Mbed OS Reference | MIDIMessage.h Source File

 /*
  * Copyright (c) 2018-2019, Arm Limited and affiliates.
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 #ifndef MIDIMESSAGE_H
 #define MIDIMESSAGE_H
 
 #include <stdint.h>
 
 #define MAX_MIDI_MESSAGE_SIZE 256 // Max message size. SysEx can be up to 65536 but 256 should be fine for most usage
 
 // MIDI Message Format
 //
 // [ msg(4) | channel(4) ] [ 0 | n(7) ] [ 0 | m(7) ]
 //
 // MIDI Data Messages (Channel Specific)
 //
 // Message               msg n          m
 // ---------------------------------------------
 // Note Off              0x8 Key        Velocity
 // Note On               0x9 Key        Velocity
 // Polyphonic Aftertouch 0xA Key        Pressure
 // Control Change        0xB Controller Value
 // Program Change        0xC Program    -
 // Channel Aftertouch    0xD Pressure   -
 // Pitch Wheel           0xE LSB        MSB
 
 #define CABLE_NUM (0<<4)
 
 
 /**
  * \defgroup drivers_MIDIMessage MIDIMessage class
  * \ingroup drivers-internal-api-usb
  * @{
  */
 
 /** A MIDI message container */
 class MIDIMessage {
 public:
 
     MIDIMessage() : data(new uint8_t[MAX_MIDI_MESSAGE_SIZE + 1]), length(0) {}
 
     MIDIMessage(uint8_t *buf) : data(new uint8_t[MAX_MIDI_MESSAGE_SIZE + 1]), length(0)
     {
         for (int i = 0; i < 4; i++) {
             data[i] = buf[i];
         }
     }
 
     /**
      * Copy constructor
      */
     MIDIMessage(const MIDIMessage &other)
     {
         *this = other;
     }
 
     /**
      * Assignment operator
      */
     MIDIMessage &operator=(const MIDIMessage &other)
     {
         length = other.length;
         for (int i = 0; i < length; i++) {
             data[i] = other.data[i];
         }
 
         return *this;
     }
 
     ~MIDIMessage()
     {
         delete[] data;
     }
 
     /**
      * Set this MIDIMessage to a raw MIDI message
      *
      * @param buf is a true MIDI message (not USBMidi message)
      * @param buf_len size of message
      */
     void from_raw(uint8_t *buf, int buf_len)
     {
         length = buf_len + 1;
         if (length > MAX_MIDI_MESSAGE_SIZE) {
             // Message is too big
             length = 0;
             return;
         }
 
         // first byte keeped for retro-compatibility
         data[0] = CABLE_NUM | 0x08;
 
         for (int i = 0; i < buf_len; i++) {
             data[i + 1] = buf[i];
         }
     }
 
     // create messages
 
     /** Create a NoteOff message
      * @param key Key ID
      * @param velocity Key velocity (0-127, default = 127)
      * @param channel Key channel (0-15, default 0)
      * @returns A MIDIMessage
      */
     static MIDIMessage NoteOff(int key, int velocity = 127, int channel = 0)
     {
         MIDIMessage msg;
         msg.data[0] = CABLE_NUM | 0x08;
         msg.data[1] = 0x80 | (channel & 0x0F);
         msg.data[2] = key & 0x7F;
         msg.data[3] = velocity & 0x7F;
         msg.length = 4;
         return msg;
     }
 
     /** Create a NoteOn message
      * @param key Key ID
      * @param velocity Key velocity (0-127, default = 127)
      * @param channel Key channel (0-15, default 0)
      * @returns A MIDIMessage
      */
     static MIDIMessage NoteOn(int key, int velocity = 127, int channel = 0)
     {
         MIDIMessage msg;
         msg.data[0] = CABLE_NUM | 0x09;
         msg.data[1] = 0x90 | (channel & 0x0F);
         msg.data[2] = key & 0x7F;
         msg.data[3] = velocity & 0x7F;
         msg.length = 4;
         return msg;
     }
 
