path: root/Objective-C/libffi_support.m

/*
 * Support for libffi (http://sources.redhat.com/libffi)
 *
 * libffi is a library that makes it possible to dynamicly create calls
 * to C functions (without knowing the signature at compile-time). It also
 * provides a way to create closures, that is dynamicly create functions with
 * a runtime specified interface.
 *
 * This file contains functions to dynamicly call objc_msgSendSuper and to
 * dynamicly create IMPs for use in Objective-C method dispatch tables. The
 * file 'register.m' contains compile-time generated equivalents of these.
 */
#include "pyobjc.h"

#import <Foundation/NSHost.h>

#ifdef MACOSX
/*
 * Define SMALL_STRUCT_LIMIT as the largest struct that will be returned
 * in registers instead of with a hidden pointer argument.
 */

#if defined(__ppc__)

#   define SMALL_STRUCT_LIMIT	4

#elif defined(__i386__) 

#   define SMALL_STRUCT_LIMIT 	8

#else

#   error "Unsupported MACOSX platform"

#endif

#endif /* MACOSX */



#ifndef FFI_CLOSURES
#    error "Need FFI_CLOSURES!"
#endif

#if 0 /* Usefull during debugging, only used in the debugger */
static void describe_ffitype(ffi_type* type)
{
	switch (type->type) {
	case FFI_TYPE_VOID: printf("%s", "void"); break;
	case FFI_TYPE_INT: printf("%s", "int"); break;
	case FFI_TYPE_FLOAT: printf("%s", "float"); break;
	case FFI_TYPE_DOUBLE: printf("%s", "double"); break;
	case FFI_TYPE_UINT8: printf("%s", "uint8"); break;
	case FFI_TYPE_SINT8: printf("%s", "sint8"); break;
	case FFI_TYPE_UINT16: printf("%s", "uint16"); break;
	case FFI_TYPE_SINT16: printf("%s", "sint16"); break;
	case FFI_TYPE_UINT32: printf("%s", "uint32"); break;
	case FFI_TYPE_SINT32: printf("%s", "sint32"); break;
	case FFI_TYPE_UINT64: printf("%s", "uint64"); break;
	case FFI_TYPE_SINT64: printf("%s", "sint64"); break;
	case FFI_TYPE_POINTER: printf("%s", "*"); break;
	case FFI_TYPE_STRUCT: {
			ffi_type** elems = type->elements;

			printf("%s", "struct { ");
			if (elems) {
				while (*elems) {
					describe_ffitype(*(elems++));
					printf("%s", "; ");
				}
			}
			printf("%s", "}");
		}
	       break;

	default:
	       // Don't abort, this is called from the debugger 
	       printf("?(%d)", type->type);
	}
}

static void describe_cif(ffi_cif* cif)
{
	size_t i;
	printf("<ffi_cif abi=%d nargs=%d  bytes=%d flags=%#x args=[",
		cif->abi, cif->nargs, cif->bytes, cif->flags);
	for  (i = 0; i < cif->nargs; i++) {
		describe_ffitype(cif->arg_types[i]);
		printf("%s", ", ");
	}
	printf("%s", "] rettype=");
	describe_ffitype(cif->rtype);
	printf("%s", ">\n");
}

#endif

static Py_ssize_t align(Py_ssize_t offset, Py_ssize_t alignment)
{
	Py_ssize_t rest = offset % alignment;
	if (rest == 0) return offset;
	return offset + (alignment - rest);
}

static Py_ssize_t
num_struct_fields(const char* argtype)
{
	Py_ssize_t res = 0;

	if (*argtype != _C_STRUCT_B) return -1;
	while (*argtype != _C_STRUCT_E && *argtype != '=') argtype++;
	if (*argtype == _C_STRUCT_E) return 0;
	
	argtype++;
	while (*argtype != _C_STRUCT_E) {
		argtype = PyObjCRT_SkipTypeSpec(argtype);
		if (argtype == NULL) return -1;
		res ++;
	}
	return res;
}


