LibULPNode_RF_Protocol.cpp

// **********************************************************************************
// ULPNode RF protocol paylaods used for transmission
// **********************************************************************************
// Creative Commons Attrib Share-Alike License
// You are free to use/extend this library but please abide with the CC-BY-SA license:
// http://creativecommons.org/licenses/by-sa/4.0/
//
// For any explanation of ULPNode RF Protocol see
// https://hallard.me/ulpnode-rf-protocol/
//
// For any explanation of ULPNode see
// https://hallard.me/category/ulpnode/
//
// Written by Charles-Henri Hallard (http://hallard.me)
//
// History : V1.00 2014-07-14 - First release
//         : V1.10 2015-09-03 - Added Particle Photon/Core targets
//
// All text above must be included in any redistribution.
//
// **********************************************************************************
#include "LibULPNode_RF_Protocol.h"

#ifdef ARDUINO
#include <Arduino.h>
#endif


// Buffer used to decode specific data value
char pbuf[24];

// Buffer containing JSON data string to return
char json_str[128];

/* ======================================================================
Function: ftoa
Purpose : convert float value to string
Input   : float
          buffer to put result
          number of precision digits
Output  : string len
Comments: Author : TRAMPAS STERN
          this code was found on the web and modified to actually work.
          for now needed by cloud compile of photon, does not support
          float printf nor dtostrf, amazing !!!
====================================================================== */
int ftoa(float x, char *str, char prec)
{
  int k;
  int8_t ie, i, ndig;
  char *start = str;

  // Based on precision, set the number of digits.
  ndig = prec + 1;

  if(prec > 12)
    ndig = 13;

  ie = 0;

  // If x is negative, write minus sign and reverse.
  if(x < 0)  {
    *str++ = '-';
    x = -x;
  }

  // If (x < 0.0) then increment by 10 until between 1.0 and 10.0.
  if(x != 0.0) {
    while (x < 1.0) {
      x =x* 10.0;
      ie--;
    }
  }

  // If x > 10 then let's shift it down.
  while(x >= 10.0) {
    x = x * (1.0/10.0);
    ie++;
  }

  // In f format, the number of digits is related to size.
  ndig = ndig + ie;

  if(prec == 0 && (ie > ndig) )
   ndig=ie;

  // Check and see if the number is less than 1.0
  if(ie<0) {
    *str++ = '0';

    if(prec!=0)
      *str++ = '.';

    if(ndig < 0)
      ie = ie-ndig;  // Limit zeros if underflow

    for(i = -1; i > ie; i--)
      *str++ = '0';
  }

    // For each digit.
  for(i=0; i < ndig; i++) {
    float b;
    k = x;             // k = most significant digit
    *str++ = k + '0';  // Output the char representation

    if( i==ie && prec!=0)
      *str++ = '.';   // Output a decimal point

    b = (float)k;

    // Multiply by 10 before subtraction to remove
    // errors from limited number of bits in float.
    b = b*10.0;
    x = x*10.0;
    x = x - b;      // Subtract k from x
  }

  *str++ = '\0';
  return (str - start);  // Return string length
}

/* ======================================================================
Function: decode_bat
Purpose : print the battery voltage value
Input   : battery (mV)
          index of sensor number (0 to 3)
====================================================================== */
char * decode_bat(uint16_t bat, char * index)
{
  sprintf_P(pbuf, PSTR("\"bat%s\":"), index);

  #ifdef ARDUINO
    dtostrf(bat/1000.0f, 5, 3, pbuf+strlen(pbuf));
  #else
    ftoa(bat/1000.0f, pbuf+strlen(pbuf), 3 );
    //sprintf(pbuf, "\"bat%s\":%.3f", index, bat/1000.0f );
  #endif

  return pbuf;
}

/* ======================================================================
Function: decode_lowbat
Purpose : print low bat state
Input   : true if low bat
====================================================================== */
char * decode_lowbat(uint8_t low, char * index)
{
  sprintf_P(pbuf, PSTR("\"lowbat%s\":%c"), index, '0'+low);
  return pbuf;
}

/* ======================================================================
Function: decode_volt
Purpose : print the voltage value
Input   : voltage (mV)
          index of sensor number (0 to 3)
====================================================================== */
char * decode_volt(uint16_t volt, char * index)
{
  // convert voltage to V format xx.yyy
  sprintf_P(pbuf, PSTR("\"volt%s\":%s"), index);
  #ifdef ARDUINO
    dtostrf(volt/1000.0f, 5, 3, pbuf+strlen(pbuf));
  #else
    ftoa(volt/1000.0f, pbuf+strlen(pbuf), 3 );
  #endif

  return pbuf;
}

/* ======================================================================
Function: decode_temp
Purpose : print the temperature value
Input   : temp (*100)
          index of sensor number (0 to 3)
====================================================================== */
char * decode_temp(int16_t temp, char * index)
{
  // convert temperature to format xx.yy
  sprintf_P(pbuf, PSTR("\"temp%s\":"), index);
  #ifdef ARDUINO
    dtostrf(temp/100.0f, 4, 2,  pbuf+strlen(pbuf));
  #else
    ftoa(temp/100.0f, pbuf+strlen(pbuf), 2 );
  #endif

  return pbuf;
}

/* ======================================================================
Function: decode_hum
Purpose : print the humidity
Input   : humidity (*10)
          index of sensor number (0 to 3)
====================================================================== */
char * decode_hum(uint16_t hum, char * index)
{
  sprintf_P(pbuf, PSTR("\"hum%s\":"), index);
  #ifdef ARDUINO
    dtostrf(hum/10.0f, 4, 1,  pbuf+strlen(pbuf));
  #else
    ftoa(hum/10.0f, pbuf+strlen(pbuf), 1 );
  #endif
  return pbuf;
}

/* ======================================================================
Function: decode_lux
Purpose : print the lux value
Input   : lux (*10)
          index of sensor number (0 to 3)
====================================================================== */
char * decode_lux(uint16_t lux, char * index)
{
  sprintf_P(pbuf, PSTR("\"lux%s\":"), index);
  #ifdef ARDUINO
    dtostrf(lux/10.0f, 3, 1,  pbuf+strlen(pbuf));
  #else
    ftoa(lux/10.0f, pbuf+strlen(pbuf), 1 );
  #endif
  return pbuf;
}

/* ======================================================================
Function: decode_co2
Purpose : print the co2 value
Input   : co2
          index of sensor number (0 to 3)
====================================================================== */
char * decode_co2(uint16_t co2, char * index)
{
  sprintf_P(pbuf, PSTR("\"co2%s\":%d"), index, co2);
  return pbuf;
}

/* ======================================================================
Function: decode_rssi
Purpose : print the rssi value
Input   : rssi
          index of sensor number (0 to 3)
====================================================================== */
char * decode_rssi(int8_t rssi, char * index)
{
  sprintf_P(pbuf, PSTR("\"rssi%s\":%d"), index, rssi);
  return pbuf;
}

/* ======================================================================
Function: decode_counter
Purpose : print a counter value
Input   : counter
          index of sensor number (0 to 3)
====================================================================== */
char * decode_counter(uint32_t counter, char * index)
{
  sprintf_P(pbuf, PSTR("\"count%s\":%ld"), index, counter);
  return pbuf;
}

/* ======================================================================
Function: decode_digital_io
Purpose : print a digital IO value
Input   : Digital IO value
          digital pin (0 to 16)
====================================================================== */
char * decode_digital_io(uint8_t value, uint8_t pin)
{
  sprintf_P(pbuf, PSTR("\"d%d\":%d"), pin, value);
  return pbuf;
}

/* ======================================================================
Function: decode_analog_io
Purpose : print a analog IO value
Input   : analog value
          analog pin (0 to 7)
====================================================================== */
char * decode_analog_io(uint16_t value, uint8_t pin)
{
  sprintf_P(pbuf, PSTR("\"a%d\":%ld"), pin, value);
  return pbuf;
}

/* ======================================================================
Function: add_json_data
Purpose : Add json data to json string
Input   : json global buffer
          json data to add
Comments: -
====================================================================== */
char * add_json_data(char * str, char * json)
{
  uint8_t l = strlen(str);

