DFRPH: Add string based constructor

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

src/dfrph/dfrph.c

@@ -24,6 +24,7 @@
 
 #include <string.h>
 #include <stdlib.h>
+#include <assert.h>
 
 #include "dfrph.h"
 
@@ -60,7 +61,11 @@ dfrph_context dfrph_init(int16_t pin)
 
 void dfrph_close(dfrph_context dev)
 {
-    mraa_aio_close(dev->aio);
+    assert(dev != NULL);
+  
+    if(dev->aio)
+        mraa_aio_close(dev->aio);
+    
     free(dev);
 }
 

src/dfrph/dfrph.cxx

@@ -26,6 +26,7 @@
 #include <stdexcept>
 
 #include "dfrph.hpp"
+#include "upm_string_parser.hpp"
 
 using namespace upm;
 
@@ -36,6 +37,63 @@ DFRPH::DFRPH(int pin, float vref) : _dev(dfrph_init(pin))
                 ": dfrph_init() failed, invalid pin?");
 }
 
+DFRPH::DFRPH(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());
+    }
+    
+    _dev = (dfrph_context) malloc(sizeof(struct _dfrph_context));
+
+    if(!_dev)
+        throw std::runtime_error(std::string(__FUNCTION__)
+                                + ": dfrph_init() failed");
+    
+    // make sure MRAA is initialized
+    int mraa_rv;
+    if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
+    {
+      dfrph_close(_dev);
+      throw std::runtime_error(std::string(__FUNCTION__) 
+                              + ": mraa_init() failed");
+    }
+
+    if(!descs->aios)
+    {
+      dfrph_close(_dev);
+      throw std::runtime_error(std::string(__FUNCTION__) 
+                              + ": mraa_aio_init() failed");    
+    }
+    else 
+    {
+      if( !(_dev->aio = descs->aios[0]) )
+      {
+        dfrph_close(_dev);
+        throw std::runtime_error(std::string(__FUNCTION__) 
+                                + ": mraa_aio_init() failed");          
+      }
+    }
+    
+    /* Set the ref, offset, and scale */
+    _dev->m_aref = 5.0;
+    _dev->m_offset = 0.0;
+    _dev->m_scale = 1.0; 
+    
+    for (std::string tok : upmTokens) {
+        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);
+        }
+    }    
+}
+
 DFRPH::~DFRPH()
 {
     dfrph_close(_dev);

src/dfrph/dfrph.hpp

@@ -25,8 +25,10 @@
 
 #include <iostream>
 #include <string>
+#include <vector>
 
 #include "dfrph.h"
+#include <mraa/initio.hpp>
 
 namespace upm {
   /**
@@ -99,6 +101,13 @@ namespace upm {
      */
     DFRPH(int pin, float vref = 5.0);
 
+    /**
+     * Instantiates DFRPH object based on a given string.
+     *
+     * @param initStr string containing specific information for DFRPH initialization.
+     */
+    DFRPH(std::string initStr);
+    
     /**
      * DFRPH destructor
      */
@@ -139,6 +148,7 @@ namespace upm {
     DFRPH &operator=(const DFRPH &) {return *this;}
 
     dfrph_context _dev;
+    mraa::MraaIo mraaIo;
   };
 }