prasad rao wrote:
hello
I wanted to prevent other users of my computers to read my files.
So tried to creat a module to achieve it.
I used a flag to deside which methods to be called on the object.
somehow it is not working.I realise after 2 days of struggle that
as it is usuel , I am blind to my faults.
I tested all the metheds except main() in idle interactively,found them
working.
So there is a bug in the main(), kan anyone point it out to me?
<code>
#! usr/bin/env python
import ast,random,os,zlib,string
key=5
class Cripto(object):
def __init__(self,afile):
self.afile=afile
def __digi(self,astring):
y=[]
for x in astring:
y.append(ord(x))
y=str(y)
return y
def __undigi(self,astring):
alist=ast.literal_eval(astring)
y=[]
for x in alist:
y.append(chr(x))
astring=''.join(y)
return astring
def __gen_string(self):
s=''
nl=random.sample(string.ascii_letters,key)
for x in nl:s+=x
return s
def __lengthen(self,astring):
s=list(astring)
ns=''
for x in s:
ns+=x
ns+=gen_string()
return ns
def __shorten(self,astring):
s=list(astring)
ns=''
for x in range(0,len(s),key+1):
ns+=s[x]
return ns
def __compress(self,astring):
astring=zlib.compress(astring)
return astring
def __decompress(self,astring):
astring=zlib.decompress(astring)
return astring
def main(self):
sorce=open(self.afile,'r')
data=(sorce.readlines())
dest=open ((os.path.split(self.afile)[0]+os.sep+'temp'),'w')
if data[:1]=='flag1\n':
ns='flag0\n'
data=data[1:]
for line in data:
nl=__compress((__digi(__lengthen(line.strip()))))+'\n'
ns+=nl
dest.write(ns)
elif data[:1]=='flag0\n':
ns='flag1\n'
data=data[1:]
for line in data:
nl=__decompress((__undigi(__shorten(line.strip()))))+'\n'
ns+=nl
dest.write(ns)
sorce.close()
dest.close()
os.remove(self.afile)
os.rename((os.path.split(self.afile)[0]+os.sep+'temp'),self.afile)
#========
a=Cripto('C:/pp.txt')
a.main()
<\code>
First problem is the indentation. It won't compile as it is. I'll
assume that was somehow a pasting error.
Next problem is where you're comparing for 'flag1' Your line if
data[:1] == 'flag1\n' is comparing a list on the left side to a
string on the right. If it were me, I'd replace that test, and the
similar one below it, with
if data[0].rstrip()=='flag1':
The reason for the rstrip() is to make it easier for a test harness,
where it may be a pain to get the newlines on each line. Also, it's
harder to spot a whitespace error.
Next problem/question is whether this is only going to be used for files
that happen to begin with a line flag1. If so, it should be
documented as part of the code, along with all the other missing
documentation/docstrings.
That's as far as I went; I did not test the actual encoding logic But
some free advice for next time: When you ask a question, please
supply a compilable program, and either test data, or enough description
that we can build such. And please tell us what the symptom is.
"it is not working." is not very descriptive.
DaveA
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