static void
free_type(void *obj)
{
	PyMem_Free(((ffi_type*)obj)->elements);
	PyMem_Free(obj);
}

static ffi_type* signature_to_ffi_type(const char* argtype);

static ffi_type* 
array_to_ffi_type(const char* argtype)
{
static  PyObject* array_types = NULL; /* XXX: Use NSMap  */
	PyObject* v;
	ffi_type* type;
	Py_ssize_t field_count;
	Py_ssize_t i;
	const char* key = argtype;

	if (array_types == NULL) {
		array_types = PyDict_New();
		if (array_types == NULL) return NULL;
	}

	v = PyDict_GetItemString(array_types, (char*)argtype);
	if (v != NULL) {
		return (ffi_type*)PyCObject_AsVoidPtr(v);
	}

	/* We don't have a type description yet, dynamicly 
	 * create it.
	 */
	field_count = atoi(argtype+1);
			
	type = PyMem_Malloc(sizeof(*type));
	if (type == NULL) {
		PyErr_NoMemory();
		return NULL;
	}
	type->size = PyObjCRT_SizeOfType(argtype);
	type->alignment = PyObjCRT_AlignOfType(argtype);

	/* Libffi doesn't really know about arrays as part of larger 
	 * data-structres (e.g. struct foo { int field[3]; };). We fake it
	 * by treating the nested array as a struct. These seems to work 
	 * fine on MacOS X.
	 */
	type->type = FFI_TYPE_STRUCT;
	type->elements = PyMem_Malloc((1+field_count) * sizeof(ffi_type*));
	if (type->elements == NULL) {
		PyMem_Free(type);
		PyErr_NoMemory();
		return NULL;
	}
	
	while (isdigit(*++argtype));
	type->elements[0] = signature_to_ffi_type(argtype);
	for (i = 1; i < field_count; i++) {
		type->elements[i] = type->elements[0];
	}
	type->elements[field_count] = 0;

	v = PyCObject_FromVoidPtr(type, free_type);
	if (v == NULL) {
		free_type(type);
		return NULL;
	}

	PyDict_SetItemString(array_types, (char*)key, v);
	if (PyErr_Occurred()) {
		Py_DECREF(v);
		return NULL;
	}
	Py_DECREF(v);
	return type;
}

static ffi_type* 
struct_to_ffi_type(const char* argtype)
{
	static  PyObject* struct_types = NULL; /* XXX: Use NSMap  */
	PyObject* v;
	ffi_type* type;
	Py_ssize_t field_count;
	const char* curtype;

	if (struct_types == NULL) {
		struct_types = PyDict_New();
		if (struct_types == NULL) return NULL;
	}

	v = PyDict_GetItemString(struct_types, (char*)argtype);
	if (v != NULL) {
		return (ffi_type*)PyCObject_AsVoidPtr(v);
	}

	/* We don't have a type description yet, dynamicly 
	 * create it.
	 */
	field_count = num_struct_fields(argtype);
	if (field_count == -1) {
		PyErr_Format(PyObjCExc_InternalError,
			"Cannot determine layout of %s", argtype);
		return NULL;
	}
			
	type = PyMem_Malloc(sizeof(*type));
	if (type == NULL) {
		PyErr_NoMemory();
		return NULL;
	}
	type->size = PyObjCRT_SizeOfType(argtype);
	type->alignment = PyObjCRT_AlignOfType(argtype);
	type->type = FFI_TYPE_STRUCT;
	type->elements = PyMem_Malloc((1+field_count) * sizeof(ffi_type*));
	if (type->elements == NULL) {
		PyMem_Free(type);
		PyErr_NoMemory();
		return NULL;
	}
	
	field_count = 0;
	curtype = argtype+1;
	while (*curtype != _C_STRUCT_E && *curtype != '=') curtype++;
	if (*curtype == '=') {
		curtype ++;
		while (*curtype != _C_STRUCT_E) {
			type->elements[field_count] = 
				signature_to_ffi_type(curtype);
			if (type->elements[field_count] == NULL) {
				PyMem_Free(type->elements);
				return NULL;
			}
			field_count++;
			curtype = PyObjCRT_SkipTypeSpec(curtype);
			if (curtype == NULL) {
				PyMem_Free(type->elements);
				return NULL;
			}
		}
	}
	type->elements[field_count] = NULL;

	v = PyCObject_FromVoidPtr(type, free_type);
	if (v == NULL) {
		free_type(type);
		return NULL;
	}

