Python ctypes.memset() Examples

def zerome(bufferObject):
    '''
    clear a string value from memory

    :param bufferObject: the string variable, which should be cleared
    :type  bufferObject: string or key buffer

    :return:    - nothing -
    '''
    data = ctypes.POINTER(ctypes.c_char)()
    size = ctypes.c_int()  # Note, int only valid for python 2.5
    ctypes.pythonapi.PyObject_AsCharBuffer(ctypes.py_object(bufferObject),
                                           ctypes.pointer(data),
                                           ctypes.pointer(size))
    ctypes.memset(data, 0, size.value)

    return 

def fill( rgn, length=None, offset=0, value=0 ):
        if value not in range(256):
            raise ValueError( "invalid fill value" )
        if length is None:
            length = rgn.mappable
        # map ctypes instance (does all necessary error checking)
        mem = (ubyte * length).from_buffer( rgn._mmap, offset )
        ctypes.memset( mem, value, length )

    # write data into region at given offset 

def memset(self, allocation, value, size):
        """set the memory in allocation to the value in value

        :param allocation: An Argument for some memory allocation unit
        :type allocation: Argument

        :param value: The value to set the memory to
        :type value: a single 8-bit unsigned int

        :param size: The size of to the allocation unit in bytes
        :type size: int
        """
        C.memset(allocation.ctypes, value, size) 

def add_dline(buf: ctypes.Array, cell_width: int, position: int, thickness: int, cell_height: int) -> None:
    a = min(position - thickness, cell_height - 1)
    b = min(position, cell_height - 1)
    top, bottom = min(a, b), max(a, b)
    deficit = 2 - (bottom - top)
    if deficit > 0:
        if bottom + deficit < cell_height:
            bottom += deficit
        elif bottom < cell_height - 1:
            bottom += 1
            if deficit > 1:
                top -= deficit - 1
        else:
            top -= deficit
    top = max(0, min(top, cell_height - 1))
    bottom = max(0, min(bottom, cell_height - 1))
    for y in {top, bottom}:
        ctypes.memset(ctypes.addressof(buf) + (cell_width * y), 255, cell_width) 

def RawValue(typecode_or_type, *args):
    '''
    Returns a ctypes object allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    obj = _new_value(type_)
    ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
    obj.__init__(*args)
    return obj 

def RawArray(typecode_or_type, size_or_initializer):
    '''
    Returns a ctypes array allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    if isinstance(size_or_initializer, (int, long)):
        type_ = type_ * size_or_initializer
        obj = _new_value(type_)
        ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
        return obj
    else:
        type_ = type_ * len(size_or_initializer)
        result = _new_value(type_)
        result.__init__(*size_or_initializer)
        return result 

def RawArray(typecode_or_type, size_or_initializer):
    '''
    Returns a ctypes array allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    if isinstance(size_or_initializer, int):
        type_ = type_ * size_or_initializer
        obj = _new_value(type_)
        ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
        return obj
    else:
        type_ = type_ * len(size_or_initializer)
        result = _new_value(type_)
        result.__init__(*size_or_initializer)
        return result 

def memset(self, offset: int, value: int, size: int) -> int:
        # self.asan_raw(offset, size) -> pasted here for speed
        if offset > self.__size or offset + size > self.__size:
            raise MemoryError(
                f'Not enough memory (tried to write to address range '
                f'0x{offset:08x}-0x{offset + size:08x} ({size} bytes), maximum address: 0x{self.size:08x} bytes)'
            )

        assert offset >= 0, f'Invalid memory address: {hex(offset)}'

        return memset(self.base + offset, value, size) - self.base

    # def set_addr(self, offset: int, size: int, addr: int) -> None:
    #     memmove(self.base + offset, addr, size) 

def add_line(buf: ctypes.Array, cell_width: int, position: int, thickness: int, cell_height: int) -> None:
    y = position - thickness // 2
    while thickness > 0 and -1 < y < cell_height:
        thickness -= 1
        ctypes.memset(ctypes.addressof(buf) + (cell_width * y), 255, cell_width)
        y += 1 

