MIDI input in LinuxStephen Travis Pope stp at create.ucsb.eduTue Mar 9 21:22:18 UTC 1999
Luciano Notarfrancesco wrote: > I want to use a MIDI keyboard with Squeak in Linux. Have anyone > implemented the MIDI input primitives for Linux? Not to my knowledge, but I know of some users who would *really* appreciate it! Here's the header file for the current Siren primitives (supported on Mac and Windows, port to SGI under way). The Mac implementation of this can be found at ftp://ftp.create.ucsb.edu/pub/Smalltalk/Music/Siren/2.0/VM%20Src/sqMacMIDI.OMS.c /*********************************************************************************** * * Header File for the Squeak Interface to MIDI * Stephen T. Pope -- stp at create.ucsb.edu -- 1998.05.05 * * Version 2.00B -- Squeak MIDI Primitive Interface * * This file should be platform- and driver-independent. * * Note: Most of the primitives fail only under extreme conditions, and return * negative results for "normal" failure. * A return value of 0 normally means "success" or "true." * * The Smalltalk primitive bindings are: * (610 primitiveOpenMIDI) * (611 primitiveCloseMIDI) * (612 primitiveGetMIDIDeviceName) * (613 primitivePutMIDIOn) * (614 primitiveReadMIDIPacket) * (615 primitiveReadMIDIControl) * (616 primitiveMIDIioctl) */ /*********************************************************************************** * External MIDI interface function prototypes (Smalltalk primitives) */ // Open/start the MIDI interface. (Prim. 610) // Answer the number of connected devices, or 0 if the driver's // already open. // 'readSemaphore' is the index of the semaphore to signal on MIDI // input if it's non-zero and input signalling is turned on (see the // ioctl commands below). // 'readSocket' is the socket to read from; writeSocket will be // readSocket + 1 (if readSocket's 0, don't use sockets at all). // (The socket is ignored in the default driver.) int sqOpenMIDI(int readSemaphore, int inputSocket); // Close the MIDI interface and disconnect from the driver (611) int sqCloseMIDI(void); // Get the name of a MIDI device. (612) // 'index' is a table index (up to the number of devices answered // by the sqOpenMIDI call). // 'name' is interpreted as (char *) and is written into--the Smalltalk // code must pre-allocate a ByteArray of size 64 or greater. // Answer the interface's direction (see sqMIDIioPort struct below). int sqGetMIDIDeviceName(int tableIndex, int deviceName); // Send data to the given device now. (613) // 'message' is interpreted as (unsigned char *); // 'length' is the number of bytes of data to send. // 'interface' is the number of a device. // Answer the number of bytes written. int sqMIDIPlaySizeOn(int MIDImessage, int length, int device); // Read input into a MIDI packet. (614) // 'MIDIpacket' is interpreted as (MIDIPacket *) and is written into // with the time-stamp, flags, and length. // 'dataBuffer' is interpreted as (unsigned char *) and gets the MIDI // message data. // Answer the number of data bytes in the packet. int sqReadMIDIPacket(int MIDIpacket, int maxSize, int dataBuffer); // Answer the last-read value of the selected MIDI controller(s) // (assuming controller value caching is turned on). (615) // Return 0 as a value for controllers for which no data has come // in (or should this be an error?). // The function stores results values into the array 'into', which // is interpreted as (int *). // Controller numbers of 0-127 are for the normal MIDI controllers, // 128-255 are for polyphonic key pressures; // 256-271 are for channel pressures; // 272-287 are used for pitchBend. // The return value the number of values actually read. int sqReadMIDIControl(int fromController, int toController, int into); // General-purpose MIDI driver feature query/set call (like UNIX // device driver ioctl() calls). (616) // 'which' selects the operation (see the flags defined below); // 'onOff' is a flag for choosing query/set/clear operations // Answer the result (true/false, or a number) int sqMIDIioctl(int whichIoctl, int onOff); /*********************************************************************************** * MIDI Driver ioctl flags */ ////////// ioctl selectors ////////// // Is a MIDI driver installed? True iff the VM includes the MIDI // prims and can successfully open the OS-level MIDI driver. #define sqMIDIInstalled 1 // What driver version is this? (May be platform-specific.) #define sqMIDIVersion 2 // Is there a time-stamped output buffer? If yes, you may use an // extended version of the sqMIDIPlaySizeOn primitive that includes // an offset time so you can schedule events in the future // (e.g., sqMIDIPlaySizeOnAt). #define sqMIDIHasBuffer 3 // Is there a 1-call note command? If yes, you may use an extended // version of the sqMIDIPlaySizeOn primitive that includes the note // duration and schedules note-off messages in the driver. // (e.g., sqMIDIPlaySizeOnAtDur). #define sqMIDIHasDurs 4 // Does the driver have its own clock? If yes, there may be special // primitives to get/set its value. #define sqMIDIHasClock 5 // Should the driver signal a semaphore in input? If yes, the semaphore // passed down in the sqOpenMIDI call will be signalled on all event // input, and also on controller input of controller caching is turned off. #define sqMIDIUseSemaphore 6 // Should we echo in-coming events from the driver? If yes, all incoming // packets are echo'ed immediately. #define sqMIDIEcho 7 // Should we cache controller values for polling? If yes, controller messages // do not trigger the read semaphore, but the controller values are stored in // tables in the driver. If on, it is assumed that applications will poll for // controller values using sqReadMIDIControl. #define sqMIDIControllerCache 8 // How many events are in the input Q? Answers the number of available packets. #define sqMIDIEventsAvailable 9 // Special flag to flush the driver's I/O buffers. #define sqMIDIFlushDriver 10 ////////// ioctl arguments ////////// #define sqMIDIQuery 0 // Query about the state of a feature or flag #define sqMIDITurnOn 1 // Turn it on #define sqMIDITurnOff 2 // Turn it off /*********************************************************************************** * MIDI Command Codes */ #define NoteOnCmd 0x90 #define NoteOffCmd 0x80 #define PgmChngCmd 0xC0 #define ControlCmd 0xB0 #define PolyPressCmd 0xA0 #define ChanPressCmd 0xD0 #define PchWheelCmd 0xE0 #define SysExCmd 0xF0 /*********************************************************************************** * Event queue entry struct */ #define PKT_LEN 255 typedef struct sqMIDIEvent { long startTime; // start time in clock ticks long timeStamp; // timestamp in arbitrary units unsigned char flags; // continutation, timestamped, etc. unsigned char len; // number of MIDI bytes unsigned char data[PKT_LEN]; // MIDI data buffer } sqMIDIEvent; /*********************************************************************************** * I/O Port struct */ typedef struct sqMIDIioPort { char name[64]; // port name int direction; // port direction 1=in, 2=out, 3=both } sqMIDIioPort; /*********************************************************************************** * E N D */ -- stp Stephen Travis Pope | stp at create.ucsb.edu | http://www.create.ucsb.edu/~stp
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