(*
 * Copyright 2011 The Savonet Team
 *
 * This file is part of ocaml-mm.
 *
 * ocaml-mm is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * ocaml-mm is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with ocaml-mm; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * As a special exception to the GNU Library General Public License, you may
 * link, statically or dynamically, a "work that uses the Library" with a publicly
 * distributed version of the Library to produce an executable file containing
 * portions of the Library, and distribute that executable file under terms of
 * your choice, without any of the additional requirements listed in clause 6
 * of the GNU Library General Public License.
 * By "a publicly distributed version of the Library", we mean either the unmodified
 * Library as distributed by The Savonet Team, or a modified version of the Library that is
 * distributed under the conditions defined in clause 3 of the GNU Library General
 * Public License. This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU Library General Public License.
 *
 *)

module G = Image.Generic

module V4L1 = struct
  type device = Unix.file_descr

  external opendev : string -> int -> int -> int -> device = "caml_v4l1_open"
  external grab : device -> G.data -> unit = "caml_v4l1_grab"
  external close : device -> unit = "caml_v4l1_close"
end

module V4L2 = struct
  type device = Unix.file_descr

  external opendev : string -> int -> int -> int -> device = "caml_v4l2_open"
  external grab : device -> G.data -> unit = "caml_v4l2_grab"
  external close : device -> unit = "caml_v4l2_close"
end

module V4L = V4L2

class reader device width height =
  object (self)
    val dev = V4L.opendev device width height (3 * width)

    val img =
      let data =
        Bigarray.Array1.create Bigarray.int8_unsigned Bigarray.c_layout
          (width * height * 3)
      in
      G.make_rgb G.Pixel.RGB24 width height data

    method frame_rate = 12.
    method width = width
    method height = height

    method read buf ofs len =
      V4L.grab dev (fst (G.rgb_data img));
      for i = ofs to ofs + len - 1 do
        buf.(i) <- Image.RGBA32.create width height;
        G.convert ~copy:true ~proportional:true img (G.of_RGBA32 buf.(i))
      done;
      len

    method close = V4L.close dev
  end