	PyDict_SetItemString(struct_types, (char*)argtype, v);
	if (PyErr_Occurred()) {
		Py_DECREF(v);
		return NULL;
	}
	Py_DECREF(v);
	return type;
}

static ffi_type*
signature_to_ffi_return_type(const char* argtype)
{
	switch (*argtype) {
	case _C_CHR: case _C_SHT:
		return &ffi_type_sint;
	case _C_UCHR: case _C_USHT:
		return &ffi_type_uint;
#ifdef _C_BOOL
	case _C_BOOL: return &ffi_type_sint;
#endif	
	default:
		return signature_to_ffi_type(argtype);
	}
}


static ffi_type*
signature_to_ffi_type(const char* argtype)
{
	switch (*argtype) {
	case _C_VOID: return &ffi_type_void;
	case _C_ID: return &ffi_type_pointer;
	case _C_CLASS: return &ffi_type_pointer;
	case _C_SEL: return &ffi_type_pointer;
	case _C_CHR: return &ffi_type_schar;
#ifdef _C_BOOL
	case _C_BOOL: return &ffi_type_sint;
#endif	
	case _C_UCHR: return &ffi_type_uchar;
	case _C_SHT: return &ffi_type_sshort;
	case _C_USHT: return &ffi_type_ushort;
	case _C_INT: return &ffi_type_sint;
	case _C_UINT: return &ffi_type_uint;

	 /* The next to defintions are incorrect, but the correct definitions
	  * don't work (e.g. give testsuite failures). We should be fine
	  * as long as sizeof(long) == sizeof(int)
	  */
	case _C_LNG: return &ffi_type_sint;  /* ffi_type_slong */
	case _C_ULNG: return &ffi_type_uint;  /* ffi_type_ulong */
	case _C_LNGLNG: return &ffi_type_sint64;
	case _C_ULNGLNG: return &ffi_type_uint64;
	case _C_FLT: return &ffi_type_float;
	case _C_DBL: return &ffi_type_double;
	case _C_CHARPTR: return &ffi_type_pointer;
	case _C_PTR: return &ffi_type_pointer;
	case _C_ARY_B: 
		return array_to_ffi_type(argtype);
	case _C_IN: case _C_OUT: case _C_INOUT: case _C_CONST:
		return signature_to_ffi_type(argtype+1);
	case _C_STRUCT_B: 
		return struct_to_ffi_type(argtype);
	default:
		PyErr_Format(PyExc_NotImplementedError,
			"Type '%#x' not supported", *argtype);
		return NULL;
	}
}

/*
 * arg_signature_to_ffi_type: Make the ffi_type for the call to the method IMP,
 * on MacOS X this is the same as the normal signature_to_ffi_type, but on
 * Linux/GNUstep we need a slightly different function.
 */
#ifdef MACOSX

#ifdef __ppc__
#define arg_signature_to_ffi_type signature_to_ffi_type

#else
static inline ffi_type*
arg_signature_to_ffi_type(const char* argtype)
{
	/* NOTE: This is the minimal change to pass the unittests, it is not
	 * based on analysis of the calling conventions.
	 */
	switch (*argtype) {
	case _C_CHR: return &ffi_type_sint;
	case _C_UCHR: return &ffi_type_uint;
	case _C_SHT: return &ffi_type_sint;
	case _C_USHT: return &ffi_type_uint;
	default: return signature_to_ffi_type(argtype);
	}
}
#endif