def filled_buffer(audio_format, buffer_):
    pointer = buffer_.lock(0, 1024)
    if audio_format.sample_size == 8:
        c = 0x80
    else:
        c = 0x00
    ctypes.memset(pointer.audio_ptr_1, c, pointer.audio_length_1.value)
    if pointer.audio_length_2.value > 0:
        ctypes.memset(pointer.audio_ptr_2, c, pointer.audio_length_2.value)

    return buffer_ 

def write(self, audio_data, length):
        # Pass audio_data=None to write silence
        if length == 0:
            return 0

        write_ptr = self._ds_buffer.lock(self._write_cursor_ring, length)
        assert 0 < length <= self._buffer_size
        assert length == write_ptr.audio_length_1.value + write_ptr.audio_length_2.value

        if audio_data:
            ctypes.memmove(write_ptr.audio_ptr_1, audio_data.data, write_ptr.audio_length_1.value)
            audio_data.consume(write_ptr.audio_length_1.value, self.source.audio_format)
            if write_ptr.audio_length_2.value > 0:
                ctypes.memmove(write_ptr.audio_ptr_2, audio_data.data, write_ptr.audio_length_2.value)
                audio_data.consume(write_ptr.audio_length_2.value, self.source.audio_format)
        else:
            if self.source.audio_format.sample_size == 8:
                c = 0x80
            else:
                c = 0
            ctypes.memset(write_ptr.audio_ptr_1, c, write_ptr.audio_length_1.value)
            if write_ptr.audio_length_2.value > 0:
                ctypes.memset(write_ptr.audio_ptr_2, c, write_ptr.audio_length_2.value)
        self._ds_buffer.unlock(write_ptr)

        self._write_cursor += length
        self._write_cursor_ring += length
        self._write_cursor_ring %= self._buffer_size 

def _win32_load_kernel (self):
		if self.unix:
			return False
		import ctypes
		if not self.kernel32:
			self.kernel32 = ctypes.windll.LoadLibrary("kernel32.dll")
		if not self.textdata:
			self.textdata = ctypes.create_string_buffer('0' * 2048)
		ctypes.memset(self.textdata, 0, 2048)
		return True 

def fgetattr(self, path, buf, fip):
        ctypes.memset(buf, 0, ctypes.sizeof(c_stat))

        st = buf.contents
        if not fip:
            fh = fip
        elif self.raw_fi:
            fh = fip.contents
        else:
            fh = fip.contents.fh

        attrs = self.operations('getattr', self._decode_optional_path(path), fh)
        set_st_attrs(st, attrs, use_ns=self.use_ns)
        return 0 

def RawValue(typecode_or_type, *args):
    '''
    Returns a ctypes object allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    obj = _new_value(type_)
    ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
    obj.__init__(*args)
    return obj 

def RawArray(typecode_or_type, size_or_initializer):
    '''
    Returns a ctypes array allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    if isinstance(size_or_initializer, (int, long)):
        type_ = type_ * size_or_initializer
        obj = _new_value(type_)
        ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
        return obj
    else:
        type_ = type_ * len(size_or_initializer)
        result = _new_value(type_)
        result.__init__(*size_or_initializer)
        return result 

def RawValue(typecode_or_type, *args):
    '''
    Returns a ctypes object allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    obj = _new_value(type_)
    ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
    obj.__init__(*args)
    return obj 

def RawArray(typecode_or_type, size_or_initializer):
    '''
    Returns a ctypes array allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    if isinstance(size_or_initializer, int):
        type_ = type_ * size_or_initializer
        obj = _new_value(type_)
        ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
        return obj
    else:
        type_ = type_ * len(size_or_initializer)
        result = _new_value(type_)
        result.__init__(*size_or_initializer)
        return result 

def create(cls):
        buff = windows.utils.BUFFER(cls)(size=cls.FULL_SIZE)
        # ctypes.memset(buff, "\x00", cls.FULL_SIZE)
        self = buff[0]
        self.Wnode.BufferSize = cls.FULL_SIZE
        self.LoggerNameOffset = ctypes.sizeof(cls)
        self.LogFileNameOffset = ctypes.sizeof(cls) + MAX_SESSION_NAME_LEN
        return self 

def RawValue(typecode_or_type, *args):
    '''
    Returns a ctypes object allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    obj = _new_value(type_)
    ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
    obj.__init__(*args)
    return obj 

