1 /* $NetBSD: midictl.h,v 1.3 2008/04/28 20:23:47 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 2006 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Chapman Flack. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #ifndef _SYS_DEV_MIDICTL_H_ 33 #define _SYS_DEV_MIDICTL_H_ 34 35 /* 36 * General support for MIDI controllers, registered parameters, and 37 * nonregistered parameters. It interprets MIDI messages that update 38 * these values, maintains the associated state, and provides an API 39 * for obtaining the current value of any controller or parameter and 40 * tracking changes to it. 41 * 42 * One function provides the interface for message parsing. When a message 43 * is received, once it has been determined to be a MIDI_CTL_CHANGE message, 44 * simply call midictl_change(&mc, chan, ctlval) where chan is the channel 45 * extracted from the first byte, and ctlval points to the remaining two 46 * bytes of the message received. 47 * 48 * The API for reading the state is equally simple. Use 49 * midictl_read(&mc, chan, ctlr, dflt) 50 * midictl_rpn_read(&mc, chan, rpn, dflt) 51 * midictl_nrpn_read(&mc, chan, nrpn, dflt) 52 * to read the current value of controller #ctlr, RP #rpn, or NRP #nrpn, 53 * respectively. (For 14-bit controllers, use the MSB number as ctlr, not 54 * the LSB number.) You get the complete current value; for 14-bit controllers 55 * and parameters you get a single 14-bit integer without fussing about the 56 * multiple MIDI messages needed to set it. If you read a controller or 57 * parameter that no MIDI message has yet written, you get back the value dflt. 58 * If you read one whose MSB or LSB only has been written, you get what you 59 * would get if the value had been dflt before the write. 60 * 61 * The functions may be called from any context but reentrant calls operating 62 * on the same midictl are unsupported, with one exception: calls back into 63 * midictl from a notify handler it has called are permitted. If you are 64 * calling midictl_change in a driver function called by midi(4), you are ok 65 * as midi(4) itself serializes its calls into the driver. For other uses, 66 * avoiding reentrant calls is up to you. 67 * 68 * A strict division of labor limits complexity. This module knows as little 69 * about the meanings of different MIDI parameters and controllers as possible 70 * to do its job: it knows which controllers are overloaded to serve as 71 * channel mode messages, and which are overloaded to provide access to the 72 * RPN and NRPN space. It knows which controllers are 14-bit, 7-bit, or 1-bit 73 * according to the table online at midi.org. (All parameters are treated as 74 * 14-bit.) It does not know or care about the specified default values; 75 * client code is expected to know those defaults for whatever controls it 76 * actually implements, and supply them when calling midictl_*read(). That 77 * avoids the need for a large table of specified values for things most 78 * clients will never read. A header file defining the official defaults could 79 * be useful for clients to include for use when calling midictl_*read, but 80 * is not part of this module. Reset All Controllers is simply handled by 81 * forgetting controllers have been written at all, so the next read by 82 * the client will return the client's supplied default. 83 * 84 * An incoming MIDI stream may refer to many controllers and parameters the 85 * client does not implement. To limit memory use, messages are ignored by 86 * default if they target a controller or parameter the client has never 87 * read. To indicate which controllers/parameters it supports, the client 88 * should simply read them when starting. 89 * 90 * Where the task is to generically process some MIDI stream without losing 91 * data, accept_any_ctl_rpn can be set to 1 in the midictl structure, and 92 * state will be kept for any incoming controller or RPN update. The separate 93 * flag accept_any_nrpn enables the same behavior for nonregistered parameters. 94 * 95 * Whenever a change is made to any value for which state is being kept, the 96 * notify function will be called with MIDICTL_CTLR, MIDICTL_RPN, or 97 * MIDICTL_NRPN, the channel, and the controller, rp, or nrp number, 98 * respectively. The controller number will never refer to the LSB of a 14-bit 99 * controller. The new /value/ is not included; if the change is of interest, 100 * the client reads the value and thereby supplies the default (which can still 101 * be needed if the update is to half of a 14-bit value). The notify function 102 * is also called, with appropriate evt codes, on receipt of channel mode 103 * messages. 