FreeBSD/Linux Kernel Cross Reference
sys/dev/midisynvar.h

     /*      $NetBSD: midisynvar.h,v 1.10 2006/06/30 13:56:25 chap Exp $     */
     
     /*
      * Copyright (c) 1998 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * This code is derived from software contributed to The NetBSD Foundation
      * by Lennart Augustsson (augustss@NetBSD.org).
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *        This product includes software developed by the NetBSD
     *        Foundation, Inc. and its contributors.
     * 4. Neither the name of The NetBSD Foundation nor the names of its
     *    contributors may be used to endorse or promote products derived
     *    from this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     * POSSIBILITY OF SUCH DAMAGE.
     */
    
    #ifndef _SYS_DEV_MIDISYNVAR_H_
    #define _SYS_DEV_MIDISYNVAR_H_
    
    #include "midictl.h"
    
    typedef struct midisyn midisyn;
    
    /*
     * Important: any synth driver that uses midisyn must set up its methods
     * structure in a way that refers to members /by name/ and zeroes the rest
     * (as is the effect of C99 initializers with designators). This discipline
     * will allow the structure to evolve methods for newly implemented
     * functionality or to exploit capabilities of new drivers with a minimal
     * versioning burden.  Because midisyn is at present a very rudimentary and
     * partial implementation, change should be expected in this set of methods.
     * Do not hesitate to add one in the course of implementing new stuff, as
     * long as it will be generally useful and there is some reasonable fallback
     * for drivers without it.
     */
    struct midisyn_methods {
            int  (*open)    (midisyn *, int /* flags */);
            void (*close)   (midisyn *);
            int  (*ioctl)   (midisyn *, u_long, caddr_t, int, struct lwp *);
            /*
             * allocv(midisyn *ms, uint_fast8_t chan, uint_fast8_t key);
             * Allocate one of the devices actual voices (stealing one if
             * necessary) to play note number 'key' (the MIDI note number, not
             * a frequency) associated with MIDI channel chan. An implementation
             * might want to choose a voice already last used on chan, to save
             * shuffling of patches.
             * One day a variant of this method will probably be needed, with an
             * extra argument indicating whether a melodic or percussive voice is
             * wanted.
             */
            uint_fast16_t  (*allocv)  (midisyn *, uint_fast8_t, uint_fast8_t);
            /*
             * attackv(midisyn *ms,
             *         uint_fast16_t voice, midipitch_t mp, int16_t level_cB);
             * Attack the voice 'voice' at pitch 'midipitch' with level 'level_cB'.
             * The pitch is in MIDI Tuning units and accounts for all of the pitch
             * adjustment controls that midisyn supports and that the driver has
             * not reported handling internally. The level is in centibels of
             * attenuation (0 == no attenuation, full output; reduced levels are
             * negative) and again accounts for all level adjustments midisyn
             * supports, except any the driver reports handling itself.
             * The program used for the voice should be the current program of the
             * voice's associated MIDI channel, and can be queried with MS_GETPGM.
             */
            void (*attackv)  (midisyn *, uint_fast16_t, midipitch_t, int16_t);
            /*
             * attackv_vel(midisyn *ms, uint_fast16_t voice,
             *             midipitch_t mp, int16_t level_cB, uint_fast8_t vel);
             * If the driver can do something useful with the voice's attack
             * velocity, such as vary the attack envelope or timbre, it should
             * provide this method. Velocity 64 represents the normal attack for
             * the patch, lower values are softer, higher harder. IF the driver
             * does not supply this method, midisyn will call the attackv method
             * instead, and include the velocity in the calculation of level_cB.
             */
            void (*attackv_vel) (midisyn *,
                                 uint_fast16_t, midipitch_t, int16_t, uint_fast8_t);
           /*
            * releasev(midisyn *ms, uint_fast16_t voice, uint_fast8_t vel);
            * Release the voice 'voice' with release velocity 'vel' where lower
            * values mean slower decay, 64 refers to the normal decay envelope
            * for the patch, and higher values mean decay faster.
            */
           void (*releasev) (midisyn *, uint_fast16_t, uint_fast8_t);
           /*
            * repitchv(midisyn *ms, uint_fast16_t voice, midipitch_t mp);
            * A driver should provide this method if it is able to change the
            * pitch of a sounding voice without rearticulating or glitching it.
            * [not yet implemented in midisyn]
            */
           void (*repitchv) (midisyn *, uint_fast16_t, midipitch_t);
           /*
            * relevelv(midisyn *ms, uint_fast16_t voice, int16_t level_cB);
            * A driver should provide this method if it is able to change the
            * level of a sounding voice without rearticulating or glitching it.
            * How the driver should adjust 'level_cB' to account for envelope
            * decay since the initial level is not (quite, yet) specified; the
            * driver may save the last level it got from midisyn, subtract from
            * this one, and use the difference to adjust the current level out of
            * the envelope generator. Or not.... [not yet implemented in midisyn]
            */
           void (*relevelv) (midisyn *, uint_fast16_t, int16_t);
           /*
            * pgmchg(midisyn *ms, uint_fast8_t chan, uint_fast8_t pgm);
            * If the driver supports changing programs, it should do whatever it
            * does AND be sure to store pgm in ms->pgms[chan].  (XXX?)
            */
           void (*pgmchg)  (midisyn *, uint_fast8_t, uint_fast8_t);
           /*
            * ctlnotice(midisyn *ms,
            *           midictl_evt evt, uint_fast8_t chan, uint_fast16_t key);
            * Reports any of the events on channel 'chan' that midictl (which see)
            * manages. Return 0 for a particular event if it is not handled by the
            * driver, nonzero if the driver handles it. Many events can be handled
            * by midisyn if the driver ignores them, but will be left to the driver
            * if it returns non-zero. For example, midisyn will usually combine
            * the volume and expression controllers, plus a note's attack velocity,
            * into a single 'level' parameter to attackv, but if the driver is
            * responding to the volume controller on its own, midisyn will leave
            * that controller out of the combined level computation.
            *   The driver should respond to MIDICTL_RESET events specially. There
            * are some items of state other than controllers that are specified to
            * be reset; if the driver keeps such state, it should be reset. The
            * driver should also midictl_read() all controllers it can respond to,
            * which will ensure that midictl tracks them.
            *   There are also things that RP-015 specifies do NOT get reset by
            * the MIDICTL_RESET event. Don't reset those. :)
            */
           int (*ctlnotice) (midisyn *, midictl_evt, uint_fast8_t, uint_fast16_t);
   };
   
