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Testing tool: corrupt a file
#!/usr/bin/env python -u
# Read from stdin, corrupt/remove random bytes, write to standard out.
import optparse
import random
import sys
def main():
parser = optparse.OptionParser(usage="%prog [options]")
parser.add_option("--n", dest="n", type="int", default=1,
help="how many single-byte errors to introduce")
parser.add_option("--r", dest="remove", type="int", default=0,
help="how many bytes to erase")
parser.add_option("--verbose", dest="verbose", action="store_true",
help="be verbose")
(options, args) = parser.parse_args()
data = bytearray(sys.stdin.read())
for i in range(0, options.n):
position = random.randrange(0, len(data))
oldbyte = data[position]
newbyte = (oldbyte+random.randrange(1,256))%256
data[position] = newbyte
if options.verbose:
print >> sys.stderr, "Replaced byte %d with %d at position %d"%(oldbyte,newbyte,position)
for i in range(0, options.remove):
position = random.randrange(0, len(data))
oldbyte = data[position]
del data[position]
if options.verbose:
print >> sys.stderr, "Deleted byte at position %d"%(position)
sys.stdout.write(data)
if __name__ == '__main__':
main()
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