//
// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
// Creation Date: Thu Dec 24 15:38:37 PST 1998
// Last Modified: Thu Dec 24 15:45:15 PST 1998
// Filename:      ...linuxmidi/output/midipc.c
// Syntax:        C
// $Smake:        gcc -O3 -Wall -o %b %f && strip %b
//
// Description:  This program send a patch change command to an
//               External MIDI synthesizer.  Usage:
//               midipc instrument-number [midi-device-number]
//

#include <linux/soundcard.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>


// global variables:
int         seqfd = -1;               // sequencer file descriptor
const char* dev = "/dev/sequencer";   // name of sequencer device
int         status;                   // for error checking


// function declarations:
void sendPatchChange(int device, int patchnum);


int main(int argc, char** argv) {
   int numMidi = 0;                   // number of available MIDI outputs
   int instrument = 0;                // instrument to play (default = piano)
   int device = 0;                    // for selecting which MIDI output to use

   seqfd = open(dev, O_WRONLY, 0);
   if (seqfd < 0) {
      printf("Error: cannot open %s\n", dev);
      exit(1);
   }

   if (argc >= 2) {
      instrument = atoi(argv[1]);
   }
   if (argc >= 3) {
      device = argv[2][0] - '0';
   }

   status = ioctl(seqfd, SNDCTL_SEQ_NRMIDIS, &numMidi);
   if (status != 0) {
      printf("Error: cannot access MIDI devices on soundcard\n");
      exit(1);
   }
   printf("\nThere are: %d MIDI output devices available\n", numMidi);
   if (device >= numMidi) {
      printf("You specified an invalid MIDI device\n");
      exit(1);
   }
   printf("Device set to: %d\n", device);

   sendPatchChange(device, instrument);

   close(seqfd);
   return 0;
}


void sendPatchChange(int device, int patchnum) {
   unsigned char outpacket[8];

   outpacket[0] = SEQ_MIDIPUTC;
   outpacket[1] = 0xc0;              // patch change command (Channel 0)
   outpacket[2] = device;
   outpacket[3] = 0;

   outpacket[4] = SEQ_MIDIPUTC;
   // outpacket[5] will be the instrument number
   outpacket[6] = device;
   outpacket[7] = 0;

   outpacket[5] = patchnum & 0xff;
   write(seqfd, outpacket, 8);
}