class FFI::TypesGenerator

def self.generate(options = {})
  typedefs = nil
  Tempfile.open 'ffi_types_generator' do |io|
    io.puts <<-C
lude <sys/types.h>
!(defined(WIN32))
lude <sys/socket.h>
lude <netinet/in.h>
lude <sys/resource.h>
if
    C
    io.close
    cc = ENV['CC'] || 'gcc'
    cmd = "#{cc} -E -x c #{options[:cppflags]} -D_DARWIN_USE_64_BIT_INODE -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -c"
    if options[:input]
      typedefs = File.read(options[:input])
    elsif options[:remote]
      typedefs = `ssh #{options[:remote]} #{cmd} - < #{io.path}`
    else
      typedefs = `#{cmd} #{io.path}`
    end
  end
  code = []
  typedefs.each_line do |type|
    # We only care about single line typedef
    next unless type =~ /typedef/
    # Ignore unions or structs
    next if type =~ /union|struct/
    # strip off the starting typedef and ending ;
    type.gsub!(/^(.*typedef\s*)/, "")
    type.gsub!(/\s*;\s*$/, "")
    parts = type.split(/\s+/)
    def_type   = parts.join(" ")
    # GCC does mapping with __attribute__ stuf, also see
    # http://hal.cs.berkeley.edu/cil/cil016.html section 16.2.7.  Problem
    # with this is that the __attribute__ stuff can either occur before or
    # after the new type that is defined...
    if type =~ /__attribute__/
      if parts.last =~ /__QI__|__HI__|__SI__|__DI__|__word__/
        # In this case, the new type is BEFORE __attribute__ we need to
        # find the final_type as the type before the part that starts with
        # __attribute__
        final_type = ""
        parts.each do |p|
          break if p =~ /__attribute__/
          final_type = p
        end
      else
        final_type = parts.pop
      end
      def_type = case type
                 when /__QI__/   then "char"
                 when /__HI__/   then "short"
                 when /__SI__/   then "int"
                 when /__DI__/   then "long long"
                 when /__word__/ then "long"
                 else                 "int"
                 end
      def_type = "unsigned #{def_type}" if type =~ /unsigned/
    else
      final_type = parts.pop
      def_type   = parts.join(" ")
    end
    if type = TYPE_MAP[def_type]
      code << "rbx.platform.typedef.#{final_type} = #{type}"
      TYPE_MAP[final_type] = TYPE_MAP[def_type]
    else
      # Fallback to an ordinary pointer if we don't know the type
      if def_type =~ /\*/
        code << "rbx.platform.typedef.#{final_type} = pointer"
        TYPE_MAP[final_type] = :pointer
      end
    end
  end
  code.sort.join("\n")
end