   struct voice {
           u_int chan_note;        /* channel and note */
   #define MS_CHANNOTE(chan, note) ((chan) * 256 + (note))
   #define MS_GETCHAN(v) ((v)->chan_note >> 8)
           u_int seqno;            /* allocation index (increases with time) */
           int16_t velcB;          /* cB based on attack vel (relevel may need) */
           u_char inuse;
   };
   
   #define MIDI_MAX_CHANS 16
   
   struct channelstate;
   
   struct midisyn {
           /* Filled by synth driver */
           struct midisyn_methods *mets;
           char name[32];
           int nvoice;
           int flags;
           void *data;
   
           /* Set up by midisyn but available to synth driver for reading ctls */
           /*
            * Note - there is currently no locking on this structure; if the synth
            * driver interacts with midictl it should do so synchronously, when
            * processing a call from midisyn, and not at other times such as upon
            * an interrupt. (may revisit locking if problems crop up.)
            */
           midictl ctl;
           
           /* Used by midisyn driver */
           struct voice *voices;
           u_int seqno;
           u_int16_t pgms[MIDI_MAX_CHANS]; /* ref'd if driver uses MS_GETPGM */
           struct channelstate *chnstate;
   };
   
   #define MS_GETPGM(ms, vno) ((ms)->pgms[MS_GETCHAN(&(ms)->voices[vno])])
   
   struct midi_softc;
   
   extern const struct midi_hw_if midisyn_hw_if;
   
   void    midisyn_attach (struct midi_softc *, midisyn *);
   
   /*
    * Convert a 14-bit volume or expression controller value to centibels using
    * the General MIDI formula. The maximum controller value translates to 0 cB
    * (no attenuation), a half-range controller to -119 cB (level cut by 11.9 dB)
    * and a zero controller to INT16_MIN. If you are converting a 7-bit value
    * just shift it 7 bits left first.
    */
   extern int16_t midisyn_vol2cB(uint_fast16_t);
   
   #endif /* _SYS_DEV_MIDISYNVAR_H_ */

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