     /** Create a PolyPhonic Aftertouch message
      * @param key Key ID
      * @param pressure Aftertouch pressure (0-127)
      * @param channel Key channel (0-15, default 0)
      * @returns A MIDIMessage
      */
     static MIDIMessage PolyphonicAftertouch(int key, int pressure, int channel = 0)
     {
         MIDIMessage msg;
         msg.data[0] = CABLE_NUM | 0x0A;
         msg.data[1] = 0xA0 | (channel & 0x0F);
         msg.data[2] = key & 0x7F;
         msg.data[3] = pressure & 0x7F;
         msg.length = 4;
         return msg;
     }
 
     /** Create a Control Change message
      * @param control Controller ID
      * @param value Controller value (0-127)
      * @param channel Controller channel (0-15, default 0)
      * @returns A MIDIMessage
      */
     static MIDIMessage ControlChange(int control, int value, int channel = 0)
     {
         MIDIMessage msg;
         msg.data[0] = CABLE_NUM | 0x0B;
         msg.data[1] = 0xB0 | (channel & 0x0F);
         msg.data[2] = control & 0x7F;
         msg.data[3] = value & 0x7F;
         msg.length = 4;
         return msg;
     }
 
     /** Create a Program Change message
      * @param program Program ID
      * @param channel Channel (0-15, default 0)
      * @returns A MIDIMessage
      */
     static MIDIMessage ProgramChange(int program, int channel = 0)
     {
         MIDIMessage msg;
         msg.data[0] = CABLE_NUM | 0x0C;
         msg.data[1] = 0xC0 | (channel & 0x0F);
         msg.data[2] = program & 0x7F;
         msg.data[3] = 0x00;
         msg.length = 4;
         return msg;
     }
 
     /** Create a Channel Aftertouch message
      * @param pressure Pressure
      * @param channel Key channel (0-15, default 0)
      * @returns A MIDIMessage
      */
     static MIDIMessage ChannelAftertouch(int pressure, int channel = 0)
     {
         MIDIMessage msg;
         msg.data[0] = CABLE_NUM | 0x0D;
         msg.data[1] = 0xD0 | (channel & 0x0F);
         msg.data[2] = pressure & 0x7F;
         msg.data[3] = 0x00;
         msg.length = 4;
         return msg;
     }
 
     /** Create a Pitch Wheel message
      * @param pitch Pitch (-8192 - 8191, default = 0)
      * @param channel Channel (0-15, default 0)
      * @returns A MIDIMessage
      */
     static MIDIMessage PitchWheel(int pitch = 0, int channel = 0)
     {
         MIDIMessage msg;
         int p = pitch + 8192;    // 0 - 16383, 8192 is center
         msg.data[0] = CABLE_NUM | 0x0E;
         msg.data[1] = 0xE0 | (channel & 0x0F);
         msg.data[2] = p & 0x7F;
         msg.data[3] = (p >> 7) & 0x7F;
         msg.length = 4;
         return msg;
     }
 
     /** Create an All Notes Off message
      * @param channel Channel (0-15, default 0)
      * @returns A MIDIMessage
      */
     static MIDIMessage AllNotesOff(int channel = 0)
     {
         return ControlChange(123, 0, channel);
     }
 
     /** Create a SysEx message
     * @param data SysEx data (including 0xF0 .. 0xF7)
     * @param len SysEx data length
     * @returns A MIDIMessage
     */
     static MIDIMessage SysEx(uint8_t *data, int len)
     {
         MIDIMessage msg;
         msg.from_raw(data, len);
         return msg;
     }
 
     // decode messages
 
     /** MIDI Message Types */
     enum MIDIMessageType {
         ErrorType,
         NoteOffType,
         NoteOnType,
         PolyphonicAftertouchType,
         ControlChangeType,
         ProgramChangeType,
         ChannelAftertouchType,
         PitchWheelType,
         ResetAllControllersType,
         AllNotesOffType,
         SysExType
     };
 
