python: Support building of both python2 & python3 bindings

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

src/python/mraapython.i

@@ -0,0 +1,163 @@
+%include typemaps.i
+%include carrays.i
+
+%array_class(uint8_t, uint8Array);
+
+// uart write()
+%typemap(in) (const char* data, int length) {
+  if (PyByteArray_Check($input)) {
+    // whilst this may seem 'hopeful' it turns out this is safe
+    $1 = (char*) PyByteArray_AsString($input);
+    $2 = PyByteArray_Size($input);
+  } else {
+    PyErr_SetString(PyExc_ValueError, "bytearray expected");
+    return NULL;
+  }
+}
+
+// i2c write()
+%typemap(in) (const uint8_t *data, int length) {
+  if (PyByteArray_Check($input)) {
+    // whilst this may seem 'hopeful' it turns out this is safe
+    $1 = (uint8_t*) PyByteArray_AsString($input);
+    $2 = PyByteArray_Size($input);
+  } else {
+    PyErr_SetString(PyExc_ValueError, "bytearray expected");
+    return NULL;
+  }
+}
+
+// Spi write()
+%typemap(in) (uint8_t *txBuf, int length) {
+  if (PyByteArray_Check($input)) {
+    // whilst this may seem 'hopeful' it turns out this is safe
+    $1 = (uint8_t*) PyByteArray_AsString($input);
+    $2 = PyByteArray_Size($input);
+  } else {
+    PyErr_SetString(PyExc_ValueError, "bytearray expected");
+    return NULL;
+  }
+}
+
+namespace mraa {
+class I2c;
+%typemap(out) uint8_t*
+{
+  // need to loop over length
+  $result = PyByteArray_FromStringAndSize((char*) $1, arg2);
+  free($1);
+}
+
+class Spi;
+%typemap(out) uint8_t*
+{
+  // need to loop over length
+  $result = PyByteArray_FromStringAndSize((char*) $1, arg3);
+  free($1);
+}
+}
+
+%newobject I2c::read(uint8_t *data, int length);
+%newobject Spi::write(uint8_t *data, int length);
+%newobject Uart::read(char* data, int length);
+%newobject Spi::transfer(uint8_t *txBuf, uint8_t *rxBuf, int length);
+
+// Uart::read()
+
+%typemap(in) (char* data, int length) {
+   if (!PyInt_Check($input)) {
+       PyErr_SetString(PyExc_ValueError, "Expecting an integer");
+       return NULL;
+   }
+   $2 = PyInt_AsLong($input);
+   if ($2 < 0) {
+       PyErr_SetString(PyExc_ValueError, "Positive integer expected");
+       return NULL;
+   }
+   $1 = (char*) malloc($2 * sizeof(char));
+}
+
+%typemap(argout) (char* data, int length) {
+   Py_XDECREF($result);   /* Blow away any previous result */
+   if (result < 0) {      /* Check for I/O error */
+       free($1);
+       PyErr_SetFromErrno(PyExc_IOError);
+       return NULL;
+   }
+   // Append output value $1 to $result
+   $result = PyByteArray_FromStringAndSize((char*) $1, result);
+   free($1);
+}
+
+// I2c::read()
+
+%typemap(in) (uint8_t *data, int length) {
+   if (!PyInt_Check($input)) {
+       PyErr_SetString(PyExc_ValueError, "Expecting an integer");
+       return NULL;
+   }
+   $2 = PyInt_AsLong($input);
+   if ($2 < 0) {
+       PyErr_SetString(PyExc_ValueError, "Positive integer expected");
+       return NULL;
+   }
+   $1 = (uint8_t*) malloc($2 * sizeof(uint8_t));
+}
+
+%typemap(argout) (uint8_t *data, int length) {
+   Py_XDECREF($result);   /* Blow away any previous result */
+   if (result < 0) {      /* Check for I/O error */
+       free($1);
+       PyErr_SetFromErrno(PyExc_IOError);
+       return NULL;
+   }
+   // Append output value $1 to $result
+   $result = PyByteArray_FromStringAndSize((char*) $1, result);
+   free($1);
+}
+
+// Spi::transfer()
+
+%typemap(in) (uint8_t* txBuf, uint8_t* rxBuf, int length) {
+   if (!PyInt_Check($input)) {
+       PyErr_SetString(PyExc_ValueError, "Expecting an integer");
+       return NULL;
+   }
+   $3 = PyInt_AsLong($input);
+   if ($3 < 0) {
+       PyErr_SetString(PyExc_ValueError, "Positive integer expected");
+       return NULL;
+   }
+   $2 = (uint8_t*) malloc($3 * sizeof(uint8_t));
+}
+
+%typemap(argout) (uint8_t* txBuf, uint8_t* rxBuf, int length) {
+   Py_XDECREF($result);   /* Blow away any previous result */
+   if (result != MRAA_SUCCESS) {      /* Check for I/O error */
+       free($2);
+       PyErr_SetFromErrno(PyExc_IOError);
+       return NULL;
+   }
+   $result = PyByteArray_FromStringAndSize((char*) $2, $3);
+   free($2);
+}
+
+%include ../mraa.i
+
+%init %{
+    #include "python/mraapy.h"
+    #include "mraa_lang_func.h"
+    extern mraa_lang_func_t* lang_func;
+    // Initialise python threads, this allows use to grab the GIL when we are
+    // required to do so
+    Py_InitializeEx(0);
+    PyEval_InitThreads();
+    // Add mraa_init() to the module initialisation process and set isr function
+    mraa_result_t res = mraa_init();
+    if (res == MRAA_SUCCESS) {
+        lang_func->python_isr = &mraa_python_isr;
+    }
+    else
+        SWIG_Error(SWIG_RuntimeError, "mraa_init() failed");
+
+%}