On 9/14/07, Ruby Q. [email protected] wrote:
This week’s Ruby Q. is to write a simple utility. Your program should accept
an IP address as a command-line argument and print out the two letter code for
the country that IP is assigned in. You can find a database for the matching
at:http://software77.net/cgi-bin/ip-country/geo-ip.plTo keep the problem interesting though, let’s write our programs with a focus on
speed and memory efficiency.
Hi All,
Here’s my submission. It’s almost exactly the same as Jesus’. I have
a feeling everyone is going to have very similar code for this one.
http://pastie.caboo.se/97332
os = ARGV[0].split(/./)
ip = os[3].to_i + os[2].to_i256 + os[1].to_i2562 + os[0].to_i*2563
f = File.open(“IpToCountry.csv”)
perform binary search on the file
low = 0
high = f.stat.size
while low <= high
mid = (low + high) / 2
f.seek mid # seek to the middle of our search window
f.seek -2, IO::SEEK_CUR until f.getc == ?\n # walk backwards until
we hit a newline
new_high = f.pos - 1
line = f.gets
new_low = f.pos
from, to, x, x, country = line[1…-1].split(/“,”/)
if to.to_i < ip # we are too low, set new low to after this line
low = new_low
elsif from.to_i > ip # we are too high, set new high to before the
last newline
high = new_high
else
puts country; exit
end
end
puts “no country”- steve