bluefile.py 文件源码

def pack_ext_header(hdr, structured=0):
    """
    Packs the value of the given BLUE file hdr dictionary's
    'ext_header' key into the BLUE file extended header format and
    updates the value of 'ext_size'.  The value of 'ext_header' can be
    a list of (key, value) tuples or a dict.  Before writing this out
    to disk at the end of a BLUE file it must be padded out to a
    multiple of 512 bytes.  If the keywords given are already a string
    it is presumed they are already packed and the 'ext_size' field is
    updated but the string itself is left alone.

    If <structured> is true, any embedded Python dictionaries, lists
    or tuples will pack their structure into the keywords with
    them. See pack_keywords() for more info.
    """
    packed = pack_keywords(hdr['ext_header'], _rep_tran[hdr['head_rep']],
                           structured=structured)
    hdr['ext_header'] = packed
    hdr['ext_size'] = len(packed)