#else /* GNUstep */

static inline ffi_type*
arg_signature_to_ffi_type(const char* argtype)
{
	/* NOTE: This is the minimal change to pass the unittests, it is not
	 * based on analysis of the calling conventions.
	 */
	switch (*argtype) {
	case _C_CHR: return &ffi_type_sint;
	case _C_UCHR: return &ffi_type_uint;
	case _C_SHT: return &ffi_type_sint;
	case _C_USHT: return &ffi_type_uint;
	default: return signature_to_ffi_type(argtype);
	}
}

#endif /* GNUstep */

/* This function decodes its arguments into Python values, then
 * calls the python method and finally encodes the return value
 */

typedef struct {
	PyObject* callable;
	PyObjCMethodSignature* methinfo;
} _method_stub_userdata;

static void 
method_stub(ffi_cif* cif __attribute__((__unused__)), void* resp, void** args, void* _userdata)
{
	_method_stub_userdata* userdata = (_method_stub_userdata*)_userdata;
	PyObject* callable = userdata->callable;
	PyObjCMethodSignature* methinfo = userdata->methinfo;
	int isAlloc = 0;
	Py_ssize_t         i;
	PyObject*          arglist;
	PyObject*          res;
	PyObject*          v;
	int                have_output = 0;
	const char*        rettype;
	PyObject* 	   pyself;
	int		   cookie;

	PyGILState_STATE   state = PyGILState_Ensure();

	rettype = methinfo->rettype;

	arglist = PyList_New(0);

	pyself = PyObjCObject_NewTransient(*(id*)args[0], &cookie);
	if (pyself == NULL) {
		goto error;
	}
	if (PyList_Append(arglist, pyself) == -1) {
		goto error;
	}

	/* First translate from Objective-C to python */
	
	for (i = 2; i < methinfo->nargs; i++) {

		const char* argtype = methinfo->argtype[i];

		switch (*argtype) {
		case _C_INOUT: 
			if (argtype[1] == _C_PTR) {
				have_output ++;
			}
			/* FALL THROUGH */
		case _C_IN: case _C_CONST:
			if (argtype[1] == _C_PTR) {
				if (*(void**)args[i]) {
					v = pythonify_c_value(argtype+2, 
						*(void**)args[i]);
				} else {
					v = PyObjC_NULL;
					Py_INCREF(v);
				}
			} else {
				v = pythonify_c_value(argtype+1, 
						args[i]);
			}
			break;
		case _C_OUT:
			/* Skip output parameter */
			if (argtype[1] == _C_PTR) {
				have_output ++;
			}
			continue;
		default:
			v = pythonify_c_value(argtype, args[i]);
		}
		if (v == NULL) {
			Py_DECREF(arglist);
			goto error;
		}
		if (PyList_Append(arglist, v) == -1) {
			Py_DECREF(v);
			Py_DECREF(arglist);
			goto error;
		}
		Py_DECREF(v); 
	}

	v = PyList_AsTuple(arglist);
	if (v == NULL) {
		Py_DECREF(arglist);
		PyObjCObject_ReleaseTransient(pyself, cookie);
		goto error;
	}
	Py_DECREF(arglist);
	arglist = v;

	if (!callable) {
		abort();
	} 

	res = PyObject_Call(callable, arglist, NULL);
	isAlloc = PyObjCSelector_DonatesRef(callable);
	Py_DECREF(arglist);
	PyObjCObject_ReleaseTransient(pyself, cookie);
	if (res == NULL) {
		goto error;
	}

	if (!have_output) {
		int err;

		if (*rettype != _C_VOID) {
			err = depythonify_c_return_value(rettype, res, resp);

			if (isAlloc && *rettype == _C_ID) {
			   /* Must return a 'new' instead of a borrowed 
			    * reference.
			    */
			   [(*(id*)resp) retain];
			} else if (*rettype == _C_ID && res->ob_refcnt == 1) {
				/* make sure return value doesn't die before
				 * the caller can get its hands on it.
				 */
			    [[(*(id*)resp) retain] autorelease];
			}
			Py_DECREF(res);
			if (err == -1) {
				if (res == Py_None) {
					PyErr_Format(PyExc_ValueError,
					   "%s: returned None, expecting "
					   "a value", 
					   PyObjCRT_SELName(*(SEL*)args[1]));
				}
				goto error;
			}
		} else {
			if (res != Py_None) {
				PyErr_Format(PyExc_ValueError,
					"%s: did not return None, expecting "
					"void return value",
					PyObjCRT_SELName(*(SEL*)args[1]));
				goto error;
			}
			*((int*)resp) = 0;
		}
	} else {
		/* We have some output parameters, locate them and encode
		 * their values
		 */
		Py_ssize_t idx;
		PyObject* real_res;

