Python _ctypes.Array() Examples

def create_remote_array(subtype, len):

    class RemoteArray(_ctypes.Array):
        _length_ = len
        _type_ = subtype

        def __init__(self, addr, target):
            self._base_addr = addr
            self.target = target

        def __getitem__(self, slice):
            if not isinstance(slice, (int, long)):
                raise NotImplementedError("RemoteArray slice __getitem__")
            if slice >= len:
                raise IndexError("Access to {0} for a RemoteArray of size {1}".format(slice, len))
            item_addr = self._base_addr + (ctypes.sizeof(subtype) * slice)

            # TODO: do better ?
            class TST(ctypes.Structure):
                _fields_ = [("TST", subtype)]
            return RemoteStructure.from_structure(TST)(item_addr, target=self.target).TST
    return RemoteArray


# 64bits pointers 

def _handle_field_getattr(self, ftype, fosset, fsize):
        s = self._target.read_memory(self._base_addr + fosset, fsize)
        if ftype in self._field_type_to_remote_type:
            return self._field_type_to_remote_type[ftype].from_buffer_with_target(bytearray(s), target=self._target).value
        if issubclass(ftype, _ctypes._Pointer):  # Pointer
            return RemoteStructurePointer.from_buffer_with_target_and_ptr_type(bytearray(s), target=self._target, ptr_type=ftype)
        if issubclass(ftype, RemotePtr64):  # Pointer to remote64 bits process
            return RemoteStructurePointer64.from_buffer_with_target_and_ptr_type(bytearray(s), target=self._target, ptr_type=ftype)
        if issubclass(ftype, RemoteStructureUnion):  # Structure|Union already transfomed in remote
            return ftype(self._base_addr + fosset, self._target)
        if issubclass(ftype, ctypes.Structure):  # Structure that must be transfomed
            return RemoteStructure.from_structure(ftype)(self._base_addr + fosset, self._target)
        if issubclass(ftype, ctypes.Union):  # Union that must be transfomed
            return RemoteUnion.from_structure(ftype)(self._base_addr + fosset, self._target)
        if issubclass(ftype, _ctypes.Array):  # Arrays
            return create_remote_array(ftype._type_, ftype._length_)(self._base_addr + fosset, self._target)
        # Normal types
        # Follow the ctypes usage: if it's not directly inherited from _SimpleCData
        # We do not apply the .value
        # Seems weird but it's mandatory AND useful :D (in pe_parse)
        if _SimpleCData not in ftype.__bases__:
            return ftype.from_buffer(bytearray(s))
        return ftype.from_buffer(bytearray(s)).value 

def dtype_from_ctypes_type(t):
    """
    Construct a dtype object from a ctypes type
    """
    if issubclass(t, _ctypes.Array):
        return _from_ctypes_array(t)
    elif issubclass(t, _ctypes._Pointer):
        raise TypeError("ctypes pointers have no dtype equivalent")
    elif issubclass(t, _ctypes.Structure):
        return _from_ctypes_structure(t)
    elif issubclass(t, _ctypes.Union):
        return _from_ctypes_union(t)
    elif isinstance(getattr(t, '_type_', None), str):
        return _from_ctypes_scalar(t)
    else:
        raise NotImplementedError(
            "Unknown ctypes type {}".format(t.__name__)) 

def dtype_from_ctypes_type(t):
    """
    Construct a dtype object from a ctypes type
    """
    if issubclass(t, _ctypes.Array):
        return _from_ctypes_array(t)
    elif issubclass(t, _ctypes._Pointer):
        raise TypeError("ctypes pointers have no dtype equivalent")
    elif issubclass(t, _ctypes.Structure):
        return _from_ctypes_structure(t)
    elif issubclass(t, _ctypes.Union):
        return _from_ctypes_union(t)
    elif isinstance(getattr(t, '_type_', None), str):
        return _from_ctypes_scalar(t)
    else:
        raise NotImplementedError(
            "Unknown ctypes type {}".format(t.__name__)) 

def dtype_from_ctypes_type(t):
    """
    Construct a dtype object from a ctypes type
    """
    if issubclass(t, _ctypes.Array):
        return _from_ctypes_array(t)
    elif issubclass(t, _ctypes._Pointer):
        raise TypeError("ctypes pointers have no dtype equivalent")
    elif issubclass(t, _ctypes.Structure):
        return _from_ctypes_structure(t)
    elif issubclass(t, _ctypes.Union):
        return _from_ctypes_union(t)
    elif isinstance(getattr(t, '_type_', None), str):
        return _from_ctypes_scalar(t)
    else:
        raise NotImplementedError(
            "Unknown ctypes type {}".format(t.__name__)) 

def dtype_from_ctypes_type(t):
    """
    Construct a dtype object from a ctypes type
    """
    if issubclass(t, _ctypes.Array):
        return _from_ctypes_array(t)
    elif issubclass(t, _ctypes._Pointer):
        raise TypeError("ctypes pointers have no dtype equivalent")
    elif issubclass(t, _ctypes.Structure):
        return _from_ctypes_structure(t)
    elif issubclass(t, _ctypes.Union):
        return _from_ctypes_union(t)
    elif isinstance(getattr(t, '_type_', None), str):
        return _from_ctypes_scalar(t)
    else:
        raise NotImplementedError(
            "Unknown ctypes type {}".format(t.__name__)) 