def RawArray(typecode_or_type, size_or_initializer):
    '''
    Returns a ctypes array allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    if isinstance(size_or_initializer, (int, long)):
        type_ = type_ * size_or_initializer
        obj = _new_value(type_)
        ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
        return obj
    else:
        type_ = type_ * len(size_or_initializer)
        result = _new_value(type_)
        result.__init__(*size_or_initializer)
        return result 

def RawValue(typecode_or_type, *args):
    '''
    Returns a ctypes object allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    obj = _new_value(type_)
    ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
    obj.__init__(*args)
    return obj 

def ioctl(self, driver_handle: ctypes.c_void_p, ioctl_code: ctypes.c_ulong, input_bytes: ctypes.c_void_p, input_bytes_count: ctypes.c_size_t, output_bytes: ctypes.c_void_p, output_bytes_count: ctypes.c_size_t):
        """ Wrapper for DeviceIoControl """
        overlapped = self.libk.OVERLAPPED()
        ctypes.memset(ctypes.addressof(overlapped), 0, ctypes.sizeof(overlapped))

        ret = ctypes.windll.kernel32.DeviceIoControl(driver_handle, ioctl_code, input_bytes, input_bytes_count, output_bytes, output_bytes_count, None, ctypes.byref(overlapped))

        # We expect this to error, which matches the others ^_^
        if ret == False:
            raise ctypes.WinError() 

def RawArray(typecode_or_type, size_or_initializer):
    '''
    Returns a ctypes array allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    if isinstance(size_or_initializer, (int, long)):
        type_ = type_ * size_or_initializer
        obj = _new_value(type_)
        ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
        return obj
    else:
        type_ = type_ * len(size_or_initializer)
        result = _new_value(type_)
        result.__init__(*size_or_initializer)
        return result 

def _set_argv(process_name: str) -> None:
  """
  Overwrites our argv in a similar fashion to how it's done in C with:
  strcpy(argv[0], 'new_name');
  """

  if Py_GetArgcArgv is None:
    return

  global _PROCESS_NAME

  # both gets the current process name and initializes _MAX_NAME_LENGTH

  current_name = get_process_name()

  argv, argc = ctypes.c_int(0), argc_t()
  Py_GetArgcArgv(argv, ctypes.pointer(argc))

  if len(process_name) > _MAX_NAME_LENGTH:
    raise IOError("Can't rename process to something longer than our initial name (this would overwrite memory used for the env)")

  # space we need to clear
  zero_size = max(len(current_name), len(process_name))

  ctypes.memset(argc.contents, 0, zero_size + 1)  # null terminate the string's end
  process_name_encoded = process_name.encode('utf8')
  ctypes.memmove(argc.contents, process_name_encoded, len(process_name))
  _PROCESS_NAME = process_name 

def RawValue(typecode_or_type, *args):
    '''
    Returns a ctypes object allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    obj = _new_value(type_)
    ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
    obj.__init__(*args)
    return obj 

def RawArray(typecode_or_type, size_or_initializer):
    '''
    Returns a ctypes array allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    if isinstance(size_or_initializer, (int, long)):
        type_ = type_ * size_or_initializer
        obj = _new_value(type_)
        ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
        return obj
    else:
        type_ = type_ * len(size_or_initializer)
        result = _new_value(type_)
        result.__init__(*size_or_initializer)
        return result 

def _win32_load_kernel (self):
		if self.unix:
			return False
		import ctypes
		if not self.kernel32:
			self.kernel32 = ctypes.windll.LoadLibrary("kernel32.dll")
		if not self.textdata:
			self.textdata = ctypes.create_string_buffer('0' * 2048)
		ctypes.memset(self.textdata, 0, 2048)
		return True 

def RawValue(typecode_or_type, *args):
    '''
    Returns a ctypes object allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    obj = _new_value(type_)
    ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
    obj.__init__(*args)
    return obj 

def RawArray(typecode_or_type, size_or_initializer):
    '''
    Returns a ctypes array allocated from shared memory
    '''
    type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
    if isinstance(size_or_initializer, (int, long)):
        type_ = type_ * size_or_initializer
        obj = _new_value(type_)
        ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
        return obj
    else:
        type_ = type_ * len(size_or_initializer)
        result = _new_value(type_)
        result.__init__(*size_or_initializer)
        return result 

def segfault():
    """this will segfault"""
    import ctypes
    ctypes.memset(-1,0,1)