rtbuf/rtbuf

diff --git a/.gitignore b/.gitignore
index edfff0d..c5e35f7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,17 +1,17 @@
-.deps/
-.libs/
-config.mk
 /cli/rtbuf
+config.mk
 /doc/
+.gdb_history
+*.gcda
+*.gcno
 /gtk3/rtbuf-gtk3
 /gtk3/rtbuf_gtk3_resources.c
-/lib/*_type
-/lib/*_type.h
+*.la
 /lib/.*.log
 /lib/*/.*.log
-.gdb_history
-*.la
+/lib/*_type
+/lib/*_type.h
+.libs/
 *.lo
 *.o
-*.gcno
-*.gcda
\ No newline at end of file
+*.tmp
diff --git a/Makefile b/Makefile
index a5600a1..985391d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,16 @@
+## rtbuf
+## Copyright 2018-2022 kmx.io <contact@kmx.io>
+##
+## Permission is hereby granted to use this software granted
+## the above copyright notice and this permission paragraph
+## are included in all copies and substantial portions of this
+## software.
+##
+## THIS SOFTWARE IS PROVIDED "AS-IS" WITHOUT ANY GUARANTEE OF
+## PURPOSE AND PERFORMANCE. IN NO EVENT WHATSOEVER SHALL THE
+## AUTHOR BE CONSIDERED LIABLE FOR THE USE AND PERFORMANCE OF
+## THIS SOFTWARE.
+
 all: build
 
 build:
@@ -21,4 +34,11 @@ install:
 	${MAKE} -C ${PWD}/cli      install
 	${MAKE} -C ${PWD}/gtk3     install
 
+licence:
+	elixir bin/header.exs config.subr ${RTBUF_CONFIGURES}
+	elixir bin/header.exs Makefile ${RTBUF_MAKEFILES}
+	elixir bin/header.exs librtbuf/rtbuf.h ${RTBUF_C_SOURCES}
+
 .PHONY: all build clean doc install
+
+include config.mk
diff --git a/bin/header.exs b/bin/header.exs
new file mode 100644
index 0000000..3d35f64
--- /dev/null
+++ b/bin/header.exs
@@ -0,0 +1,89 @@
+## cl89
+## Copyright 2022 kmx.io <contact@kmx.io>
+##
+## Permission is hereby granted to use this software granted
+## the above copyright notice and this permission paragraph
+## are included in all copies and substantial portions of this
+## software.
+##
+## THIS SOFTWARE IS PROVIDED "AS-IS" WITHOUT ANY GUARANTEE OF
+## PURPOSE AND PERFORMANCE. IN NO EVENT WHATSOEVER SHALL THE
+## AUTHOR BE CONSIDERED LIABLE FOR THE USE AND PERFORMANCE OF
+## THIS SOFTWARE.
+
+defmodule Header.C do
+  def split(src) do
+    split(src, "")
+  end
+
+  def split("/*" <> rest, "") do
+    split(rest, "/*")
+  end
+  def split("/*" <> rest, acc) do
+    {"", acc <> "/*" <> rest}
+  end
+  def split("*/\n" <> rest, acc) do
+    header = acc <> "*/"
+    {header, rest}
+  end
+  def split(<<c, rest::binary>>, acc) when is_binary(acc) do
+    split(rest, acc <> <<c>>)
+  end
+  def split("", acc) do
+    {"", acc}
+  end
+
+  def main([src_path | dest_paths]) do
+    case File.read(src_path) do
+      {:ok, src} ->
+        {header, _} = split(src)
+        Enum.each dest_paths, fn dest_path ->
+          {:ok, dest} = File.read(dest_path)
+          {_, rest} = split(dest)
+          result = header <> "\n" <> rest
+          File.write(dest_path, result)
+        end
+      {:error, e} ->
+        IO.inspect "Error: #{src_path}: #{e}"
+    end
+  end
+end
+
+defmodule Header.Make do
+  def split(src) do
+    split(src, [])
+  end
+
+  def split([line = ("#" <> _) | rest], acc) do
+    split(rest, [line | acc])
+  end
+  def split(rest, acc) do
+    {Enum.reverse(acc) |> Enum.join("\n"), rest |> Enum.join("\n")}
+  end
+
+  def main([src_path | dest_paths]) do
+    {:ok, src} = File.read(src_path)
+    src_lines = String.split(src, "\n")
+    {header, _} = split(src_lines)
+    Enum.each dest_paths, fn dest_path ->
+      {:ok, dest} = File.read(dest_path)
+      dest_lines = String.split(dest, "\n")
+      {_, rest} = split(dest_lines)
+      result = header <> "\n" <> rest
+      File.write(dest_path, result)
+    end
+  end
+end
+
+src_path = hd(System.argv)
+module = case src_path do
+           "Makefile" -> Header.Make
+           "configure" -> Header.Make
+           "config.subr" -> Header.Make
+           _ ->
+             case Regex.run(~r/[.][ch]$/, src_path) do
+               [_] -> Header.C
+               _ -> raise "error"
+             end
+         end
+module.main(System.argv)
diff --git a/config.subr b/config.subr
index 1c0ccd7..ad2b9df 100644
--- a/config.subr
+++ b/config.subr
@@ -1,4 +1,17 @@
 #!/bin/sh
+## rtbuf
+## Copyright 2018-2022 kmx.io <contact@kmx.io>
+##
+## Permission is hereby granted to use this software granted
+## the above copyright notice and this permission paragraph
+## are included in all copies and substantial portions of this
+## software.
+##
+## THIS SOFTWARE IS PROVIDED "AS-IS" WITHOUT ANY GUARANTEE OF
+## PURPOSE AND PERFORMANCE. IN NO EVENT WHATSOEVER SHALL THE
+## AUTHOR BE CONSIDERED LIABLE FOR THE USE AND PERFORMANCE OF
+## THIS SOFTWARE.
+
 set -e
 