def dtype_from_ctypes_type(t):
    """
    Construct a dtype object from a ctypes type
    """
    if issubclass(t, _ctypes.Array):
        return _from_ctypes_array(t)
    elif issubclass(t, _ctypes._Pointer):
        raise TypeError("ctypes pointers have no dtype equivalent")
    elif issubclass(t, _ctypes.Structure):
        return _from_ctypes_structure(t)
    elif issubclass(t, _ctypes.Union):
        return _from_ctypes_union(t)
    elif isinstance(getattr(t, '_type_', None), str):
        return _from_ctypes_scalar(t)
    else:
        raise NotImplementedError(
            "Unknown ctypes type {}".format(t.__name__)) 

def is_array(x):
    return isinstance(x, _ctypes.Array) 

def expect_byte_string(data):
    if not byte_string(data) and not isinstance(data, Array):
        raise TypeError("Only byte strings can be passed to C code") 

def expect_byte_string(data):
    if not byte_string(data) and not isinstance(data, Array):
        raise TypeError("Only byte strings can be passed to C code") 

def expect_byte_string(data):
    if not byte_string(data) and not isinstance(data, Array):
        raise TypeError("Only byte strings can be passed to C code") 

def _handle_field_getattr(self, ftype, fosset, fsize):
        s = self._target.read_memory(self._base_addr + fosset, fsize)
        if ftype in self._field_type_to_remote_type:
            return self._field_type_to_remote_type[ftype].from_buffer_with_target(bytearray(s), target=self._target).value
        if issubclass(ftype, _ctypes._Pointer):  # Pointer
            return RemoteStructurePointer.from_buffer_with_target_and_ptr_type(bytearray(s), target=self._target, ptr_type=ftype)
        if issubclass(ftype, RemotePtr64):  # Pointer to remote64 bits process
            return RemoteStructurePointer64.from_buffer_with_target_and_ptr_type(bytearray(s), target=self._target, ptr_type=ftype)
        if issubclass(ftype, RemotePtr32):  # Pointer to remote32 bits process
            return RemoteStructurePointer32.from_buffer_with_target_and_ptr_type(bytearray(s), target=self._target, ptr_type=ftype)
        if issubclass(ftype, RemoteStructureUnion):  # Structure|Union already transfomed in remote
            return ftype(self._base_addr + fosset, self._target)
        if issubclass(ftype, ctypes.Structure):  # Structure that must be transfomed
            return RemoteStructure.from_structure(ftype)(self._base_addr + fosset, self._target)
        if issubclass(ftype, ctypes.Union):  # Union that must be transfomed
            return RemoteUnion.from_structure(ftype)(self._base_addr + fosset, self._target)
        if issubclass(ftype, _ctypes.Array):  # Arrays
            # if this is a string: just cast the read value to string
            if ftype._type_ == ctypes.c_char: # Use issubclass instead ?
                return s.split("\x00", 1)[0]
            elif ftype._type_ == ctypes.c_wchar: # Use issubclass instead ?
                # Decode from utf16 -> size /=2 | put it in a wchar array | split at the first "\x00"
                return (ftype._type_ * (fsize / 2)).from_buffer_copy(s.decode('utf16'))[:].split("\x00", 1)[0] # Sorry..
            # I am pretty sur something smarter is possible..
            return create_remote_array(ftype._type_, ftype._length_)(self._base_addr + fosset, self._target)
        # Normal types
        # Follow the ctypes usage: if it's not directly inherited from _SimpleCData
        # We do not apply the .value
        # Seems weird but it's mandatory AND useful :D (in pe_parse)
        if _SimpleCData not in ftype.__bases__:
            return ftype.from_buffer(bytearray(s))
        return ftype.from_buffer(bytearray(s)).value 

def create_remote_array(subtype, len):

    class RemoteArray(_ctypes.Array):
        _length_ = len
        _type_ = subtype

        def __init__(self, addr, target):
            self._base_addr = addr
            self.target = target

        def __getitem__(self, slice):
            # import pdb;pdb.set_trace()
            if not isinstance(slice, int_types):
                raise NotImplementedError("RemoteArray slice __getitem__")
            if slice >= len:
                raise IndexError("Access to {0} for a RemoteArray of size {1}".format(slice, len))
            item_addr = self._base_addr + (ctypes.sizeof(subtype) * slice)

            # TODO: do better ?
            class TST(ctypes.Structure):
                _fields_ = [("TST", subtype)]
            return RemoteStructure.from_structure(TST)(item_addr, target=self.target).TST

        def __getslice__(self, start, stop): # Still used even for python 2.7 wtf :F
            stop = min(stop, len)
            start = max(start, 0)
            # dummy implementation
            return [self[i] for i in range(start, stop)]

    return RemoteArray


# 64bits pointers 

def is_array_type(x):
    return issubclass(x, _ctypes.Array) 

def c_uint8_ptr(data):
        if byte_string(data) or isinstance(data, Array):
            return data
        elif isinstance(data, bytearray):
            local_type = c_ubyte * len(data)
            return local_type.from_buffer(data)
        else:
            raise TypeError("Object type %s cannot be passed to C code" % type(data)) 

def c_uint8_ptr(data):
        if isinstance(data, bytearray):
            # This only works for cffi >= 1.7
            return ffi.cast(uint8_t_type, ffi.from_buffer(data))
        elif byte_string(data) or isinstance(data, Array):
            return data
        else:
            raise TypeError("Object type %s cannot be passed to C code" % type(data)) 

def is_array_type(x):
    return issubclass(x, _ctypes.Array) 

def is_array(x):
    return isinstance(x, _ctypes.Array)