| import cython |
| from cython.cimports.cpython import PyBUF_WRITABLE, PyBuffer_FillInfo |
| from cython.cimports.cpython.buffer import ( |
| PyBUF_SIMPLE, |
| PyBuffer_Release, |
| PyObject_CheckBuffer, |
| PyObject_GetBuffer, |
| ) |
| from cython.cimports.libc.string import memcpy |
|
|
|
|
| @cython.cclass |
| class ByteSource: |
| def __cinit__(self, owner): |
| self.owner = owner |
|
|
| try: |
| self.ptr = owner |
| except TypeError: |
| pass |
| else: |
| self.length = len(owner) |
| return |
|
|
| if PyObject_CheckBuffer(owner): |
| |
| res = PyObject_GetBuffer(owner, cython.address(self.view), PyBUF_SIMPLE) |
| if not res: |
| self.has_view = True |
| self.ptr = cython.cast(cython.p_uchar, self.view.buf) |
| self.length = self.view.len |
| return |
|
|
| raise TypeError("expected bytes, bytearray or memoryview") |
|
|
| def __dealloc__(self): |
| if self.has_view: |
| PyBuffer_Release(cython.address(self.view)) |
|
|
|
|
| @cython.cfunc |
| def bytesource(obj, allow_none: cython.bint = False) -> ByteSource | None: |
| if allow_none and obj is None: |
| return None |
| elif isinstance(obj, ByteSource): |
| return obj |
| else: |
| return ByteSource(obj) |
|
|
|
|
| @cython.cclass |
| class Buffer: |
| """A base class for PyAV objects which support the buffer protocol, such |
| as :class:`.Packet` and :class:`.Plane`. |
| |
| """ |
|
|
| @cython.cfunc |
| def _buffer_size(self) -> cython.size_t: |
| return 0 |
|
|
| def _buffer_ptr(self) -> cython.p_void: |
| return cython.NULL |
|
|
| def _buffer_writable(self) -> cython.bint: |
| return True |
|
|
| def __getbuffer__(self, view: cython.pointer[Py_buffer], flags: cython.int): |
| if flags & PyBUF_WRITABLE and not self._buffer_writable(): |
| raise ValueError("buffer is not writable") |
|
|
| PyBuffer_FillInfo(view, self, self._buffer_ptr(), self._buffer_size(), 0, flags) |
|
|
| @property |
| def buffer_size(self): |
| return self._buffer_size() |
|
|
| @property |
| def buffer_ptr(self): |
| """The memory address of the buffer.""" |
| return cython.cast(cython.size_t, self._buffer_ptr()) |
|
|
| def update(self, input): |
| """Replace the data in this object with the given buffer. |
| |
| Accepts anything that supports the `buffer protocol <https://docs.python.org/3/c-api/buffer.html>`_, |
| e.g. bytes, NumPy arrays, other :class:`Buffer` objects, etc.. |
| |
| """ |
| if not self._buffer_writable(): |
| raise ValueError("buffer is not writable") |
|
|
| source: ByteSource = bytesource(input) |
| size: cython.size_t = self._buffer_size() |
|
|
| if source.length != size: |
| raise ValueError(f"got {source.length} bytes; need {size} bytes") |
|
|
| memcpy(self._buffer_ptr(), source.ptr, size) |
|
|
