[Tutor] reading binary file on windows and linux

[Jan Jansen]

Hello,

I've got some trouble reading binary files with struct.unpack on windows.
According to the documentation of the binary file's content, at the
beginning there're some simple bytes (labeled as 'UChar: 8-bit unsigned
byte'). Within those bytes there's a sequence to check the file's sanity.
The sequence is (in ascii C-Notation):
" "
"\n"
"\r"
"\n"
" "
I've downloaded the file from the same website from two machines. One is a
Windows 7 64-Bit, the other one is a virtual Linux machine. Now the trouble
is while on linux everything is fine, on windows the carriage return does
not appear when reading the file with struct.unpack.

The file sizes on Linux and Windows are exaktly the same, and also my script
determines the file sizes correctly on both plattforms (according to the
OS). When I open the file on Windows in an editor and display the
whitespaces, the linefeed and cariage-return are shown a expected.

The code I'm using to check the first 80 bytes of the file is:

import struct
import sys

with open(sys.argv[1]) as source:
    size = struct.calcsize("80B")
    raw_data = struct.unpack("80B", source.read(size))
    for i, data in enumerate(raw_data):
        print i, data, chr(data)
    source.seek(0, 2)
    print source.tell()


Any suggestions are highly appreciated.

Cheers,

Jan
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