/* $NetBSD: midictl.h,v 1.3 2008/04/28 20:23:47 martin Exp $ */ /*- * Copyright (c) 2006 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Chapman Flack. * * 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. * * 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_MIDICTL_H_ #define _SYS_DEV_MIDICTL_H_ /* * General support for MIDI controllers, registered parameters, and * nonregistered parameters. It interprets MIDI messages that update * these values, maintains the associated state, and provides an API * for obtaining the current value of any controller or parameter and * tracking changes to it. * * One function provides the interface for message parsing. When a message * is received, once it has been determined to be a MIDI_CTL_CHANGE message, * simply call midictl_change(&mc, chan, ctlval) where chan is the channel * extracted from the first byte, and ctlval points to the remaining two * bytes of the message received. * * The API for reading the state is equally simple. Use * midictl_read(&mc, chan, ctlr, dflt) * midictl_rpn_read(&mc, chan, rpn, dflt) * midictl_nrpn_read(&mc, chan, nrpn, dflt) * to read the current value of controller #ctlr, RP #rpn, or NRP #nrpn, * respectively. (For 14-bit controllers, use the MSB number as ctlr, not * the LSB number.) You get the complete current value; for 14-bit controllers * and parameters you get a single 14-bit integer without fussing about the * multiple MIDI messages needed to set it. If you read a controller or * parameter that no MIDI message has yet written, you get back the value dflt. * If you read one whose MSB or LSB only has been written, you get what you * would get if the value had been dflt before the write. * * The functions may be called from any context but reentrant calls operating * on the same midictl are unsupported, with one exception: calls back into * midictl from a notify handler it has called are permitted. If you are * calling midictl_change in a driver function called by midi(4), you are ok * as midi(4) itself serializes its calls into the driver. For other uses, * avoiding reentrant calls is up to you. * * A strict division of labor limits complexity. This module knows as little * about the meanings of different MIDI parameters and controllers as possible * to do its job: it knows which controllers are overloaded to serve as * channel mode messages, and which are overloaded to provide access to the * RPN and NRPN space. It knows which controllers are 14-bit, 7-bit, or 1-bit * according to the table online at midi.org. (All parameters are treated as * 14-bit.) It does not know or care about the specified default values; * client code is expected to know those defaults for whatever controls it * actually implements, and supply them when calling midictl_*read(). That * avoids the need for a large table of specified values for things most * clients will never read. A header file defining the official defaults could * be useful for clients to include for use when calling midictl_*read, but * is not part of this module. Reset All Controllers is simply handled by * forgetting controllers have been written at all, so the next read by * the client will return the client's supplied default. * * An incoming MIDI stream may refer to many controllers and parameters the * client does not implement. To limit memory use, messages are ignored by * default if they target a controller or parameter the client has never * read. To indicate which controllers/parameters it supports, the client * should simply read them when starting. * * Where the task is to generically process some MIDI stream without losing * data, accept_any_ctl_rpn can be set to 1 in the midictl structure, and * state will be kept for any incoming controller or RPN update. The separate * flag accept_any_nrpn enables the same behavior for nonregistered parameters. * * Whenever a change is made to any value for which state is being kept, the * notify function will be called with MIDICTL_CTLR, MIDICTL_RPN, or * MIDICTL_NRPN, the channel, and the controller, rp, or nrp number, * respectively. The controller number will never refer to the LSB of a 14-bit * controller. The new /value/ is not included; if the change is of interest, * the client reads the value and thereby supplies the default (which can still * be needed if the update is to half of a 14-bit value). The notify function * is also called, with appropriate evt codes, on receipt of channel mode * messages. * * Reset All Controllers: * * The Reset All Controllers message will cause this module to forget settings * for all controllers on the affected channel other than those specifically * excepted by MIDI RP-015. Registered and nonregistered parameters are not * affected. The notify function is then called with evt = MIDICTL_RESET. * * The client's response to MIDICTL_RESET should include reading all * controllers it cares about, to ensure (if the accept_any_ctl_rpn flag is not * set) that they will continue to be tracked. The client must also reset to * defaults the following pieces of channel state that are not managed by this * module, but required by RP-015 to be reset: * Pitch Bend * Channel Pressure * Key Pressure (for all keys on channel) * The client does NOT reset the current Program. */ #include #include /* * Events that may be reported via a midictl_notify function. * Enum starts at 1<<16 so that enum|key can be used as a switch expression. * Key is 0 except where shown below. */ typedef enum { MIDICTL_CTLR = 1<<16, /* key=ctlr */ MIDICTL_RPN = 2<<16, /* key=rpn */ MIDICTL_NRPN = 3<<16, /* key=nrpn */ MIDICTL_RESET = 4<<16, /* Reset All Controllers received */ MIDICTL_NOTES_OFF = 5<<16, /* All Notes Off received */ MIDICTL_SOUND_OFF = 6<<16, /* All Sound Off received */ MIDICTL_LOCAL = 7<<16, /* if (key) localIsOn else localIsOff */ MIDICTL_MODE = 8<<16 /* key=mode(1-4)? TBD unimplemented */ } midictl_evt; /* * midictl_notify(void *cookie, midictl_evt evt, * uint_fast8_t chan, uint_fast16_t key) */ typedef void midictl_notify(void *, midictl_evt, uint_fast8_t, uint_fast16_t); typedef struct midictl_store midictl_store; typedef struct { uint_fast8_t accept_any_ctl_rpn:1; /* 0 ==> ignore chgs for unqueried */ uint_fast8_t accept_any_nrpn:1; /* likewise for NRPNs */ uint_fast8_t base_channel; /* set >= 16 to ignore any MODE messages */ void *cookie; /* this value will be passed to notify */ midictl_notify *notify; /* */ uint16_t rpn; uint16_t nrpn; midictl_store *store; } midictl; extern void midictl_open(midictl *); extern void midictl_close(midictl *); /* * Called on receipt of a Control Change message. Updates the controller, * RPN, or NRPN value as appropriate. When updating a controller or RPN that * is defined in the spec as boolean, all values that by definition represent * false are coerced to zero. Fires the callback if a value of interest has * been changed. * ctlval: points to the second byte of the message (therefore, to a two- * byte array: controller number and value). * midictl_change(midictl *mc, uint_fast8_t chan, uint8_t *ctlval); */ extern void midictl_change(midictl *, uint_fast8_t, uint8_t *); /* * Read the current value of controller ctlr for channel chan. * If this is the first time querying this controller on this channel, * and accept_any_ctl_rpn is false, any earlier change message for it * will have been ignored, so it will be given the value dflt, which is * also returned, and future change messages for it will take effect. * If the controller has a two-byte value and only one has been explicitly set * at the time of the first query, the effect is as if the value had been * first set to dflt, then the explicitly-set byte updated. * midictl_read(midictl *mc, uint_fast8_t chan, * uint_fast8_t ctlr, uint_fast16_t dflt); */ extern uint_fast16_t midictl_read(midictl *, uint_fast8_t, uint_fast8_t, uint_fast16_t); /* * As for midictl_read, but for registered parameters or nonregistered * parameters, respectively. */ extern uint_fast16_t midictl_rpn_read(midictl *mc, uint_fast8_t, uint_fast16_t, uint_fast16_t); extern uint_fast16_t midictl_nrpn_read(midictl *mc, uint_fast8_t, uint_fast16_t, uint_fast16_t); #endif /* _SYS_DEV_MIDICTL_H_ */