turn a service_fp blob into binary blob

service_fp.nse

local lpeg = require "lpeg"
local U = require "lpeg-utility"

local getquote = U.escaped_quote()                                                  
local unescape = lpeg.P ( {
  lpeg.Cs((lpeg.V "simple_char" + lpeg.V "unesc")^0),
  esc = lpeg.P "\\",
  simple_char = lpeg.P(1) - lpeg.V "esc",                                           
  unesc = (lpeg.V "esc" * lpeg.Cs( lpeg.V "esc" + lpeg.V "specials" + lpeg.V "code" + lpeg.P(1) ))/"%1",
  specials = lpeg.S "trn0" / {t="\t", r="\r", n="\n", ["0"]="\0"},                  
  code = (lpeg.P "x" * lpeg.C(lpeg.S "0123456789abcdefABCDEF"^-2))/function(c)
  return string.char(tonumber(c,16)) end,                                           
})  
    
local function getrequest_response (fp)
  fp = string.gsub(fp, "\nSF:", "") 
  stdnse.debug1("fp = >%s<", fp)
  local i, e = string.find(fp, "GetRequest,%d+,")                                   
  stdnse.debug1("i=%d, e=%d", i, e)                                                 
  stdnse.debug1("Matching on >%s<", string.sub(fp, e, e+10))                        
  return unescape:match(getquote:match(fp, e+1))                                    
end