Update backend API: read-only MIDI input buffers

4 files changed, 22 insertions, 17 deletions

diff --git a/libs/ardour/ardour/mididm.h b/libs/ardour/ardour/mididm.h
index 65ed15ab72..5ee964c8e0 100644
--- a/libs/ardour/ardour/mididm.h
+++ b/libs/ardour/ardour/mididm.h
@@ -41,8 +41,8 @@ public:
 	bool       have_signal (void) { return (_monotonic_cnt - _last_signal_tme) < (uint64_t) _sample_rate ; }
 
 private:
-	int64_t parse_mclk (uint8_t* buf, pframes_t timestamp) const;
-	int64_t parse_mtc  (uint8_t* buf, pframes_t timestamp) const;
+	int64_t parse_mclk (uint8_t const * const buf, pframes_t timestamp) const;
+	int64_t parse_mtc  (uint8_t const * const buf, pframes_t timestamp) const;
 
 	framecnt_t _sample_rate;
 
diff --git a/libs/ardour/ardour/port_engine.h b/libs/ardour/ardour/port_engine.h
index a6fa2a5c84..647253baea 100644
--- a/libs/ardour/ardour/port_engine.h
+++ b/libs/ardour/ardour/port_engine.h
@@ -245,7 +245,7 @@ class LIBARDOUR_API PortEngine {
     * of the current process cycle, in samples) will be stored in @param
     * timestamp
     */
-    virtual int      midi_event_get (pframes_t& timestamp, size_t& size, uint8_t** buf, void* port_buffer, uint32_t event_index) = 0;
+    virtual int      midi_event_get (pframes_t& timestamp, size_t& size, uint8_t const** buf, void* port_buffer, uint32_t event_index) = 0;
 
     /** Place a MIDI event consisting of @param size bytes copied from the data
      * at @param buf into the port buffer referred to by @param
diff --git a/libs/ardour/midi_port.cc b/libs/ardour/midi_port.cc
index 9a52aef3c6..7a87c4c273 100644
--- a/libs/ardour/midi_port.cc
+++ b/libs/ardour/midi_port.cc
@@ -129,28 +129,33 @@ MidiPort::get_midi_buffer (pframes_t nframes)
 
 				pframes_t timestamp;
 				size_t size;
-				uint8_t* buf;
+				uint8_t const* buf;
 
 				port_engine.midi_event_get (timestamp, size, &buf, buffer, i);
 
 				if (buf[0] == 0xfe) {
 					/* throw away active sensing */
 					continue;
-				} else if ((buf[0] & 0xF0) == 0x90 && buf[2] == 0) {
-					/* normalize note on with velocity 0 to proper note off */
-					buf[0] = 0x80 | (buf[0] & 0x0F);  /* note off */
-					buf[2] = 0x40;  /* default velocity */
 				}
 
 				/* check that the event is in the acceptable time range */
+				if ((timestamp <  (_global_port_buffer_offset + _port_buffer_offset)) ||
+				    (timestamp >= (_global_port_buffer_offset + _port_buffer_offset + nframes))) {
+					cerr << "Dropping incoming MIDI at time " << timestamp << "; offset="
+						<< _global_port_buffer_offset << " limit="
+						<< (_global_port_buffer_offset + _port_buffer_offset + nframes) << "\n";
+					continue;
+				}
 
-				if ((timestamp >= (_global_port_buffer_offset + _port_buffer_offset)) &&
-				    (timestamp < (_global_port_buffer_offset + _port_buffer_offset + nframes))) {
-					_buffer->push_back (timestamp, size, buf);
+				if ((buf[0] & 0xF0) == 0x90 && buf[2] == 0) {
+					/* normalize note on with velocity 0 to proper note off */
+					uint8_t ev[3];
+					ev[0] = 0x80 | (buf[0] & 0x0F);  /* note off */
+					ev[1] = buf[1];
+					ev[2] = 0x40;  /* default velocity */
+					_buffer->push_back (timestamp, size, ev);
 				} else {
-					cerr << "Dropping incoming MIDI at time " << timestamp << "; offset="
-					     << _global_port_buffer_offset << " limit="
-					     << (_global_port_buffer_offset + _port_buffer_offset + nframes) << "\n";
+					_buffer->push_back (timestamp, size, buf);
 				}
 			}
 
diff --git a/libs/ardour/mididm.cc b/libs/ardour/mididm.cc
index 0888d154e9..0b95fc1bd5 100644
--- a/libs/ardour/mididm.cc
+++ b/libs/ardour/mididm.cc
@@ -37,7 +37,7 @@ MIDIDM::MIDIDM (framecnt_t sample_rate)
 }
 
 int64_t
-MIDIDM::parse_mclk (uint8_t* buf, pframes_t timestamp) const
+MIDIDM::parse_mclk (uint8_t const * const buf, pframes_t timestamp) const
 {
 	/* calculate time difference */
 #define MODCLK (16384)  // 1<<(2*7)
@@ -52,7 +52,7 @@ MIDIDM::parse_mclk (uint8_t* buf, pframes_t timestamp) const
 }
 
 int64_t
-MIDIDM::parse_mtc (uint8_t* buf, pframes_t timestamp) const
+MIDIDM::parse_mtc (uint8_t const * const buf, pframes_t timestamp) const
 {
 #define MODTC (2097152)  // 1<<(3*7)
 	const int64_t tc = (_monotonic_cnt + timestamp) & 0x001FFFFF;
@@ -101,7 +101,7 @@ int MIDIDM::process (pframes_t nframes, PortEngine &pe, void *midi_in, void *mid
 	for (pframes_t n = 0; n < nevents; ++n) {
 		pframes_t timestamp;
 		size_t size;
-		uint8_t* buf;
+		uint8_t const* buf;
 		int64_t tdiff;
 		pe.midi_event_get (timestamp, size, &buf, midi_in, n);