//
// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
// Creation Date: Tue Dec 22 20:12:18 PST 1998
// Last Modified: Tue Dec 22 20:12:23 PST 1998
// Filename:      insimple.c
// Syntax:        C; pthread
// $Smake:        gcc -O3 -Wall -o %b %f -lpthread && strip %b 
//

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

#include <pthread.h>         /* for MIDI input interpreter thread */

#define  MIDI_DEVICE  "/dev/sequencer"

// global variables:
int                         seqfd;          // sequencer file descriptor
pthread_t                   midiInThread;   // thread blocker for midi input


// function declarations
void* threadFunction(void*);    // thread function for MIDI input interpreter


///////////////////////////////////////////////////////////////////////////
   

int main(void) {
   int status;            // for error checking

   // (1) first open the sequencer device for reading.
   //     some examples also have a nonblocking options in 2nd param

   seqfd = open(MIDI_DEVICE, O_RDONLY);
   if (seqfd == -1) {
      printf("Error: cannot open %s\n", MIDI_DEVICE);
      exit(1);
   } 


   // (2) now start the thread that interpreting incoming MIDI bytes:

   status = pthread_create(&midiInThread, NULL, threadFunction, NULL);
   if (status == -1) {
      printf("Error: unable to create MIDI input thread.\n");
      exit(1);
   } 


   // (3) finally, just wait around for MIDI messages to appear in the
   // input buffer and print them to the screen.

   while (1) {
      // do nothing, just wait around for thread function.
   }

   return 0;
}


///////////////////////////////////////////////////////////////////////////


//////////////////////////////
//
// threadFunction -- this function is sent to the pthread library
//    functions for running as a separate thread.
//

void* threadFunction(void* x) {
   unsigned char inbytes[4];         // bytes from sequencer driver
   int status;               // for error checking

   while (1) {
      status = read(seqfd, &inbytes, sizeof(inbytes));
      if (status < 0) {
         printf("Error reading %s\n", MIDI_DEVICE);
         exit(1);
      }
 
      if (inbytes[0] == SEQ_MIDIPUTC) {
         printf("received MIDI byte: %d\n", inbytes[1]);
      }
   }
}