[python-win32] How to parse a binary file

[David Ransier]

I've never written a binary parser before, so I'm looking for some starting
point.

I want to read an image file (Sun Raster format: RAS) and parse the included
color map, writing the color map as a text file (possible CSV format).

I can open the file in "rb" mode and read a certain number of bytes. But
when I try to do something with the value, Python complains that it's not in
the correct format.

Here is some sample code for reading the file (Magic is a 4-byte ID that
identifies the file as RAS format.)




import sys

infile =	"TestImage.ras"
try:
	FH = open(infile, 'rb')
except IOError, eStr:
	print "ERROR: Cannot open ", infile, " for reading: ", eStr
	sys.exit()

	Magic = FH.read(4)
	print "Magic:  %d" % (Magic)




I tried coercing Magic to an int, but that didn't help.


Thanks,
David R

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David Ransier
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