gaviota.py 文件源码

def open_tablebases(directory=None, libgtb=None, LibraryLoader=ctypes.cdll):
    """
    Opens a collection of tablebases for probing.

    First native access via the shared library libgtb is tried. You can
    optionally provide a specific library name or a library loader.
    The shared library has global state and caches, so only one instance can
    be open at a time.

    Second pure Python probing code is tried.
    """
    try:
        if LibraryLoader:
            return open_tablebases_native(directory, libgtb, LibraryLoader)
    except (OSError, RuntimeError) as err:
        LOGGER.info("Falling back to pure Python tablebases: %r", err)

    try:
        import lzma
    except ImportError:
        try:
            from backports import lzma
        except ImportError:
            LOGGER.exception("You should install backports.lzma")

    return PythonTablebases(directory, lzma)