  // Some checking on size, just in case
  if ( l + strlen(json) < sizeof(json_str))
    sprintf_P(&str[l], PSTR(",%s"), json);

  return str;
}

/* ======================================================================
Function: decode_frame_type
Purpose : print the frame type
Input   : type
Output  : string to decoded packet type name
Comments: -
====================================================================== */
char * decode_frame_type(uint8_t type)
{
  // check command type is known
  if (!isPayloadValid(type))
    type =0;

  if (type == RF_PL_ALIVE )             strcpy_P(pbuf, PSTR("ALIVE"));
  else if (type == RF_PL_PING )         strcpy_P(pbuf, PSTR("PING"));
  else if (type == RF_PL_PINGBACK )     strcpy_P(pbuf, PSTR("PINGBACK"));
  else if (type == RF_PL_OTA_CONFIG )   strcpy_P(pbuf, PSTR("OTA_CONFIG"));
  else if (type == RF_PL_OTA_UPDATE )   strcpy_P(pbuf, PSTR("OTA_UPDATE"));
  else if (type == RF_PL_DHCP_REQUEST ) strcpy_P(pbuf, PSTR("DHCP_REQUEST"));
  else if (type == RF_PL_DHCP_OFFER )   strcpy_P(pbuf, PSTR("DHCP_OFFER"));
  else if (type == RF_PL_ACK )          strcpy_P(pbuf, PSTR("ACK"));
  else if (type == RF_PL_SENSOR_DATA )  strcpy_P(pbuf, PSTR("DATA"));
  else
    strcpy_P(pbuf, PSTR("UNKNOWN"));

  // I did not succeded to do better with array of flash string in Arduino
  //#if defined(ARDUINO) && !defined(ESP8266)
  //  strcpy_P(pbuf, (char*)pgm_read_word(&(rf_frame[type])));
  //#else
  //  strcpy_P(pbuf, PSTR(rf_frame[type]));
  //#endif

  return pbuf;
}

/* ======================================================================
Function: decode_received_data
Purpose : send to serial received data in human format
Input   : node id (0 if you don't want to have it into json string)
          rssi of data received
          size of data
          command of frame received
          pointer to the data
Output  : command code validated by payload size type reveived
Comments: if we had a command and payload does not match
          code as been set to 0 to avoid check in next
====================================================================== */
uint8_t decode_received_data(uint8_t nodeid, int8_t rssi, uint8_t len, uint8_t c, uint8_t * ppayload)
{
  char *    pjson = json_str;
  uint8_t * pdat = ppayload;

  // Start our buffer string
  if (nodeid)
    sprintf_P(json_str, PSTR("{\"id\":%d,\"rssi\":%d"), nodeid, rssi);
  else
    sprintf_P(json_str, PSTR("{\"rssi\":%d"), rssi);

  // this is for known packet command
  // Alive packet ?
  if ( c==RF_PL_ALIVE && len==sizeof(RFAlivePayload)) {
    sprintf_P(pbuf, PSTR("\"state\":%d"), ((RFAlivePayload*)pdat)->status);
    add_json_data(json_str, pbuf);
    add_json_data(json_str, decode_bat(((RFAlivePayload*)pdat)->vbat, (char*)""));

  // ping/ping back packet ?
  } else if ( (c==RF_PL_PING || c==RF_PL_PINGBACK) && len==sizeof(RFPingPayload)) {
    sprintf_P(pbuf, PSTR("\"state\":%d"), ((RFAlivePayload*)pdat)->status);
    add_json_data(json_str, pbuf);
    // Vbat is sent only on emiting ping packet, not ping back
    if (c==RF_PL_PING )
      add_json_data(json_str, decode_bat(((RFPingPayload*)pdat)->vbat, (char*)""));

    // RSSI from other side is sent only in pingback response
    // this is the 2nd rssi value, we call it myrssi
    if (c==RF_PL_PINGBACK){
      sprintf_P(pbuf, PSTR("\"myrssi\":%d"), rssi);
      add_json_data(json_str, pbuf);
    }
  // payload Packet with datas
  // we need at least size of payload > 2
  // 1 payload command + 1 sensor type + 1 sensor data)
  // and is one of our known data code. This is for received data
  } else if ( isPayloadData(c) && len>2) {
    uint8_t data_size ;
    uint8_t data_type ;
    uint8_t l ;
    char *  pval;
    boolean error ;

    // Ok we set up on 1st data field
    data_type = *(++pdat);
    l = len -1;

    // Loop through all data contained into the payload
    // discard 1st byte on each, which is header data code
    do {
      // each sensor type can have 4 values sent,
      char str_idx[] = " ";
      data_size = 0;
      pval= NULL;
      error = false;

      // If index of sensor value is > 0 change string
      // label adding the index if at least 2 values
      // i.e if 2 sensor temp are sent/received the
      // result will look in JSON like
      // ie : {temp:20.1, temp1:22.11, ...}
      *str_idx = '0' + (data_type & ~RF_DAT_SENSOR_MASK);

