From d4e81258e6dc380b7501bd968c084196b1487993 Mon Sep 17 00:00:00 2001
From: Albert Graef <aggraef@gmail.com>
Date: Mon, 13 Aug 2018 10:23:51 +0200
Subject: [PATCH] Add an option (-k) to explicitly enable tracking of the
 on/off status of notes etc. This makes it easier to work with some devices,
 and breaks others. So it is now disabled by default, but can still be enabled
 when needed.

---
 midizap.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/midizap.c b/midizap.c
index 9ca7b07..56fcae3 100644
--- a/midizap.c
+++ b/midizap.c
@@ -459,6 +459,13 @@ static int16_t inpbvalue[2][16] =
    {8192, 8192, 8192, 8192, 8192, 8192, 8192, 8192,
     8192, 8192, 8192, 8192, 8192, 8192, 8192, 8192}};
 
+// If this option is enabled (-k on the command line), we make sure that each
+// "key" (note, cc, pb) is "off" before we allow it to go "on" again. This is
+// useful to eliminate double note-ons and the like, but interferes with the
+// way some controllers work, so it is disabled by default.
+
+static int keydown_tracker = 0;
+
 static uint8_t notedown[2][16][128];
 static uint8_t inccdown[2][16][128];
 static uint8_t inpbdown[2][16];
@@ -554,12 +561,12 @@ handle_event(uint8_t *msg, uint8_t portno)
   case 0x90:
     start_debug();
     if (msg[2]) {
-      if (!notedown[portno][chan][msg[1]]) {
+      if (!keydown_tracker || !notedown[portno][chan][msg[1]]) {
 	send_strokes(tr, portno, status, chan, msg[1], 0, 0);
 	notedown[portno][chan][msg[1]] = 1;
       }
     } else {
-      if (notedown[portno][chan][msg[1]]) {
+      if (!keydown_tracker || notedown[portno][chan][msg[1]]) {
 	send_strokes(tr, portno, status, chan, msg[1], 1, 0);
 	notedown[portno][chan][msg[1]] = 0;
       }
@@ -569,12 +576,12 @@ handle_event(uint8_t *msg, uint8_t portno)
   case 0xb0:
     start_debug();
     if (msg[2]) {
-      if (!inccdown[portno][chan][msg[1]]) {
+      if (!keydown_tracker || !inccdown[portno][chan][msg[1]]) {
 	send_strokes(tr, portno, status, chan, msg[1], 0, 0);
 	inccdown[portno][chan][msg[1]] = 1;
       }
     } else {
-      if (inccdown[portno][chan][msg[1]]) {
+      if (!keydown_tracker || inccdown[portno][chan][msg[1]]) {
 	send_strokes(tr, portno, status, chan, msg[1], 1, 0);
 	inccdown[portno][chan][msg[1]] = 0;
       }
@@ -628,12 +635,12 @@ handle_event(uint8_t *msg, uint8_t portno)
     start_debug();
     //fprintf(stderr, "pb %d\n", bend);
     if (bend) {
-      if (!inpbdown[portno][chan]) {
+      if (!keydown_tracker || !inpbdown[portno][chan]) {
 	send_strokes(tr, portno, status, chan, 0, 0, 0);
 	inpbdown[portno][chan] = 1;
       }
     } else {
-      if (inpbdown[portno][chan]) {
+      if (!keydown_tracker || inpbdown[portno][chan]) {
 	send_strokes(tr, portno, status, chan, 0, 1, 0);
 	inpbdown[portno][chan] = 0;
       }
@@ -663,8 +670,9 @@ handle_event(uint8_t *msg, uint8_t portno)
 
 void help(char *progname)
 {
-  fprintf(stderr, "Usage: %s [-h] [-o[2]] [-j name] [-r rcfile] [-d[rskmj]]\n", progname);
+  fprintf(stderr, "Usage: %s [-h] [-k] [-o[2]] [-j name] [-r rcfile] [-d[rskmj]]\n", progname);
   fprintf(stderr, "-h print this message\n");
+  fprintf(stderr, "-k keep track of key status (ignore double notes)\n");
   fprintf(stderr, "-o enable MIDI output (add 2 for a second pair of ports)\n");
   fprintf(stderr, "-j jack client name (default: midizap)\n");
   fprintf(stderr, "-r config file name (default: MIDIZAP_CONFIG_FILE variable or ~/.midizaprc)\n");
@@ -690,11 +698,15 @@ main(int argc, char **argv)
   uint8_t msg[3];
   int opt, count = 0;
 
-  while ((opt = getopt(argc, argv, "ho::d::j:r:")) != -1) {
+  while ((opt = getopt(argc, argv, "hko::d::j:r:")) != -1) {
     switch (opt) {
     case 'h':
       help(argv[0]);
       exit(0);
+    case 'k':
+      // see comment on -k and keydown_tracker above
+      keydown_tracker = 1;
+      break;
     case 'o':
       jack_num_outputs = 1;
       if (optarg && *optarg) {