104 * 105 * Reset All Controllers: 106 * 107 * The Reset All Controllers message will cause this module to forget settings 108 * for all controllers on the affected channel other than those specifically 109 * excepted by MIDI RP-015. Registered and nonregistered parameters are not 110 * affected. The notify function is then called with evt = MIDICTL_RESET. 111 * 112 * The client's response to MIDICTL_RESET should include reading all 113 * controllers it cares about, to ensure (if the accept_any_ctl_rpn flag is not 114 * set) that they will continue to be tracked. The client must also reset to 115 * defaults the following pieces of channel state that are not managed by this 116 * module, but required by RP-015 to be reset: 117 * Pitch Bend 118 * Channel Pressure 119 * Key Pressure (for all keys on channel) 120 * The client does NOT reset the current Program. 121 */ 122 #include <sys/midiio.h> 123 #include <sys/stdint.h> 124 125 /* 126 * Events that may be reported via a midictl_notify function. 127 * Enum starts at 1<<16 so that enum|key can be used as a switch expression. 128 * Key is 0 except where shown below. 129 */ 130 typedef enum { 131 MIDICTL_CTLR = 1<<16, /* key=ctlr */ 132 MIDICTL_RPN = 2<<16, /* key=rpn */ 133 MIDICTL_NRPN = 3<<16, /* key=nrpn */ 134 MIDICTL_RESET = 4<<16, /* Reset All Controllers received */ 135 MIDICTL_NOTES_OFF = 5<<16, /* All Notes Off received */ 136 MIDICTL_SOUND_OFF = 6<<16, /* All Sound Off received */ 137 MIDICTL_LOCAL = 7<<16, /* if (key) localIsOn else localIsOff */ 138 MIDICTL_MODE = 8<<16 /* key=mode(1-4)? TBD unimplemented */ 139 } midictl_evt; 140 141 /* 142 * midictl_notify(void *cookie, midictl_evt evt, 143 * uint_fast8_t chan, uint_fast16_t key) 144 */ 145 typedef void 146 midictl_notify(void *, midictl_evt, uint_fast8_t, uint_fast16_t); 147 148 typedef struct midictl_store midictl_store; 149 150 typedef struct { 151 uint_fast8_t accept_any_ctl_rpn:1; /* 0 ==> ignore chgs for unqueried */ 152 uint_fast8_t accept_any_nrpn:1; /* likewise for NRPNs */ 153 uint_fast8_t base_channel; /* set >= 16 to ignore any MODE messages */ 154 void *cookie; /* this value will be passed to notify */ 155 midictl_notify *notify; 156 /* */ 157 uint16_t rpn; 158 uint16_t nrpn; 159 midictl_store *store; 160 } midictl; 161 162 extern void 163 midictl_open(midictl *); 164 165 extern void 166 midictl_close(midictl *); 167 168 /* 169 * Called on receipt of a Control Change message. Updates the controller, 170 * RPN, or NRPN value as appropriate. When updating a controller or RPN that 171 * is defined in the spec as boolean, all values that by definition represent 172 * false are coerced to zero. Fires the callback if a value of interest has 173 * been changed. 174 * ctlval: points to the second byte of the message (therefore, to a two- 175 * byte array: controller number and value). 176 * midictl_change(midictl *mc, uint_fast8_t chan, uint8_t *ctlval); 177 */ 178 extern void 179 midictl_change(midictl *, uint_fast8_t, uint8_t *); 180 181 /* 182 * Read the current value of controller ctlr for channel chan. 183 * If this is the first time querying this controller on this channel, 184 * and accept_any_ctl_rpn is false, any earlier change message for it 185 * will have been ignored, so it will be given the value dflt, which is 186 * also returned, and future change messages for it will take effect. 187 * If the controller has a two-byte value and only one has been explicitly set 188 * at the time of the first query, the effect is as if the value had been 189 * first set to dflt, then the explicitly-set byte updated. 190 * midictl_read(midictl *mc, uint_fast8_t chan, 191 * uint_fast8_t ctlr, uint_fast16_t dflt); 192 */ 193 extern uint_fast16_t 194 midictl_read(midictl *, uint_fast8_t, uint_fast8_t, uint_fast16_t); 195 196 /* 197 * As for midictl_read, but for registered parameters or nonregistered 198 * parameters, respectively. 199 */ 200 extern uint_fast16_t 201 midictl_rpn_read(midictl *mc, uint_fast8_t, uint_fast16_t, uint_fast16_t); 202 extern uint_fast16_t 203 midictl_nrpn_read(midictl *mc, uint_fast8_t, uint_fast16_t, uint_fast16_t); 204 205 #endif /* _SYS_DEV_MIDICTL_H_ */ 206