rwwattson.c

/*  openwattson  - rwwattson.c library functions
 *  This is a library of functions common to Linux and Windows
 *  
 *  Version 0.1
 *  
 *  Control Wattson power meter
 *  
 *  Copyright 2010, Kary Främling, Jan Nyman
 *  This program is published under the GNU General Public license
 */

#include "rwwattson.h"

#include <strings.h>    //bzero()

/********************************************************************/
/* get_current_power_with_retry
 * Return current power reading. Retry a maximum of MAXRETRIES times
 * if an error occurs. Negative value is returned in case of error, 
 * greater than or equal to zero if successful.  
 * 
 * Input: Handle to Wattson
 *
 * Returns: Current power consumption
 *
 ********************************************************************/
int get_current_power_with_retry(WATTSON wattson)
{
	int power;
	int i;

	for ( i=0 ; i<MAXRETRIES ; i++ ) {
		power = get_current_power(wattson);
		if ( power >= 0 )
			break;
		mySleep(500000); // Give enough time for recovering
	}

	return power;
}

/********************************************************************/
/* get_current_generated_power_with_retry
 * Return current generated power reading. Retry a maximum of MAXRETRIES times
 * if an error occurs. Negative value is returned in case of error, 
 * greater than or equal to zero if successful.  
 * 
 * Input: Handle to Wattson
 *
 * Returns: Current generated power consumption
 *
 ********************************************************************/
int get_current_generated_power_with_retry(WATTSON wattson)
{
        int power;
        int i;

        for ( i=0 ; i<MAXRETRIES ; i++ ) {
                power = get_current_generated_power(wattson);
                if ( power >= 0 )
                        break;
                mySleep(500000); // Give enough time for recovering
        }

        return power;
}

/********************************************************************/


/********************************************************************/
/* get_current_power
 * Return current power reading. Negative value is returned in case of error, 
 * greater than or equal to zero if successful. 
 * This error handling is needed because sometimes Wattson returns 
 * negative values od some other error. This is probably due to some
 * "misuse" of the protocol due to our restricted knowledge about it. 
 * 
 * Input: Handle to Wattson
 *
 * Returns: Current power consumption
 *
 ********************************************************************/
int get_current_power(WATTSON wattson)
{
	char cmd[] = "nowp";
	//char cmd[] = "nowA00009 00\n";
	char result[REPLY_BUF_SIZE];
	unsigned int power = 0;

	tcflush(wattson, TCIOFLUSH); // Flush everything just in case

	if (writeport(wattson, cmd) <= 0)
		return(-1);

	mySleep(500000); // Give enough time for replying
    bzero(result, REPLY_BUF_SIZE);  // Clear the buffer before readport

 	if (readport(wattson, result) <= 0)
		return(-2);
	if ( result[0] == 'p' ) {		
		sscanf(result+1, "%x", &power);
	}
	else {
		return(-3); // Error in power value
	}

	return power;
}

/********************************************************************/
/* get_current_generated_power
 * Return current generated power reading. 
 * 
 * Input: Handle to Wattson
 *
 * Returns: Current generated power
 *
 ********************************************************************/
int get_current_generated_power(WATTSON wattson)
{
        char cmd[] = "noww";
        //char cmd[] = "nowA00009 00\n";
        char result[REPLY_BUF_SIZE];
        unsigned int power = 0;

        tcflush(wattson, TCIOFLUSH); // Flush everything just in case

        if (writeport(wattson, cmd) <= 0)
                return(-1);

        mySleep(500000); // Give enough time for replying
    bzero(result, REPLY_BUF_SIZE);  // Clear the buffer before readport

        if (readport(wattson, result) < 0)
                return(-2);
        if ( result[0] == 'w' ) {
                 sscanf(result+1, "%x", &power);
        }
         else {
                return(-3); // Error in power value
        }

        return power;
}


/********************************************************************
 * get_configuration()
 *
 * read setup parameters from openwattson.conf
 * It searches in this sequence:
 * 1. Path to config file including filename given as parameter
 * 2. ./openwattson.conf
 * 3. /usr/local/etc/openwattson.conf
 * 4. /etc/openwattson.conf
 *
 * See file openwattson.conf-dist for the format and option names/values
 *
 * input:    config file name with full path - pointer to string
 *
 * output:   struct config populated with valid settings either
 *           from config file or defaults
 *
 * returns:  0 = OK
 *          -1 = no config file or file open error
 *
 ********************************************************************/
int get_configuration(struct config_type *config, char *path)
{
	FILE *fptr;
	char inputline[1000] = "";
	char token[100] = "";
	char val[100] = "";
	char val2[100] = "";

	// First we set everything to defaults - faster than many if statements
	strcpy(config->serial_device_name, DEFAULT_SERIAL_DEVICE);  // Name of serial device

	// open the config file

	fptr = NULL;
	if (path != NULL)
		fptr = fopen(path, "r");   //first try the parameter given
	if (fptr == NULL)                  //then try default search
	{
		if ((fptr = fopen("openwattson.conf", "r")) == NULL)
		{
			if ((fptr = fopen("/usr/local/etc/openwattson.conf", "r")) == NULL)
			{
				if ((fptr = fopen("/etc/openwattson.conf", "r")) == NULL)
				{
					//Give up and use defaults
					return(-1);
				}
			}
		}
	}

	while (fscanf(fptr, "%[^\n]\n", inputline) != EOF)
	{
		sscanf(inputline, "%[^= \t]%*[ \t=]%s%*[, \t]%s%*[^\n]", token, val, val2);

		if (token[0] == '#')	// comment
			continue;

		if ((strcmp(token,"SERIAL_DEVICE")==0) && (strlen(val) != 0))
		{
			strcpy(config->serial_device_name,val);
			continue;
		}		
	}
	return (0);
}


/********************************************************************
 * initialize resets Wattson to cold start (rewind and start over)
 * 
 * Input:   device number of the already open serial port
 *           
 * Returns: 0 if fail, 1 if success
 *
 ********************************************************************/
int initialize(WATTSON wattson)
{
	return 1;
}