levels = {[[
..........................
.000000000000000000000000.
.0......................0.
.0......................0.
.0......................0.
.0......................0.
.0.........00...........0.
.0.........00...........0.
.0......................0.
.0...............0......0.
.0......................0.
.0.........00...........0.
.0.s.......00...........0.
.000000000000000000000000.
..........................
]]
}

to_write = ""

--remove all "\n" from level strings
for i, v in ipairs(levels) do
  v = string.gsub(v, "\n", "")
  to_write = to_write.."    case "..(i-1)..":\n      memcpy(level, \""..v.."\", "..#v..");\n    break;"
end

--finish and write
to_write = [[#include "levels.h"
#include <gint/std/string.h>
void set_level(unsigned char level_id, char *level) {
  switch (level_id)
  {
]]..to_write.."\n  }\n}\n"
io.write(to_write)