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move all device related stuff from aucat.c to a new dev.c file.
The new dev_xxx() routines expose a "high level" self-contained
interface to the device. At initialization, the device is opened
and two chains of aproc structures are created:

 * a playback chain that exposes a (initially) empty mix
   aproc to which the rest of the code can attach new
   streams to be played

 * record chain that exposes a (initially) empty sub aproc
   to which the rest of the code can attach new stream to
   to record

The rest of the code, has just to use dev_attach() routine to
attach streams. While we're at it, add a ``devops'' structure
containing pointers to the device-specific routines. This will
allow later to add support for other type of device than the
Sun API.

Also, write the .wav headers in file_del(), so put all header
related data in the file strucuture. This allows to close() the
file, as soon as wpipe_xxx() aproc terminates. This will be
useful for the server, because it will need to close() descripts
of closed connections immediately.

add mix_pushzero() routine to fill the mixer with silence. It
will be used to avoid the mixer to underrun when there are no
input streams. Since we always have at least one input stream
there's no behaviour change.

ok jakemsr

/*	$OpenBSD: aproc.h,v 1.5 2008/08/14 09:58:55 ratchov Exp $	*/
/*
 * Copyright (c) 2008 Alexandre Ratchov <alex@caoua.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#ifndef APROC_H
#define APROC_H

#include <sys/queue.h>

#include "aparams.h"

struct abuf;
struct aproc;
struct file;

struct aproc_ops {
	/*
	 * Name of the ops structure, ie type of the unit.
	 */
	char *name;

	/*
	 * The state of the given input abuf changed (eg. an input block
	 * is ready for processing). This function must get the block
	 * from the input, process it and remove it from the buffer.
	 *
	 * Processing the block will result in a change of the state of
	 * OTHER buffers that are attached to the aproc (eg. the output
	 * buffer was filled), thus this routine MUST notify ALL aproc
	 * structures that are waiting on it; most of the time this
	 * means just calling abuf_flush() on the output buffer.
	 */
	int (*in)(struct aproc *, struct abuf *);

	/*
	 * The state of the given output abuf changed (eg. space for a
	 * new output block was made available) so processing can
	 * continue.  This function must process more input in order to
	 * fill the output block.
	 *
	 * Producing a block will result in the change of the state of
	 * OTHER buffers that are attached to the aproc, thus this
	 * routine MUST notify ALL aproc structures that are waiting on
	 * it; most of the time this means calling abuf_fill() on the
	 * source buffers.
	 *
	 * Before filling input buffers (using abuf_fill()), this
	 * routine must ALWAYS check for eof condition, and if needed,
	 * handle it appropriately and call abuf_hup() to free the input
	 * buffer.
	 */
	int (*out)(struct aproc *, struct abuf *);

	/*
	 * The input buffer is empty and we can no more receive data
	 * from it. The buffer will be destroyed as soon as this call
	 * returns so the abuf pointer will stop being valid after this
	 * call returns. There's no need to drain the buffer because the
	 * in() call-back was just called before.
	 *
	 * If this call reads and/or writes data on other buffers,
	 * abuf_flush() and abuf_fill() must be called appropriately.
	 */
	void (*eof)(struct aproc *, struct abuf *);

	/*
	 * The output buffer can no more accept data (it should be
	 * considered as full). After this function returns, it will be
	 * destroyed and the "abuf" pointer will be no more valid.
	 */
	void (*hup)(struct aproc *, struct abuf *);

	/*
	 * A new input was connected.
	 */
	void (*newin)(struct aproc *, struct abuf *);

	/*
	 * A new output was connected
	 */
	void (*newout)(struct aproc *, struct abuf *);

	/*
	 * destroy the aproc, called just before to free the
	 * aproc structure
	 */
	void (*done)(struct aproc *);
};

struct aconv {
	/*
	 * Format of the buffer. This part is used by conversion code.
	 */

	int bfirst;		/* bytes to skip at startup */
	unsigned rate;		/* frames per second */
	unsigned pos;		/* current position in the stream */
	unsigned nch;		/* number of channels: nch = cmax - cmin + 1 */
	unsigned bps;		/* bytes per sample (padding included) */
	unsigned shift;		/* shift to get 32bit MSB-justified int */
	int sigbit;		/* sign bits to XOR to unsigned samples */
	int bnext;		/* bytes to skip to reach the next byte */
	int snext;		/* bytes to skip to reach the next sample */
	unsigned cmin;		/* provided/consumed channels */
	unsigned bpf;		/* bytes per frame: bpf = nch * bps */
	int ctx[CHAN_MAX];	/* current frame (for resampling) */
};

/*
 * The aproc structure represents a simple audio processing unit; they are
 * interconnected by abuf structures and form a kind of "circuit". The circuit
 * cannot have loops.
 */
struct aproc {
	char *name;				/* for debug purposes */
	struct aproc_ops *ops;			/* call-backs */
	LIST_HEAD(, abuf) ibuflist;		/* list of inputs */
	LIST_HEAD(, abuf) obuflist;		/* list of outputs */
	union {					/* follow type-specific data */
		struct {			/* file/device io */
			struct file *file;	/* file to read/write */
		} io;
		struct {
			struct aconv ist, ost;
		} conv;
		struct {
#define MIX_DROP	1
#define MIX_AUTOQUIT	2
			unsigned flags;
		} mix;
		struct {
#define SUB_DROP	1
#define SUB_AUTOQUIT	2
			unsigned flags;
		} sub;
	} u;
};

struct aproc *aproc_new(struct aproc_ops *, char *);
void aproc_del(struct aproc *);
void aproc_setin(struct aproc *, struct abuf *);
void aproc_setout(struct aproc *, struct abuf *);

struct aproc *rpipe_new(struct file *);
int rpipe_in(struct aproc *, struct abuf *);
int rpipe_out(struct aproc *, struct abuf *);
void rpipe_done(struct aproc *);
void rpipe_eof(struct aproc *, struct abuf *);
void rpipe_hup(struct aproc *, struct abuf *);

struct aproc *wpipe_new(struct file *);
void wpipe_done(struct aproc *);
int wpipe_in(struct aproc *, struct abuf *);
int wpipe_out(struct aproc *, struct abuf *);
void wpipe_eof(struct aproc *, struct abuf *);
void wpipe_hup(struct aproc *, struct abuf *);

struct aproc *mix_new(void);
struct aproc *sub_new(void);
struct aproc *conv_new(char *, struct aparams *, struct aparams *);

void mix_pushzero(struct aproc *);
void mix_setmaster(struct aproc *);

#endif /* !defined(FIFO_H) */