import mmap
import os


def edit_in_place(path, offset, data):
    """
    Edits a file in-place using mmap
    :param path: Path of file
    :param offset: Start offset
    :param data: Data
    """
    if isinstance(data, str):
        data = data.encode('utf-8')
    mmap_offset = mmap.ALLOCATIONGRANULARITY * (offset // mmap.ALLOCATIONGRANULARITY)
    offset = offset % mmap.ALLOCATIONGRANULARITY
    end = offset + len(data)
    with open(path, 'r+b') as f:
        mm = mmap.mmap(f.fileno(), end, offset=mmap_offset)
        mm[offset:end] = data
        mm.flush()
        mm.close()
        # update modified time of file
        os.utime(f.fileno() if os.utime in os.supports_fd else path)