c++: Added the ability to initialise a class using a context struct

Signed-off-by: Houman Brinjcargorabi <houman.brinjcargorabi@intel.com>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/mraa/aio.hpp

@@ -47,13 +47,26 @@ class Aio
      *
      * @param pin channel number to read ADC inputs
      */
-    Aio(unsigned int pin)
+    Aio(int pin)
     {
         m_aio = mraa_aio_init(pin);
         if (m_aio == NULL) {
             throw std::invalid_argument("Invalid AIO pin specified - do you have an ADC?");
         }
     }
+    /**
+     * Aio Constructor, takes a pointer to the AIO context and initialises
+     * the AIO class
+     *
+     * @param void * to an AIO context
+     */
+    Aio(void* aio_context)
+    {
+        m_aio = (mraa_aio_context) aio_context;
+        if (m_aio == NULL) {
+            throw std::invalid_argument("Invalid AIO context");
+        }
+    }
     /**
      * Aio destructor
      */

api/mraa/gpio.hpp

@@ -107,6 +107,19 @@ class Gpio
             mraa_gpio_owner(m_gpio, 0);
         }
     }
+    /**
+     * Gpio Constructor, takes a pointer to the GPIO context and initialises
+     * the GPIO class
+     *
+     * @param void * to GPIO context
+     */
+    Gpio(void* gpio_context)
+    {
+        m_gpio = (mraa_gpio_context) gpio_context;
+        if (m_gpio == NULL) {
+            throw std::invalid_argument("Invalid GPIO context");
+        }
+    }
     /**
      * Gpio object destructor, this will only unexport the gpio if we where
      * the owner

api/mraa/i2c.hpp

@@ -62,6 +62,18 @@ class I2c
             throw std::invalid_argument("Invalid i2c bus");
         }
     }
+    /**
+     * I2C constructor, takes a pointer to a I2C context and initialises the I2C class
+     *
+     * @param void * to an I2C context
+     */
+    I2c(void* i2c_context)
+    {
+        m_i2c = (mraa_i2c_context) i2c_context;
+        if (m_i2c == NULL) {
+            throw std::invalid_argument("Invalid I2C context");
+        }
+    }
 
     /**
      * Closes the I2c Bus used. This does not guarrantee the bus will not

api/mraa/pwm.hpp

@@ -66,6 +66,20 @@ class Pwm
             mraa_pwm_owner(m_pwm, 0);
         }
     }
+
+    /**
+     * Pwm constructor, takes a pointer to the PWM context and
+     * initialises the class
+     *
+     * @param void * to a PWM context
+     */
+    Pwm(void* pwm_context)
+    {
+        m_pwm = (mraa_pwm_context) pwm_context;
+        if (m_pwm == NULL) {
+            throw std::invalid_argument("Invalid PWM context");
+        }
+    }
     /**
      * Pwm destructor
      */

api/mraa/spi.hpp

@@ -79,6 +79,20 @@ class Spi
         }
     }
 
+    /**
+     * Spi Constructor, takes a pointer to a SPI context and initialises
+     * the SPI class
+     *
+     * @param void * to SPI context
+     */
+    Spi(void* spi_context)
+    {
+        m_spi = (mraa_spi_context) spi_context;
+        if (m_spi == NULL) {
+            throw std::invalid_argument("Invalid SPI context");
+        }
+    }
+
     /**
      * Closes spi bus
      */

api/mraa/uart.hpp

@@ -75,6 +75,20 @@ class Uart
         }
     }
 
+    /**
+     * Uart Constructor, takes a pointer to the UART context and initialises
+     * the UART class
+     *
+     * @param void * to a UART context
+     */
+    Uart(void* uart_context)
+    {
+        m_uart = (mraa_uart_context) uart_context;
+
+        if (m_uart == NULL) {
+            throw std::invalid_argument("Invalid UART context");
+        }
+    }
     /**
      * Uart destructor
      */