		if (*rettype == _C_VOID && have_output == 1) {
			/* Special case: the python method returned only
			 * the return value, not a tuple.
			 */
			for (i = 2; i < methinfo->nargs; i++) {
				const char* argtype = methinfo->argtype[i];
				int err;

				switch (*argtype) {
				case _C_INOUT: case _C_OUT:
					if (argtype[1] != _C_PTR) {
						continue;
					}
					argtype += 2;
					break;
				default: continue;
				}

				err = depythonify_c_value(argtype, res, *(void**)args[i]);
				if (err == -1) {
					goto error;
				}
				if (res->ob_refcnt == 1 && argtype[0] == _C_ID) {
					/* make sure return value doesn't die before
					 * the caller can get its hands on it.
					 */
					[[**(id**)args[i] retain] autorelease];
				}

				break;
			}

			PyGILState_Release(state);
			return;
		}

		if (*rettype != _C_VOID) {
			if (!PyTuple_Check(res) || PyTuple_Size(res) != have_output+1) {
				PyErr_Format(PyExc_TypeError,
					"%s: Need tuple of %d arguments as result",
					PyObjCRT_SELName(*(SEL*)args[1]), have_output+1);
				Py_DECREF(res);
				goto error;
			}

			real_res = PyTuple_GET_ITEM(res, 0);
			idx = 1;
		} else {
			if (!PyTuple_Check(res) || PyTuple_Size(res) != have_output) {
				PyErr_Format(PyExc_TypeError,
					"%s: Need tuple of %d arguments as result",
					PyObjCRT_SELName(*(SEL*)args[1]), have_output);
				Py_DECREF(res);
				goto error;
			}
			real_res = NULL;
			idx = 0;
		}


		for (i = 2; i < methinfo->nargs; i++) {
			const char* argtype = methinfo->argtype[i];
			int err;

			switch (*argtype) {
			case _C_INOUT: case _C_OUT:
				if (argtype[1] != _C_PTR) {
					continue;
				}
				argtype += 2;
				break;
			default: continue;
			}

			if (*(void**)args[i] != NULL) {
				/* The output pointer might be NULL */

				v = PyTuple_GET_ITEM(res, idx++);
				err = depythonify_c_value(argtype, v, *(void**)args[i]);
				if (err == -1) {
					goto error;
				}
				if (v->ob_refcnt == 1 && argtype[0] == _C_ID) {
					/* make sure return value doesn't die before
					 * the caller can get its hands on it.
					 */
					[[**(id**)args[i] retain] autorelease];
				}
			}
		}

		if (*rettype != _C_VOID) {
			int err = depythonify_c_return_value(rettype, 
				real_res, resp);

			if (isAlloc && *rettype == _C_ID) {
			   /* Must return a 'new' instead of a borrowed 
			    * reference.
			    */
			   [(*(id*)resp) retain];
			} else if (*rettype == _C_ID && real_res->ob_refcnt == 1) {
				/* make sure return value doesn't die before
				 * the caller can get its hands on it.
				 */
			    [[(*(id*)resp) retain] autorelease];
			}
			if (err == -1) {
				if (real_res == Py_None) {
					PyErr_Format(PyExc_ValueError,
					   "%s: returned None, expecting "
					   "a value",
					   PyObjCRT_SELName(*(SEL*)args[1]));
				}
				Py_DECREF(res); 
				goto error;
			}
		} else {
			if (res != Py_None) {
				PyErr_Format(PyExc_ValueError,
					"%s: did not return None, expecting "
					"void return value",
					PyObjCRT_SELName(*(SEL*)args[1]));
				goto error;
			}
			*((int*)resp) = 0;
		}


