cont’d work on a16dd7c, fixes #6170

[ardour.git] / libs / ardour / midi_ring_buffer.cc

diff --git a/libs/ardour/midi_ring_buffer.cc b/libs/ardour/midi_ring_buffer.cc
index 9fbd9dfdff78183d683c495160a3289261954857..5bd3f947e27ad6ace2fe33769b93bb598791ea92 100644 (file)
--- a/libs/ardour/midi_ring_buffer.cc
+++ b/libs/ardour/midi_ring_buffer.cc
@@ -60,6 +60,10 @@ MidiRingBuffer<T>::read(MidiBuffer& dst, framepos_t start, framepos_t end, frame
                ev_time = *(reinterpret_cast<T*>((uintptr_t)peekbuf));
                ev_size = *(reinterpret_cast<uint32_t*>((uintptr_t)(peekbuf + sizeof(T) + sizeof (Evoral::EventType))));
 
+               if (this->read_space() < ev_size) {
+                       break;;
+               }
+
                if (ev_time >= end) {
                        DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("MRB event @ %1 past end @ %2\n", ev_time, end));
                        break;
@@ -124,6 +128,59 @@ MidiRingBuffer<T>::read(MidiBuffer& dst, framepos_t start, framepos_t end, frame
        return count;
 }
 
+template<typename T>
+size_t
+MidiRingBuffer<T>::skip_to(framepos_t start)
+{
+       if (this->read_space() == 0) {
+               return 0;
+       }
+
+       T                 ev_time;
+       uint32_t          ev_size;
+       size_t            count = 0;
+       const size_t      prefix_size = sizeof(T) + sizeof(Evoral::EventType) + sizeof(uint32_t);
+
+       while (this->read_space() >= prefix_size) {
+
+               uint8_t peekbuf[prefix_size];
+               this->peek (peekbuf, prefix_size);
+
+               ev_time = *(reinterpret_cast<T*>((uintptr_t)peekbuf));
+               ev_size = *(reinterpret_cast<uint32_t*>((uintptr_t)(peekbuf + sizeof(T) + sizeof (Evoral::EventType))));
+
+               if (ev_time >= start) {
+                       return count;
+               }
+
+               if (this->read_space() < ev_size) {
+                       continue;
+               }
+
+               this->increment_read_ptr (prefix_size);
+
+               uint8_t status;
+               bool r = this->peek (&status, sizeof(uint8_t));
+               assert (r); // If this failed, buffer is corrupt, all hope is lost
+
+               ++count;
+
+               if (ev_size < 8) {
+                       this->increment_read_ptr (ev_size);
+               } else {
+                       // we only track note on/off, 8 bytes are plenty.
+                       uint8_t write_loc[8];
+                       bool success = read_contents (ev_size, write_loc);
+                       if (success) {
+                               _tracker.track(write_loc);
+                       }
+               }
+       }
+       return count;
+}
+
+
+
 template<typename T>
 void
 MidiRingBuffer<T>::flush (framepos_t /*start*/, framepos_t end)