Hi there,
Im deeply sorry for yet another question to this list. I have come across a
problem to which google seems not
to eager to supply the anwser.
The problem is the following.
First I do this:
def setup_drive():
test = pack('>HH', 0b1000000000000000, 0b1000000100000001)
file = open('drive.bin', 'wb')
for x in range(640000):
file.write(test)
file.close()
I have a pack, which I fill the file with. The data is not of interrest right
now.
This all works great.
Then I do this:
def LoadCommandAndReact(place_to_read):
global RegisterAX
tmp = place_to_read.read()[RegisterAX:calcsize('HH')]
klar = unpack('>HH', tmp)
if place_to_read.closed:
print("Drive error. Drive closed.")
else:
pass
if checkfirstbit(klar[RegisterAX]):
print("First bit is set. Move Cmd.")
if (klar[0] & 0b0111111111111111):
print("Cmd ERROR: Multiple commands is set.")
pass
else:
#Here something to do with mv command.
print("Adress to read to, from the offset of the command")
print(klar[RegisterAX+1]) #Variable is always Offset+1
else:
print("First bit is not set.")
#Change RegisterAX offset+2bytes,
RegisterAX=+2 #We read two bytes per cycle. Becaus command is first, and
variables are second.
This all works If I run the LoadCommand.. only once.
But when I run it for the second time, it complains:
Traceback (most recent call last):
File "core.py", line 98, in <module>
LoadCommandAndReact(readfile)
File "core.py", line 30, in LoadCommandAndReact
klar = unpack('>HH', tmp)
struct.error: unpack requires a string argument of length 4
Im having trouble understanding the error. unpack requires a string argument
of length 4.
I have filled the file with data that should be readable, and is readable by
the function
when I run it for the first time. And since the file is filled with duplicates;
should it not be readable the second
time aswell? I change the RegisterAX =+2. The amount I add should not matter,
Its just my "offset" of where to read in the file.
The problem seems that the second time, unpack doesnt get the size of '>HH' to
read. But surely
.read()[RegisterAX:calcsize('HH')] should assure that its fed with correct
data?
I have filled the file with data of size '>HH' and first command reads that.
So next read should read the next
duplicate of that data that has been written to the file?
I understand its hard to read, and a long email. So well, its just a cry out in
the dark evening. If some one can
share some light.. I would be much happy about it.
/Kent.
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