Building a string with var = var .. "something" has miserable time
complexities. This commit cleans up a lot of that in scripts, focusing
on packing of data with bin.pack and concatenations within loops.
Additionally, a few instances were replaced with string.rep
Changes fall into these categories:
1. Avoid pathological string building. Loops over x = x .. "foo" can
become very slow. Instead, use strbuf.lua, table.concat, or just one
continuous concatenation; a = x .. y .. z is one operation, better than
a = x .. y; a = a .. z
2. Use hex-escaped strings instead of string.char. I find this more
readable in many cases, and it avoids a table lookup and function call.
3. Don't duplicate code. A few libraries and scripts had re-implemented
stdnse.generate_random_string or openssl.rand_bytes.
This is a maintenance fix for the NSE Nsock library binding. The patch focuses
on code correctness and simplicity. The patch also brings some initial updates
with an eye towards the upcoming Lua 5.2 release. See [1] for a post concerning
this branch.
[1] http://seclists.org/nmap-dev/2010/q3/710
discussion on nmap-dev about how best to handle these. I also updated the docs and
am about to regenerate script.db. See this thread for more info:
http://seclists.org/nmap-dev/2009/q3/1008.html
with the struct (bin) library available:
function hextobin(str) return bin.pack("H", str) end
function bintohex(str) return bin.unpack("H", str) end
Also removed a commented copy that was in the sniffer-detect.nse script.
