Function _ImageHeaderFactory

src/docx/image/image.py:168–182

A |BaseImageHeader| subclass instance that can parse headers of image in `stream`.

(stream: IO[bytes])

def _ImageHeaderFactory(stream: IO[bytes]):
    """A |BaseImageHeader| subclass instance that can parse headers of image in `stream`."""
    from docx.image import SIGNATURES

    def read_32(stream: IO[bytes]):
        stream.seek(0)
        return stream.read(32)

    header = read_32(stream)
    for cls, offset, signature_bytes in SIGNATURES:
        end = offset + len(signature_bytes)
        found_bytes = header[offset:end]
        if found_bytes == signature_bytes:
            return cls.from_stream(stream)
    raise UnrecognizedImageError


class BaseImageHeader: