update-protocol-ids

#! /usr/bin/env lua
--
-- update-protocol-ids
-- Copyright (C) 2016-2017, 2020 Adrian Perez <aperez@igalia.com>
--
-- Distributed under terms of the Apache License 2.0.
--

local help_msg = [[
Usage: update-protocol-ids [--help | -h | (--enum|--defs)]

Parse the input of the "ndpi_protocol_ids.h" header included as part of
the nDPI distribution and generate Lua code that mimics the definitions
of protocol type constants found in the header.

Input is read from standard input and written to standard output.
]]

if #arg == 0 or arg[1] == "--help" or arg[1] == "-h" then
	io.stderr:write(help_msg)
	os.exit(0)
end

local PATTERNS = {
   ["--enum"] = "NDPI_([^%s]+)%s*=%s*([%d_]+)";
   ["--defs"] = "^%#define%s+NDPI_([^%s]+)%s+([%d_]+)";
}

local item_pattern = PATTERNS[arg[1]]
if not item_pattern then
   io.stderr:write(help_msg)
   os.exit(1)
end

--
-- Parse the input header
--
local ref_pattern = "^%#define%s+NDPI_([^%s]+)%s+NDPI_([%a%d_]+)$"

local items = {}
local references = {}

for line in io.lines() do
	local name, value = line:match(item_pattern)
	if name and value and name ~= "LAST_IMPLEMENTED_PROTOCOL" then
      table.insert(items, { name = name, value = tonumber(value) })
   else
      name, value = line:match(ref_pattern)
      if name and value and value ~= "LAST_IMPLEMENTED_PROTOCOL" then
			table.insert(references, { name = name, value = value })
		end
   end
end
table.sort(items, function (a, b) return a.value < b.value end)

--
-- Generate Lua module
--
print("-- Generated by ljdnpi's tools/update-protocol-ids script")
print("local T = {")
for _, item in ipairs(items) do
   print("  [" .. item.value .. "] = \"" .. item.name .. "\",")
end
for _, item in ipairs(items) do
   print("  " .. item.name .. " = " .. item.value .. ",")
end
print("}")

for _, item in ipairs(references) do
   print("T." .. item.name .. " = T." .. item.value)
end

print("return T")