Returns size of file, optionally leaving fp positioned at EOF.

def get_cur_file_size(fp, position_to_eof=False):
    """
    Returns size of file, optionally leaving fp positioned at EOF.
    """
    if not position_to_eof:
        cur_pos = fp.tell()
    fp.seek(0, os.SEEK_END)
    cur_file_size = fp.tell()
    if not position_to_eof:
        fp.seek(cur_pos, os.SEEK_SET)
    return cur_file_size