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diff --git a/nselib/tab.lua b/nselib/tab.lua
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+---
+-- Arrange output into tables.
+--
+-- This module provides NSE scripts with a way to output structured tables
+-- similar to what <code>NmapOutputTable.cc</code> provides.
+--
+-- Example usage:
+-- <code>
+-- local t = tab.new()
+-- tab.add(t, 1, 'A1')
+-- tab.add(t, 2, 'A2')
+-- tab.nextrow(t)
+-- tab.add(t, 1, 'BBBBBBBBB1')
+-- tab.add(t, 2, 'BBB2')
+-- tab.nextrow(t)
+-- tab.addrow(t, 'C1', 'C2')
+-- tab.dump(t)
+-- </code>
+--
+-- <code>tab.add</code> works on the bottom-most row until
+-- <code>tab.nextrow</code> is called. Think of <code>tab.nextrow</code> as
+-- typing Enter at the end of a line. <code>tab.addrow</code> adds a whole row
+-- at a time and calls <code>tab.nextrow</code> automatically.
+--
+-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
+
+local stdnse = require "stdnse"
+local strbuf = require "strbuf"
+local string = require "string"
+local table = require "table"
+_ENV = stdnse.module("tab", stdnse.seeall)
+
+--- Create and return a new table.
+-- @return A new table.
+function new()
+  local t = {}
+
+  t.current_row = 1
+  setmetatable(t, {__tostring=dump})
+  return t
+end
+
+--- Add a new string item to a table at a given column position.
+--
+-- The item will be added to the current row. If <code>nextrow</code> hasn't
+-- been called yet that will be row 1.
+-- @param t The table.
+-- @param v The string to add.
+-- @param c The column position at which to add the item.
+function add(t, c, v)
+  assert(t)
+  assert(type(v) == "string")
+
+  -- add a new row if one doesn't exist
+  t[t.current_row] = t[t.current_row] or {}
+
+  t[t.current_row][c] = v
+  return true
+end
+
+--- Add a complete row to the table and move on to the next row.
+--
+-- Calls <code>add</code> for each argument starting with the second argument
+-- and after that calls <code>nextrow</code>.
+-- @param t The table.
+-- @param ... The elements to add to the row.
+function addrow(t, ...)
+  for i = 1, select("#", ...) do
+    add(t, i, tostring((select(i, ...))))
+  end
+  nextrow(t)
+end
+
+--- Move on to the next row in the table.
+--
+-- If this is not called then previous column values will be over-written by
+-- subsequent values.
+-- @param t The table.
+function nextrow(t)
+  assert(t)
+  assert(t.current_row)
+  t[t.current_row] = t[t.current_row] or {}
+  t.current_row = t.current_row + 1
+end
+
+--- Return a formatted string representation of the table.
+--
+-- The number of spaces in a column is based on the largest element in the
+-- column with an additional two spaces for padding.
+-- @param t The table.
+function dump(t)
+  assert(t)
+
+  local column_width = {}
+  local num_columns = {}
+  local buf = strbuf.new()
+
+  -- find widest element in each column
+  for i, row in ipairs(t) do
+    num_columns[i] = 0
+    for x, elem in pairs(row) do
+      local elem_width = #elem
+      if not column_width[x] or elem_width > column_width[x] then
+        column_width[x] = elem_width
+      end
+      if x > num_columns[i] then
+        num_columns[i] = x
+      end
+    end
+  end
+
+  -- build buf with padding so all column elements line up
+  for i, row in ipairs(t) do
+    local text_row = {}
+    for x = 1, num_columns[i] do
+      local elem = row[x] or ""
+      if x < num_columns[i] then
+        text_row[#text_row + 1] = elem .. string.rep(" ", column_width[x] - #elem)
+      else
+        text_row[#text_row + 1] = elem
+      end
+    end
+    buf = buf .. table.concat(text_row, "  ") .. "\n"
+  end
+
+  return strbuf.dump(buf)
+end
+
+return _ENV;