      // the first we don't add index number this save 1 char
      if (*str_idx=='0')
        *str_idx='\0';

      if (isDataTemp(data_type) && l>=sizeof(s_temp)) {
        // Temperature, and have enought data ?
        pval = decode_temp(((s_temp*)pdat)->temp, str_idx);
        data_size = sizeof(s_temp);
      } else if (isDataHum(data_type) && l>=sizeof(s_hum)) {
        // Humidity, and have enought data ?
        pval = decode_hum(((s_hum*)pdat)->hum, str_idx);
        data_size = sizeof(s_hum);
      } else if (isDataLux(data_type) && l>=sizeof(s_lux)) {
        // Luminosity and have enought data ?
        pval =  decode_lux(((s_lux*)pdat)->lux, str_idx);
        data_size = sizeof(s_lux);
      } else if (isDataCO2(data_type) && l>=sizeof(s_co2)) {
        // CO2 and have enought data ?
        pval = decode_co2(((s_co2*)pdat)->co2, str_idx);
        data_size = sizeof(s_co2);
      } else if (isDataVolt(data_type) && l>=sizeof(s_volt)) {
        // voltage and have enought data ?
        pval = decode_volt(((s_volt*)pdat)->volt, str_idx);
        data_size = sizeof(s_volt);
      }  else if (isDataBat(data_type) && l>=sizeof(s_volt)) {
        // battery (same payload as volt) and have enought data ?
        pval = decode_bat(((s_volt*)pdat)->volt, str_idx);
        data_size = sizeof(s_volt);
      } else if (isDataRSSI(data_type) && l>=sizeof(s_rssi)) {
        // RSSI and have enought data ?
        pval =  decode_rssi(((s_rssi*)pdat)->rssi, str_idx);
        data_size = sizeof(s_rssi);
      } else if (isDataCounter(data_type) && l>=sizeof(s_counter)) {
        // counter and have enought data ?
        pval =  decode_counter(((s_counter*)pdat)->counter, str_idx);
        data_size = sizeof(s_counter);
      } else if (isDataLowBat(data_type) && l>=sizeof(s_lowbat)) {
        // lowbat and have enought data ?
        pval =  decode_lowbat(((s_lowbat*)pdat)->lowbat, str_idx);
        data_size = sizeof(s_lowbat);
      } else if (isDataDigitalIO(data_type) && l>=sizeof(s_io_digital)) {
        // digital I/0
        pval =  decode_digital_io(((s_io_digital*)pdat)->digital,
                                  ((s_io_digital*)pdat)->code - RF_DAT_IO_DIGITAL);
        data_size = sizeof(s_io_digital);
      } else if (isDataAnalogIO(data_type) && l>=sizeof(s_io_analog)) {
        // analog I/O
        pval =  decode_analog_io(((s_io_analog*)pdat)->analog,
                                 ((s_io_analog*)pdat)->code - RF_DAT_IO_ANALOG);
        data_size = sizeof(s_io_analog);
      } else {
        // Unknown data code, so we can't check data value
        // nor size, so we decide to discard the
        // end of this frame
        ULPNP_DebugF("Parsing error");
        error = true;
      }

      /*
      ULPNP_DebugF("[0x");
      ULPNP_Debug(data_type,HEX);
      ULPNP_DebugF("] -> l=");
      ULPNP_Debug(l);
      ULPNP_DebugF(" added=");
      ULPNP_Debug(data_size);
      ULPNP_DebugF(" pval='");
      ULPNP_Debug(pval);
      ULPNP_DebugF("' next=");
      */

      // Something to add ?
      if (!error && data_size && pval) {
        // Add to JSon string
        add_json_data(json_str, pval);

        // remove data size we just worked on
        l-= data_size;

        // Rest some data after the code
        if (l>=2) {
          pdat+=data_size; // Pointer to next data on buffer
          data_type=*pdat; // get next data field

          //ULPNP_Debug(data_type,HEX);
        } else {
          //ULPNP_DebugF("none");
        }
      }
      //ULPNP_Debugln();
    } // while data
    while(l>1 && !error);

  // not known data code, raw display packet
  } else {
    uint8_t * p = (uint8_t *) ppayload;

    // send raw values
    strcat(json_str, ",\"raw\":\"");

    // Add each received value
    while (len--)
      sprintf_P(&json_str[strlen(json_str)], PSTR("%02X "), *p++);

    strcat(json_str, "\"");

    // here we did not validated known packet, so clear command
    // code for the rest of the operation
    c=0;
  }

  // End our buffer string
  strcat(json_str, "}");

  return (c);
}