Read my first binary file!

Wow.  I am shocked that this worked on the first try.  I created a script to read some of the header information from an S7K file.  One thing that got me stuck for a bit was the fact that the byte order used is little-endian.  Turns out this is no big deal.  I just had to end things with ‘le’, for example s.uintle instead of s.uint.

So here’s my first ever script to read binary data:

[sourcecode language=”python”]
#!usr/bin/env Python

# Purpose: to read the header of an s7k file
# Creator: Michelle

from bitstring import *

s = BitString(filename=’sample.s7k’) # Read in the file sample.s7k, and create a BitString object from it
print s.pos #Print the position in the file.  For fun.

protocolversion = s.readbytes(2).uintle
offset = s.readbytes(2).uintle
syncpat = s.readbytes(4).uintle
size = s.readbytes(4).uintle
print size

odof = s.readbytes(4).uintle
odid = s.readbytes(4).uintle

year = s.readbytes(2).uintle
day = s.readbytes(2).uintle
seconds = s.readbytes(4).floatle
hours = s.readbytes(1).uintle
minutes = s.readbytes(1).uintle

print year,day,seconds,hours,minutes

And the output of my first ever binary-data-reading script:

2009 353 55.1300010681 17 53