DFRORP: Add string based constructor

Signed-off-by: Adelin Dobre <adelin.dobre@rinftech.com>

src/dfrorp/dfrorp.cxx

@@ -26,6 +26,7 @@
 #include <stdexcept>
 
 #include "dfrorp.hpp"
+#include "upm_string_parser.hpp"
 
 using namespace upm;
 using namespace std;
@@ -38,6 +39,75 @@ DFRORP::DFRORP(int apin, float a_ref) :
                              + ": dfrorp_init() failed");
 }
 
+DFRORP::DFRORP(std::string initStr) : mraaIo(initStr)
+{
+  mraa_io_descriptor* descs = mraaIo.getMraaDescriptors();
+  std::vector<std::string> upmTokens;
+  
+  if(!mraaIo.getLeftoverStr().empty()) {
+    upmTokens = UpmStringParser::parse(mraaIo.getLeftoverStr());
+  }
+  
+  m_dfrorp = (dfrorp_context)malloc(sizeof(struct _dfrorp_context));
+  
+  if (!m_dfrorp)
+    throw std::runtime_error(string(__FUNCTION__)
+                             + ": dfrorp_init() failed");
+  
+  memset((void *)m_dfrorp, 0, sizeof(struct _dfrorp_context));
+  
+  m_dfrorp->aio = NULL;
+
+  m_dfrorp->offset = 0.0;
+  m_dfrorp->scale = 1.0;
+
+  // make sure MRAA is initialized
+  int mraa_rv;
+  if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
+  {
+    dfrorp_close(m_dfrorp);
+    throw std::runtime_error(std::string(__FUNCTION__) 
+                             + ": mraa_init() failed");
+  }
+  
+  if(!descs->aios)
+  {
+    dfrorp_close(m_dfrorp);
+    throw std::runtime_error(std::string(__FUNCTION__) 
+                             + ": mraa_aio_init() failed");    
+  }
+  else 
+  {
+    if( !(m_dfrorp->aio = descs->aios[0]) )
+    {
+      dfrorp_close(m_dfrorp);
+      throw std::runtime_error(std::string(__FUNCTION__) 
+                              + ": mraa_aio_init() failed");          
+    }
+  }
+  
+  // set our analog resolution
+  m_dfrorp->a_res = (float)(1 << mraa_aio_get_bit(m_dfrorp->aio)) - 1;
+
+  for (std::string tok : upmTokens) {
+    if(tok.substr(0,6) == "a_ref:")
+      m_dfrorp->a_ref = std::stof(tok.substr(6));
+    if(tok.substr(0,10) == "setOffset:") {
+      float offset = std::stof(tok.substr(10));
+      setOffset(offset);
+    }
+    if(tok.substr(0,9) == "setScale:") {
+      float scale = std::stof(tok.substr(9));
+      setScale(scale);
+    }
+    if(tok.substr(0,21) == "setCalibrationOffset:") {
+      float offset = std::stof(tok.substr(21));
+      setCalibrationOffset(offset);
+    }
+  }
+  
+}
+
 DFRORP::~DFRORP()
 {
   dfrorp_close(m_dfrorp);

src/dfrorp/dfrorp.hpp

@@ -25,12 +25,14 @@
 
 #include <string>
 #include <iostream>
-
+#include <vector>
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
 
 #include "dfrorp.h"
+#include <mraa/initio.hpp>
+
 
 namespace upm {
   /**
@@ -81,6 +83,13 @@ namespace upm {
      */
     DFRORP(int apin, float a_ref=5.0);
 
+    /**
+     * Instantiates DFRobot object based on a given string.
+     *
+     * @param initStr string containing specific information for DFRobot initialization.
+     */
+    DFRORP(std::string initStr);
+
     /**
      * DFRORP object destructor
      */
@@ -155,6 +164,7 @@ namespace upm {
   protected:
     // dfrorp device context
     dfrorp_context m_dfrorp;
+    mraa::MraaIo mraaIo;
 
   private:
     /* Disable implicit copy and assignment operators */