Rflink.cpp

/*********************************************************************************
 * RFLink parser functions
   /*********************************************************************************/
#include "Rflink.h"

/**
 * Read RFLink packet (line terminated by \n) and
 * - extract message name / driver (eg: OregonV1) to MQTT_NAME
 * - extract ID of the sender (eg: ID=012345) to MQTT_ID
 * - create a JSON message with all encountered fields
 */
void readRfLinkPacket(char* line) {
        int i = 6; // ignore message type and line number
        int j = 0;
        bool nameHasEq = false;

        // check len and ignore bad packet (broken serial, etc.)
        if(strlen(line) < RFLINK_PACKET_MIN_SIZE) return;

        // get name : 3rd field (begins at char 6)
        while(line[i] != ';' && i < BUFFER_SIZE && j < MAX_DATA_LEN) {
                if      (line[i]==' ') MQTT_NAME[j] = '_';
                else if (line[i]=='=')  { nameHasEq = true; break; }
                else MQTT_NAME[j] = line[i];
                i++; j++;
        }

        // ends string correctly
        MQTT_NAME[j] = '\0';

        // if name contains "=", assumes that it's an rflink message, not an RF packet
        // thus we put a special name and ID=0, then parse to JSON
        if(nameHasEq==true) {
                Serial.println(F("name contains '=' !"));
                i = 6;
                strcpy_P(MQTT_NAME,PSTR("message"));
                MQTT_ID[0]='0'; MQTT_ID[1]='\0';
                readRfLinkFields(line, i);
                return;
        }

        if ( strcmp(MQTT_NAME,"STATUS") == 0){
          // Meldung STATUS
          MQTT_ID[0]='0'; MQTT_ID[1]='\0';
          i = 13;
          readRfLinkFields(line, i);
          return;
        }

        if (strncmp_P(MQTT_NAME,RFLINK_MQTT_NAME_NODO,12) == 0)
        {
          strcpy_P(MQTT_NAME,RFLINK_MQTT_NAME_NODO);
          MQTT_ID[0]='0'; MQTT_ID[1]='\0';
          strcpy(JSON,line+6);
          return;
        }

        // for debug and ACK messages, send them directly, no json convertion
        if(RfLinkIsStringInArray(MQTT_NAME,RFLINK_MQTT_NAMES_NO_JSON)) {
                Serial.println(F("Special name found => no JSON convertion"));
                MQTT_ID[0]='0'; MQTT_ID[1]='\0';
                j=0;
                i++; // Skip ;
                while(line[i] != '\n' && i < BUFFER_SIZE && j < BUFFER_SIZE) {
                        JSON[j++] = line[i++];
                }
                JSON[j-1]='\0';
                return;
        }


        // for all other messages, get MQTT_ID (4th field) then convert to json
        j=0;
        i+=4; // skip ";MQTT_ID="

        while(line[i] != ';' && i < BUFFER_SIZE && j < MAX_DATA_LEN) {
                MQTT_ID[j++] = line[i++];
        }
        MQTT_ID[j] = '\0';

        // continue with json convertion
        readRfLinkFields(line, i+1);
}


/**
 * Extract fields and convert them to a json string
 */
void readRfLinkFields(char* fields, int start){

        int strpos=start;
        int fldpos=0;
        int valueType=0;

        JSON[0]='{';
        JSON[1]='\0';

        while(strpos < BUFFER_SIZE-start && fields[strpos] != '\n' && fields[strpos] != '\0') {

                // if current char is "=", we end name parsing and start parsing the field's value
                if(fields[strpos] == '=') {
                        FIELD_BUF[fldpos]='\0';
                        fldpos=0;

                        // Tag field regarding the name...
                        if(RfLinkFieldIsString(FIELD_BUF)) valueType=RFLINK_VALUE_TYPE_STRING;
                        else if(RfLinkFieldIsOregon(FIELD_BUF)) valueType=RFLINK_VALUE_TYPE_OREGON;
                        else if(RfLinkFieldIsHexInteger(FIELD_BUF)) valueType=RFLINK_VALUE_TYPE_INTEGER;
                        else valueType=RFLINK_VALUE_TYPE_RAWVAL;

                        RfLinkFieldAddQuotedValue(FIELD_BUF);

                        // if current char is ";", we end parsing value and start parsing another field's name
                } else if(fields[strpos] == ';') {

                        FIELD_BUF[fldpos]='\0';
                        fldpos=0;
                        strcat(JSON,":");

                        // Handle special cases...
                        switch(valueType) {
                        case RFLINK_VALUE_TYPE_STRING:  RfLinkFieldAddQuotedValue(FIELD_BUF); break;
                        case RFLINK_VALUE_TYPE_OREGON:  RfLinkFieldAddOregonValue(FIELD_BUF); break;
                        case RFLINK_VALUE_TYPE_INTEGER: RfLinkFieldAddIntegerValue(FIELD_BUF); break;
                        default: strcat(JSON,FIELD_BUF);
                        }

                        strcat(JSON,",");
                } else { // default case : copy current char
                        FIELD_BUF[fldpos++]=fields[strpos];
                }

                strpos++;
        }

        int len = strlen(JSON);
        JSON[len-1]='}';
}


/**
 * check wether a given string is in a PROGMEN array of strings
 */
bool RfLinkIsStringInArray(char *buffer, const char* const strArray[]) {
        int i = 0;
        char stringptr[40];
        do {
                strcpy_P(stringptr,strArray[i]);
                if (stringptr[0] != '\0') {
                        if(strcmp(buffer, stringptr)==0) return true;
                        i++;
                }
        }
        while(stringptr[0] != '\0');
        return false;
}


/**
 * check if a given field name is used for string (thus need quotes in JSON message)
 */
bool RfLinkFieldIsString(char *buffer) {
        return RfLinkIsStringInArray(buffer, RFLINK_FIELD_STRING);
}


/**
 * check if a given field name is used for hex integer (thus need to be converted to dec)
 */
bool RfLinkFieldIsHexInteger(char *buffer) {
        return RfLinkIsStringInArray(buffer, RFLINK_FIELD_HEXINT);
}


/**
 * check if a given field name is used for Oregon temperature (thus need to be converted to float)
 */
bool RfLinkFieldIsOregon(char *buffer) {
    return RfLinkIsStringInArray(buffer, RFLINK_FIELD_HEXFLOAT10);
}


/**
 * put the value as a quoted one in the JSON buffer
 */
void RfLinkFieldAddQuotedValue(char *buffer) {
        strcat(JSON,"\"");
        strcat(JSON,buffer);
        strcat(JSON,"\"");
}


/**
 * convert a string to float value and put it in the JSON buffer
 * eg : 0x00c3 which is 216 (dec) will become 21.6
 */
void RfLinkFieldAddOregonValue(char *buffer) {
        char strfloat[4];
        dtostrf(strtoul(buffer,NULL,16)*0.1, 2, 1, strfloat);
        strfloat[4]='\0';
        strcat(JSON,strfloat);
}


/**
 * put the value as an integer in the JSON buffer
 * eg: 0x57 will become 87
 */
void RfLinkFieldAddIntegerValue(char *buffer) {
        char s[21];
        strcat(JSON, ultoa(strtoul(buffer,NULL,16),s,10));
}