[PATCH 1/1] winecoreaudio: Avoid duplicate Program Change or Channel Aftertouch MIDI messages.

[Brendan Shanks]

From: Brendan Shanks

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=57805
---
 dlls/winecoreaudio.drv/coremidi.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/dlls/winecoreaudio.drv/coremidi.c b/dlls/winecoreaudio.drv/coremidi.c
index 9b1fbd28f6a..113d5d267b4 100644
--- a/dlls/winecoreaudio.drv/coremidi.c
+++ b/dlls/winecoreaudio.drv/coremidi.c
@@ -648,6 +648,7 @@ static UINT midi_out_data(WORD dev_id, UINT data)
 {
     struct midi_dest *dest;
     UInt8 bytes[3];
+    size_t count = sizeof(bytes);
     OSStatus sc;

TRACE("dev_id = %d data = %08x\n", dev_id, data);
@@ -692,7 +693,23 @@ static UINT midi_out_data(WORD dev_id, UINT data)
     }
     else
     {
-        midi_send(midi_out_port, dest->dest, bytes, sizeof(bytes));
+        /* MODM_DATA always includes 3 bytes, but some message types are only
+         * 1 or 2 bytes long. The docs say that "The driver must parse the event
+         * to determine how many bytes to transfer"
+         *
+         * Sending 3 bytes seems to work for most 1/2 byte messages
+         * (Core MIDI must be doing some parsing), but some 2 byte messages
+         * result in duplicates if all 3 bytes are sent.
+         */
+        switch (bytes[0] & 0xF0)
+        {
+            case 0xC0:  /* Program Change */
+            case 0xD0:  /* Channel Pressure (After-touch) */
+                count = 2;
+                break;
+        }
+
+        midi_send(midi_out_port, dest->dest, bytes, count);
     }

return MMSYSERR_NOERROR;