		Py_DECREF(res);

	}

	PyGILState_Release(state);
	
	return;

error:
	PyObjCErr_ToObjCWithGILState(&state);
}

/* 
 * Return an IMP that is suitable for forwarding a method with the specified
 * signature from Objective-C to Python.
 */
IMP
PyObjCFFI_MakeIMPForSignature(char* signature, PyObject* callable)
{
	_method_stub_userdata* stubUserdata;
	PyObjCMethodSignature* methinfo;
	IMP closure;

	methinfo = PyObjCMethodSignature_FromSignature(signature);
	if (methinfo == NULL) {
		return NULL;
	}

	stubUserdata = PyMem_Malloc(sizeof(*stubUserdata));
	if (stubUserdata == NULL) {
		PyObjCMethodSignature_Free(methinfo);
		return NULL;
	}

	stubUserdata->methinfo = methinfo;

	if (callable) {
		stubUserdata->callable = callable;
		Py_INCREF(stubUserdata->callable);
	} else {
		stubUserdata->callable = NULL;
	}

	closure = PyObjCFFI_MakeClosure(methinfo, method_stub, stubUserdata);
	if (closure == NULL) {
		PyObjCMethodSignature_Free(methinfo);
		if (stubUserdata->callable) {
			Py_DECREF(stubUserdata->callable);
		}
		PyMem_Free(stubUserdata);
		return NULL;
	}

	return closure;
}

IMP
PyObjCFFI_MakeIMPForPyObjCSelector(PyObjCSelector *aSelector) 
{
	if (PyObjCNativeSelector_Check(aSelector)) {
		PyObjCNativeSelector *nativeSelector = 
			(PyObjCNativeSelector *) aSelector;
		PyObjCRT_Method_t aMeth;

		if (nativeSelector->sel_flags & PyObjCSelector_kCLASS_METHOD) {
			aMeth = class_getClassMethod(nativeSelector->sel_class, nativeSelector->sel_selector);
		} else {
			aMeth = class_getInstanceMethod(nativeSelector->sel_class, nativeSelector->sel_selector);
		}
		return aMeth->method_imp;
	} else {
		PyObjCPythonSelector *pythonSelector = (PyObjCPythonSelector *) aSelector;
		return PyObjCFFI_MakeIMPForSignature(pythonSelector->sel_signature, pythonSelector->callable);
	}
}

/* Count the number of arguments and their total size */
/* argument_size is not cleared and should be initialized to the amount of
 * bufferspace that will be allocated just before the argument array
 */
int PyObjCFFI_CountArguments(
		PyObjCMethodSignature* methinfo, Py_ssize_t argOffset,
		Py_ssize_t* byref_in_count, 
		Py_ssize_t* byref_out_count,
		Py_ssize_t* plain_count,
		Py_ssize_t* argbuf_len)
{
	Py_ssize_t i;
	Py_ssize_t itemAlign;
	Py_ssize_t itemSize;

	*byref_in_count = *byref_out_count = *plain_count = 0;
	
	for (i = argOffset; i < methinfo->nargs; i++) {
		const char *argtype = methinfo->argtype[i];

		switch (*argtype) {
		case _C_INOUT:
			if (argtype[1] == _C_PTR) {
				(*byref_out_count) ++;
				(*byref_in_count) ++;
				itemAlign = PyObjCRT_AlignOfType(argtype+2);
				itemSize = PyObjCRT_SizeOfType(argtype+2);
				if (itemSize == -1) {
					return -1;
				}
			} else {
				itemSize = PyObjCRT_SizeOfType(argtype+1);
				itemAlign = PyObjCRT_AlignOfType(argtype+1);
				if (itemSize == -1) {
					return -1;
				}
			}
			*argbuf_len = align(*argbuf_len, itemAlign);
			(*argbuf_len) += itemSize;
			break;

