front + 1) % 10;
  }

  circular_buffer_array[rear] = data;

}

//Retrieves a single data struct using the argument to specify which.
AccelData log_get(int index)
{

  AccelData record;
  record = circular_buffer_array[(front + index) % 10];

  return record;

}

/*This function loops through the array and calculates the average.
It clears the sum totals each time around so that the average is
updated with the new value pushed on to the buffer, creating a 
moving average*/
void print_averages(){

    while(1){

    for (int i = 0; i < 10; i++) {

      AccelData entry = log_get(i);
      sumX += entry.x;
      sumY += entry.y;
      sumZ += entry.z;
      
      /*The two lines below can be uncomented to show the circular buffer working by
      outputting the contents of the buffer every time a peice of data is pushed on to it.
      This also makes it possible to verify the average is correct.*/
      
      //printf("LSM6DS0 [acc/mg]:      %6ld, %6ld, %6ld\r\n", entry.x, entry.y, entry.z);
      //printf("\r\n");
      
    }

    averageX = sumX / 10;
    averageY = sumY / 10;
    averageZ = sumZ / 10;
    printf("average [acc/mg]:      %6ld, %6ld, %6ld\r\n", averageX, averageY, averageZ);
    printf("\r\n");
    sumX = 0;
    sumY = 0;
    sumZ = 0;
}
}