"Sergey Dorofeev" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
>I can use string.unpack if string in struct uses fixed amount of bytes.
I presume you mean struct.unpack(format, string). The string len must be
known when you call, but need not be fixed across multiple calls with
different strings.
> But is there some extension to struct modue, which allows to unpack
> zero-terminated string, size of which is unknown?
> E.g. such struct: long, long, some bytes (string), zero, short,
> short,short.
Size is easy to determine. Given the above and string s (untested code):
prelen = struct.calcsize('2l')
strlen = s.find('\0', prelen) - prelen
format = '2l %ds h c 3h' % strlen # c swallows null byte
Note that C structs can have only one variable-sized field and only at the
end. With that restriction, one could slice and unpack the fixed stuff and
then directly slice out the end string. (Again, untested)
format = 2l 3h' # for instance
prelen = struct.calcsize(format)
tup = struct.unpack(format, s[:prelen])
varstr = s[prelen, -1] # -1 chops off null byte
Terry J. Reedy
--
http://mail.python.org/mailman/listinfo/python-list