		case _C_IN: case _C_CONST:
			if (argtype[1] == _C_PTR) {
				(*byref_in_count) ++;
				itemSize = PyObjCRT_SizeOfType(argtype+2);
				itemAlign = PyObjCRT_AlignOfType(argtype+2);
				if (itemSize == -1) {
					return -1;
				}
			} else {
				(*plain_count) ++;
				itemSize = PyObjCRT_SizeOfType(argtype+1);
				itemAlign = PyObjCRT_AlignOfType(argtype+1);
				if (itemSize == -1) {
					return -1;
				}
			}
			*argbuf_len = align(*argbuf_len, itemAlign);
			(*argbuf_len) += itemSize;
			break;

		case _C_OUT:
			if (argtype[1] == _C_PTR) {
				(*byref_out_count) ++;
				itemSize = PyObjCRT_SizeOfType(argtype+2);
				itemAlign = PyObjCRT_AlignOfType(argtype+2);
				if (itemSize == -1) {
					return -1;
				}
			} else {
				(*plain_count)++;
				itemSize = PyObjCRT_SizeOfType(argtype+1);
				itemAlign = PyObjCRT_AlignOfType(argtype+1);
				if (itemSize == -1) {
					return -1;
				}
			}
			*argbuf_len = align(*argbuf_len, itemAlign);
			(*argbuf_len) += itemSize;
			break;

		case _C_STRUCT_B: case _C_UNION_B: case _C_ARY_B:
			(*plain_count)++;
			itemSize = PyObjCRT_SizeOfType(argtype);
			itemAlign = PyObjCRT_AlignOfType(argtype);
			if (itemSize == -1) {
				return -1;
			}
			*argbuf_len = align(*argbuf_len, itemAlign);
			(*argbuf_len) += itemSize;
			break;

		default:
			itemSize = PyObjCRT_SizeOfType(argtype);
			itemAlign = PyObjCRT_AlignOfType(argtype);
			if (itemSize == -1) {
				return -1;
			}
			*argbuf_len = align(*argbuf_len, itemAlign);
			(*argbuf_len) += itemSize;
			(*plain_count)++;
			break;
		}
	}
	return 0;
}

int PyObjCFFI_ParseArguments(
		PyObjCMethodSignature* methinfo, Py_ssize_t argOffset,
		PyObject* args,
		Py_ssize_t argbuf_cur, unsigned char* argbuf,
		void** byref,
		ffi_type** arglist, void** values)
{
	Py_ssize_t py_arg = 0;
	Py_ssize_t i;
	void* arg;

	for (i = argOffset; i < methinfo->nargs; i++) {

		int error;
		PyObject *argument;
		const char *argtype = methinfo->argtype[i];

		if (argtype[0] == _C_OUT && argtype[1] == _C_PTR) {
			/* Just allocate room in argbuf and set that*/
			Py_ssize_t sz;

			argbuf_cur = align(argbuf_cur, 
				PyObjCRT_AlignOfType(argtype+2));
			arg = argbuf + argbuf_cur;
			byref[i] = arg;

			arglist[i] = &ffi_type_pointer;
			values[i] = byref+i;

			sz = PyObjCRT_SizeOfType(argtype+2);
			argbuf_cur += sz;

			/* Clear the output buffer, just in case the called
			 * function doesn't write anything into the buffer.
			 */
			memset(arg, 0, sz);
		} else {
			/* Encode argument, maybe after allocating space */

			if (argtype[0] == _C_OUT) argtype ++;

			argument = PyTuple_GET_ITEM (args, py_arg);
			switch (*argtype) {
			case _C_STRUCT_B: case _C_ARY_B: case _C_UNION_B:
				/* Allocate space and encode */
				argbuf_cur = align(argbuf_cur, 
					PyObjCRT_AlignOfType(argtype));
				arg = argbuf + argbuf_cur;
				argbuf_cur += PyObjCRT_SizeOfType(argtype);
				byref[i] = arg;
				error = depythonify_c_value (
					argtype, 
					argument, 
					arg);

				arglist[i] = signature_to_ffi_type(argtype);
				values[i] = arg;
				break;
			case _C_INOUT:
			case _C_IN:
			case _C_CONST:

				if (argtype[1] == _C_PTR) {
					/* Allocate space and encode */

					if (argument == PyObjC_NULL) {
						byref[i] = NULL;
						error = 0;

