void Data_Init(DataFile * df)
{
// Everything is NULL
- df->filename = NULL;
+ memset(df, 0, sizeof(DataFile));
pthread_mutex_init(&(df->mutex), NULL);
- df->file = NULL;
}
/**
switch (format)
{
case JSON:
- fmt_string = "[%f,%f]";
+ fmt_string = "[%.9f,%f]";
separator = ',';
// For JSON we need an opening bracket
FCGI_PrintRaw("[");
break;
case TSV:
- fmt_string = "%f\t%f";
+ fmt_string = "%.9f\t%f";
separator = '\n';
break;
}
}
return JSON;
}
+
+/**
+ * Binary search for index of a double in an array
+ * @param value - The value
+ * @param x - The array
+ * @param size - Sizeof the array
+ */
+int FindClosest(double value, double x[], int size)
+{
+ int upper = size-1;
+ int lower = 0;
+ int index = 0;
+ while (upper - lower > 1)
+ {
+ index = lower + ((upper - lower)/2);
+ double look = x[index];
+ if (look > value)
+ upper = index;
+ else if (look < value)
+ lower = index;
+ else
+ return index;
+ }
+
+ if (x[index] > value && index > 0)
+ --index;
+ return index;
+
+}
+
+/**
+ * Get calibrated value by interpolation in array y
+ * @param value - Raw measured value
+ * @param x - x values (raw values) of the data
+ * @param y - calibrated values
+ * @param size - Number of values in the arrays
+ * @returns interpolated calibrated value
+ */
+double Data_Calibrate(double value, double x[], double y[], int size)
+{
+ int i = FindClosest(value, x, size);
+ if (i >= size-1)
+ {
+ i = size-2;
+ }
+ double dist = (value - x[i])/(x[i+1] - x[i]);
+ return y[i] + dist*(y[i+1]-y[i]);
+}