 o_rule() {
@@ -37,8 +50,17 @@ require_pkg_config() {
     fi
 }
 
+update_config_mk() {
+    if ! cmp "${CONFIG_MK}" config.mk >/dev/null 2>&1; then
+        mv "${CONFIG_MK}" config.mk
+        echo "$PWD/config.mk"
+    else
+        rm "${CONFIG_MK}"
+    fi
+}
+
 CONFIG_MK=config.mk
-echo "$PWD/${CONFIG_MK}"
+CONFIG_MK=".config.mk.tmp"
 echo "# config.mk generated by configure" > ${CONFIG_MK}
 
 VER=0.4
diff --git a/configure b/configure
index 26f96bb..41e4b09 100755
--- a/configure
+++ b/configure
@@ -5,6 +5,17 @@ export SRCDIR="$PWD"
 
 . ./config.subr
 
+RTBUF_DIRS="librtbuf lib cli gtk3"
+RTBUF_CONFIGURES="$(find . -name "configure" | tr '\n' ' ')"
+RTBUF_MAKEFILES="$(find . -name "Makefile" | tr '\n' ' ')"
+RTBUF_C_SOURCES="$(find $RTBUF_DIRS -name "[a-z]*.c" -or -name "[a-z]*.h" -or -name "[a-z]*.c.in" -or -name "[a-z]*.h.in" | tr '\n' ' ')"
+
+echo "RTBUF_CONFIGURES = $RTBUF_CONFIGURES" >> ${CONFIG_MK}
+echo "RTBUF_MAKEFILES = $RTBUF_MAKEFILES" >> ${CONFIG_MK}
+echo "RTBUF_C_SOURCES = $RTBUF_C_SOURCES" >> ${CONFIG_MK}
+
+update_config_mk
+
 (cd librtbuf && ./configure)
 (cd lib && ./configure)
 (cd cli && ./configure)