					} else {
						argbuf_cur = align(argbuf_cur, PyObjCRT_AlignOfType(argtype+2)); 
						arg = argbuf + argbuf_cur;
						argbuf_cur += PyObjCRT_SizeOfType(argtype+2);
						byref[i] = arg;
						error = depythonify_c_value (
							argtype+2, 
							argument, 
							arg);
					}

					arglist[i] = &ffi_type_pointer;
					values[i] = byref + i;

				} else {
					/* just encode */
					argbuf_cur = align(argbuf_cur, PyObjCRT_AlignOfType(argtype+1));
					arg = argbuf + argbuf_cur;
					argbuf_cur += PyObjCRT_SizeOfType(argtype+1);
	  				error = depythonify_c_value (
						argtype+1, 
						argument, 
						arg);

					arglist[i] = signature_to_ffi_type(
						argtype+1);
					values[i] = arg;

				}
				break;
			default:
				argbuf_cur = align(argbuf_cur, PyObjCRT_AlignOfType(argtype));
				arg = argbuf + argbuf_cur;
				argbuf_cur += PyObjCRT_SizeOfType(argtype);

	  			error = depythonify_c_value (
					argtype, 
					argument, 
					arg);

				arglist[i] = signature_to_ffi_type(argtype);
				values[i] = arg;
			}

			if (error == -1) {
				return -1;
			}
			py_arg++;
		}
	}
	return 0;
}

/* XXX: Need to refactor to deal with 'self' */
{
	PyObject* objc_result = NULL;
	PyObject* result = NULL;
	int py_arg;
	void* arg;
	Py_ssize_t i;

	if ( (*methinfo->rettype != _C_VOID) /* && ([methinfo isOneway] == NO) */ ) {
		objc_result = pythonify_c_return_value (methinfo->rettype, pRetval);
	} else {
		Py_INCREF(Py_None);
		objc_result =  Py_None;
	}

	/* XXX: This is for selectors only, need to change this !!!! */

	if (self != NULL && objc_result != self
		&& PyObjCObject_Check(self) && PyObjCObject_Check(objc_result)
		&& !(flags & PyObjCSelector_kRETURNS_UNINITIALIZED)
		&& (((PyObjCObject*)self)->flags & PyObjCObject_kUNINITIALIZED)) {
		[PyObjCObject_GetObject(objc_result) release];
		PyObjCObject_ClearObject(self);
	}

	if (byref_out_count == 0) {
		return objc_result;

	} else {

		if (*methinfo->rettype == _C_VOID) {
			if (byref_out_count > 1) {
				result = PyTuple_New(byref_out_count);
				if (result == NULL) {
					return NULL;
				}
			} else {
				result = NULL;
			}
			Py_DECREF(objc_result);
			py_arg = 0;
		} else {
			result = PyTuple_New(byref_out_count+1);
			if (result == NULL) {
				return NULL;
			}
			PyTuple_SET_ITEM(result, 0, objc_result);
			py_arg = 1;
		}
		objc_result = NULL;

		for (i = argOffset; i < methinfo->nargs; i++) {
			const char *argtype = methinfo->argtype[i];
			PyObject*   v;

			switch (*argtype) {
			case _C_INOUT:
			case _C_OUT:
				if (argtype[1] == _C_PTR) {
					arg = byref[i];

					if (arg == NULL) {
						v = PyObjC_NULL;
						Py_INCREF(v);
					} else {
						v = pythonify_c_value(argtype+2, arg);
					}
					if (!v) goto error_cleanup;

					if (result != NULL) {
						if (PyTuple_SetItem(result, 
							py_arg++, v) < 0) {

							Py_DECREF(v);
							goto error_cleanup;
						}
					} else {
						result = v;
					}
				}
				break;
			}
		}
	}
	return result;

error_cleanup:
	Py_XDECREF(result);
	return NULL;
}