Problem reading/writing files

[faulkner]

have you been using text mode?

smeenehan at hmc.edu wrote:
> This is a bit of a peculiar problem. First off, this relates to Python
> Challenge #12, so if you are attempting those and have yet to finish
> #12, as there are potential spoilers here.
>
> I have five different image files shuffled up in one big binary file.
> In order to view them I have to "unshuffle" the data, which means
> moving bytes around. Currently my approach is to read the data from the
> original, unshuffle as necessary, and then write to 5 different files
> (2 .jpgs, 2 .pngs and 1 .gif).
>
> The problem is with the read() method. If I read a byte valued as 0x00
> (in hexadecimal), the read method returns a character with the value
> 0x20. When printed as strings, these two values look the same (null and
> space, respectively), but obviously this screws with the data and makes
> the resulting image file unreadable. I can add a simple if statement to
> correct this, which seems to make the .jpgs readable, but the .pngs
> still have errors and the .gif is corrupted, which makes me wonder if
> the read method is not doing this to other bytes as well.
>
> Now, the *really* peculiar thing is that I made a simple little file
> and used my hex editor to manually change the first byte to 0x00. When
> I read that byte with the read() method, it returned the correct value,
> which boggles me.
>
> Anyone have any idea what could be going on? Alternatively, is there a
> better way to shift about bytes in a non-text file without using the
> read() method (since returning the byte as a string seems to be what's
> causing the issue)? Thanks in advance!