libalsa-ocaml-dev 0.2.1-1build5 / usr / lib / ocaml / alsa / alsa.mli

(*
   Copyright 2005-2006 Savonet team

   This file is part of Ocaml-alsa.

   Ocaml-shout is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   Ocaml-shout 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 General Public License
   along with Ocaml-shout; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*)

(**
  * Interface with the alsa drivers.
  *
  * @author Samuel Mimram
  *)

(* $Id$ *)

(** Get the ALSA sound library version in ASCII format. *)
val get_version : unit -> string

(** A buffer underrun / overrun occured. *)
exception Buffer_xrun
(** PCM is not in the right state. *)
exception Bad_state
(** A suspend event occurred (stream is suspended and waiting for an application
  * recovery). *)
exception Suspended

(** Input/output error. *)
exception IO_error
(** Device or resource was busy. *)
exception Device_busy
(** Function was called with an invalid argument. *)
exception Invalid_argument

(** This error can happen when device is physically 
  * removed (for example some hotplug devices like USB 
  * or PCMCIA, CardBus or ExpressCard can be removed on the fly). *)
exception Device_removed

exception Interrupted

exception Unknown_error of int

type direction =
  | Dir_down
  | Dir_eq
  | Dir_up

(** Get an error message corresponding to an error. 
  * Raise the given exception if it is not known. *)
val string_of_error : exn -> string

(** Do not report errors on stderr. *)
val no_stderr_report : unit -> unit

module Pcm :
sig
  (** Handle to a device. *)
  type handle

  (** Parameters of a device. *)
  type params

  (** Wanted stream. *)
  type stream =
    | Playback (** Playback stream. *)
    | Capture (** Capture stream. *)

  (** Modes for opening a stream. *)
  type mode =
    | Async (** Asynchronous notification (not supported yet). *)
    | Non_blocking (** Non blocking I/O. *)

  val open_pcm : string -> stream list -> mode list -> handle

  val close : handle -> unit

  (** Prepare PCM for use. *)
  val prepare : handle -> unit

  (** Resume from suspend, no samples are lost. *)
  val resume : handle -> unit

  (** Recover the stream state from an error or suspend.
    * This a high-level helper function building on other functions.
    * This functions handles Interrupted, Buffer_xrun and Suspended 
    * exceptions trying to prepare given stream for next I/O. 
    * Raises the given exception when not recognized/used. *)
  val recover : ?verbose:bool -> handle -> exn -> unit

  val start : handle -> unit

  (** Stop a PCM preserving pending frames. *)
  val drain : handle -> unit

  (** Stop a PCM dropping pending frames. *)
  val drop : handle -> unit

  (** [pause hnd pause] pauses (when [pause] is [true]) or resume (when [pause]
    * is [false]) a PCM. *)
  val pause : handle -> bool -> unit

  val reset : handle -> unit

  (** Wait for a PCM to become ready. The second argument is the timeout in
    * milliseconds (negative for infinite). Returns [false] if a timeout
    * occured. *)
  val wait : handle -> int -> bool

  (** [readi handle buf ofs len] reads [len] interleaved {i frames} in [buf]
    * starting at offset [ofs] (in bytes). It returns the actual number of
    * frames read. *)
  val readi : handle -> string -> int -> int -> int

  (** [writei handle buf ofs len] writes [len] interleaved {i frames} of [buf]
    * starting at offset [ofs] (in bytes). *)
  val writei : handle -> string -> int -> int -> int

  val readn : handle -> string array -> int -> int -> int

  val writen : handle -> string array -> int -> int -> int

  val readn_float : handle -> float array array -> int -> int -> int

  val writen_float : handle -> float array array -> int -> int -> int

  val readn_float64 : handle -> float array array -> int -> int -> int

  val writen_float64 : handle -> float array array -> int -> int -> int

  (** Get the delay (in frames). *)
  val get_delay : handle -> int

  (** State. *)
  type state =
    | St_open (** open *)
    | St_setup (** setup installed *)
    | St_prepared (** ready to start *)
    | St_running (** running *)
    | St_xrun (** stopped: underrun (playback) or overrun (capture) detected *)
    | St_draining (** draining: running (playback) or stopped (capture) *)
    | St_paused (** paused *)
    | St_suspended (** hardware is suspended *)
    | St_disconnected (** hardward is disconnected *)

  (** Get the current state. *)
  val get_state : handle -> state

  val get_params : handle -> params

  val set_params : handle -> params -> unit

  (** Access mode. *)
  type access =
    | Access_rw_interleaved
    | Access_rw_noninterleaved

  (** Set the access mode. *)
  val set_access : handle -> params -> access -> unit

  (** Format of audio data. *)
  type fmt =
    | Format_s16_le (** 16 bits, little endian *)
    | Format_s24_3le
    | Format_float (** float 32 bit CPU endian *)
    | Format_float64 (** float 64 bit CPU endian *)

  (** Set the format of audio data. *)
  val set_format : handle -> params -> fmt -> unit

  (** [set_rate_near handle params rate dir] sets the sampling rate (in Hz).
    * If the rate is not avalaible, [dir] is used to determine the direction of
    * the nearest available sampling rate to use . The actual sampling rate used
    * is returned. *)
  val set_rate_near : handle -> params -> int -> direction -> int

  (** Set the number of channels. *)
  val set_channels : handle -> params -> int -> unit

  (** Set the number of periods. *)
  val set_periods : handle -> params -> int -> direction -> unit

  (** Get the number of periods. *)
  val get_periods_min : params -> int*direction
  val get_periods_max : params -> int*direction

  (** Set the buffer size in {i frames}. *)
  val set_buffer_size : handle -> params -> int -> unit

  (** Set the buffer size near a value in {i frames}. *)
  val set_buffer_size_near : handle -> params -> int -> int

  (* Get the buffer's size. *)
  val get_buffer_size_min : params -> int
  val get_buffer_size_max : params -> int

  (** Set blocking mode ([true] means non-blocking). *)
  val set_nonblock : handle -> bool -> unit

  (** Get the size of a frame in bytes. *)
  val get_frame_size : params -> int
end