void initMeterItems(void);
unsigned long long getEpochTimeWithMs(void);

#define NUMBER_OF_METERS 10 /* the number of meters we use */

#define METER_INDEX_GAS 0 /* index of the gas meter data */


typedef struct
{
  portSHORT meterEnabled;  /* 0: item not used, 1: meter enabled */
  unsigned long long timeLastTick; /* when did the last tick occur? epoch time in seconds */
  unsigned long long timeBeforeLastTick; /* when did the tick before the last tick occur? epoch time in seconds */
  portLONG valueLastTick;   /* what value did we have at the last tick? */
  portLONG valueBeforeLastTick;   /* what value did we have at the tick before the last tick? */
} meterItem;

meterItem meterItems[NUMBER_OF_METERS]; /* the data for all the meters */