     /** Read the message type
      *
      * @returns MIDIMessageType
      */
     MIDIMessageType type()
     {
         MIDIMessageType message_type;
         uint8_t min_size;
         switch ((data[1] >> 4) & 0xF) {
             case 0x8:
                 // message, channel
                 // key
                 // velocity
                 min_size = 3;
                 message_type = NoteOffType;
                 break;
             case 0x9:
                 // message, channel
                 // key
                 // velocity
                 min_size = 3;
                 message_type = NoteOnType;
                 break;
             case 0xA:
                 // message, channel
                 // key
                 // pressure
                 min_size = 3;
                 message_type = PolyphonicAftertouchType;
                 break;
             case 0xB:
                 // message, channel
                 // controller
                 min_size = 2;
                 if ((data[2] & 0x7F) < 120) { // standard controllers
                     message_type = ControlChangeType;
                 } else if ((data[2] & 0x7F) == 121) {
                     message_type = ResetAllControllersType;
                 } else if ((data[2] & 0x7F) == 123) {
                     message_type = AllNotesOffType;
                 } else {
                     message_type = ErrorType; // unsupported atm
                 }
                 break;
             case 0xC:
                 // message, channel
                 // program
                 min_size = 2;
                 message_type = ProgramChangeType;
                 break;
             case 0xD:
                 // message, channel
                 // pressure
                 min_size = 2;
                 message_type = ChannelAftertouchType;
                 break;
             case 0xE:
                 // message, channel
                 // pitch lsb
                 // pitch msb
                 min_size = 3;
                 message_type = PitchWheelType;
                 break;
             case 0xF:
                 min_size = 2;
                 message_type = SysExType;
                 break;
             default:
                 message_type = ErrorType;
                 break;
         }
 
 
         if (length < min_size) {
             // too small to be a valid message
             message_type = ErrorType;
         }
         return message_type;
     }
 
     /**
      * Read the channel number
      *
      * @return channel number or -1 on error
      */
 
     int channel()
     {
         return (data[1] & 0x0F);
     }
 
     /**
      * Read the key ID
      *
      * @return key ID or -1 on error
      */
     int key()
     {
         MIDIMessageType msg_type = type();
         if ((msg_type != NoteOffType) &&
                 (msg_type != NoteOnType) &&
                 (msg_type != PolyphonicAftertouchType)) {
             return -1;
         }
 
         return data[2] & 0x7F;
     }
 
     /**
      * Read the velocity
      *
      * @return velocity or -1 on error
      */
     int velocity()
     {
         MIDIMessageType msg_type = type();
         if ((msg_type != NoteOffType) &&
                 (msg_type != NoteOnType)) {
             return -1;
         }
 
         return data[3] & 0x7F;
     }
 
     /**
      * Read the controller value
      *
      * @return controller value or -1 on error
      */
     int value()
     {
         MIDIMessageType msg_type = type();
         if ((msg_type != ControlChangeType) &&
                 (msg_type != ResetAllControllersType) &&
                 (msg_type != AllNotesOffType)) {
             return -1;
         }
 
         return data[3] & 0x7F;
     }
 
     /**
      * Read the aftertouch pressure
      *
      * @return aftertouch pressure or -1 on error
      */
     int pressure()
     {
         MIDIMessageType msg_type = type();
         if ((msg_type != PolyphonicAftertouchType) &&
                 (msg_type != ChannelAftertouchType)) {
             return -1;
         }
 
         if (type() == PolyphonicAftertouchType) {
             return data[3] & 0x7F;
         } else {
             return data[2] & 0x7F;
         }
     }
 
     /**
      * Read the controller number
      *
      * @return controller number or -1 on error
      */
     int controller()
     {
         MIDIMessageType msg_type = type();
         if ((msg_type != ControlChangeType) &&
                 (msg_type != ResetAllControllersType) &&
                 (msg_type != AllNotesOffType)) {
             return -1;
         }
 
         return data[2] & 0x7F;
     }
 
     /**
      * Read the program number
      *
      * @return program number or -1 on error
      */
     int program()
     {
         MIDIMessageType msg_type = type();
         if (msg_type != ProgramChangeType) {
             return -1;
         }
 
         return data[2] & 0x7F;
     }
 
     /**
      * Read the pitch value
      *
      * @return pitch value or -1 on error
      */
     int pitch()
     {
         MIDIMessageType msg_type = type();
         if (msg_type != PitchWheelType) {
             return -1;
         }
 
         int p = ((data[3] & 0x7F) << 7) | (data[2] & 0x7F);
         return p - 8192; // 0 - 16383, 8192 is center
     }
 
     uint8_t *data;
     uint16_t length;
 };
 
 /** @}*/
 
 #endif
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