Introduced polymorphic interface for A4988 driver

.gitignore

@@ -1,4 +1,4 @@
-
+*.swp
 main
 
 # Created by https://www.toptal.com/developers/gitignore/api/c++

drivers/a4988.cpp

@@ -3,10 +3,13 @@
 #include <queue>
 #include <cmath>
 #include <thread>
+#include <string>
+#include <memory>
 
 #include <iostream>
 
 namespace simon {
+  namespace a4988 {
   c_allegro_4988::c_allegro_4988(a4988_settings_t* pset)
     : m_pset(pset), m_initialized(false), m_alive(true)
   {
@@ -21,16 +24,20 @@ namespace simon {
     {
       std::cout << "In thread" << std::endl;
       if (!m_queue.empty()) {
-        auto& move = m_queue.front();
+        auto cmd = m_queue.front();
-        if (!set_pwm_freq(std::round(1e6/move.period_us))) {
+        // Distinguish between different tytpes of commands and derive type
+        if (*cmd == "move") {
+          auto move = std::static_pointer_cast<c_move>(cmd);
+          if (!set_pwm_freq(std::round(1e6/move->period_us))) {
             // TODO: proper error handling
           }
           gpioHardwarePWM(m_pset->gpio_step, m_pwm_freq, PI_HW_PWM_RANGE/2);
-        gpioWrite(m_pset->gpio_dir, move.dir);
+          gpioWrite(m_pset->gpio_dir, move->dir);
-        std::cout << move.period_us << " - " << move.steps << std::endl;
+          std::cout << move->period_us << " - " << move->steps << std::endl;
-        auto t_sleep = move.period_us*move.steps;
+          auto t_sleep = move->period_us*move->steps;
           std::this_thread::sleep_for(std::chrono::microseconds(t_sleep));
           gpioHardwarePWM(m_pset->gpio_step, m_pwm_freq, 0);
+        }
         m_queue.pop();
       }
       else {
@@ -38,9 +45,9 @@ namespace simon {
       }
     }
   }
-  void c_allegro_4988::post(move_t move)
+  void c_allegro_4988::post(std::shared_ptr<c_cmd> cmd)
   {
-    m_queue.push(move);
+    m_queue.push(cmd);
   }
   void c_allegro_4988::initialize(void)
   {
@@ -83,5 +90,5 @@ namespace simon {
     m_pwm_freq = pwm_freq;
     return 0;
   }
-
+ } // namespace a4988
-}
+} // namespace simon

include/a4988.h

@@ -6,9 +6,11 @@
 #define CFG_DEPRECATED_ARG      0
 
 #include <queue>
+#include <string>
+#include <memory>
 
 namespace simon {
-
+  namespace a4988 {
     typedef struct
     {
         const unsigned gpio_en;
@@ -17,13 +19,33 @@ namespace simon {
         const bool gpio_microsteps[3];
       } a4988_settings_t;
 
-  typedef struct
+    class c_cmd
+    {
+      public:
+        explicit c_cmd(const std::string cmd) : m_cmd(cmd) {}
+        bool operator==(const std::string& vgl) {
+          return (vgl==m_cmd ? true : false);
+        }
+        virtual ~c_cmd(void) noexcept {}
+      private:
+        const std::string m_cmd;
+    };
+
+    class c_move : public c_cmd
     {
+      public:
         unsigned steps;
         bool dir;
         unsigned period_us;
-  } move_t;
+        explicit c_move(void) : c_cmd("move"){}
+    };
 
+    class c_enable : public c_cmd
+    {
+      public:
+        bool enabled;
+        explicit c_enable(void) : c_cmd("enable"){}
+    };
 
     class c_allegro_4988
     {
@@ -31,19 +53,19 @@ namespace simon {
         c_allegro_4988(a4988_settings_t* set);
         int enable(void);
         int disable(void);
-      void post(move_t move);
+        void post(std::shared_ptr<c_cmd> cmd);
         void run(void);
       private:
         a4988_settings_t* m_pset;
         bool m_initialized;
-      std::queue<move_t> m_queue;
+        std::queue<std::shared_ptr<c_cmd>> m_queue;
         unsigned m_pwm_freq;
         bool m_alive;
       private:
         void initialize(void);
         int set_pwm_freq(const unsigned pwm_freq);
     };
-
+  } // namespace a4988
 } // namespace simon
 
 #endif /*INCLUDED_DRIVER_ALLEGRO_4988*/

main.cpp

@@ -2,10 +2,11 @@
 #include <include/a4988.h>
 #include <thread>
 #include <functional>
+#include <memory>
 
 int main()
 {
-  using namespace simon;
+  using namespace simon::a4988;
   a4988_settings_t a4988_set{
     .gpio_en = 17,
     .gpio_step = 18,
@@ -15,9 +16,13 @@ int main()
     }
   };
   c_allegro_4988 a4988(&a4988_set);
-  move_t move{32768, true, 100};
+  auto move(std::make_shared<c_move>());
+  move->steps = 32768;
+  move->dir = true;
+  move->period_us = 1000;
+  auto cmd = std::static_pointer_cast<c_cmd>(move);
   std::thread t1(std::bind(&c_allegro_4988::run, &a4988));
-  a4988.post(move);
+  a4988.post(cmd);
   t1.join();
   std::cout << "Hello camera" << std::endl;
   return 0;