From 65f172a02e4d0dee1ca6163c33d03bc2e4474a9b Mon Sep 17 00:00:00 2001
From: Paul Ferrand <paul@ferrand.cc>
Date: Mon, 20 Jan 2020 19:09:31 +0100
Subject: [PATCH] Do a pseudo merge of events in the envelopes

---
 src/sfizz/EventEnvelopes.cpp | 32 +++++++++++++++++++++++++-------
 src/sfizz/EventEnvelopes.h   |  2 +-
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/src/sfizz/EventEnvelopes.cpp b/src/sfizz/EventEnvelopes.cpp
index f31d9978..4cd38f41 100644
--- a/src/sfizz/EventEnvelopes.cpp
+++ b/src/sfizz/EventEnvelopes.cpp
@@ -65,15 +65,33 @@ void EventEnvelope<Type>::registerEvent(int timestamp, Type inputValue)
 }
 
 template <class Type>
-void EventEnvelope<Type>::prepareEvents()
+void EventEnvelope<Type>::prepareEvents(int blockLength)
 {
     if (resetEvents)
         clear();
-
-    absl::c_sort(events, [](const auto& lhs, const auto& rhs) {
+    
+    absl::c_stable_sort(events, [](const auto& lhs, const auto& rhs) {
         return lhs.first < rhs.first;
     });
 
+    auto eventIt = events.begin();
+    while (eventIt < events.end()) {
+        if (eventIt->first >= blockLength) {
+            eventIt->first = blockLength - 1;
+            eventIt->second = events.back().second;
+            ++eventIt;
+            break;
+        }
+
+        auto nextEventIt = std::next(eventIt);
+        while (nextEventIt < events.end() && eventIt->first == nextEventIt->first ) {
+            eventIt->second = nextEventIt->second;
+            ++nextEventIt;
+        }
+        ++eventIt;
+    }
+    events.resize(std::distance(events.begin(), eventIt));
+    
     resetEvents = true;
 }
 
@@ -93,15 +111,15 @@ void EventEnvelope<Type>::reset(Type value)
 }
 
 template <class Type>
-void EventEnvelope<Type>::getBlock(absl::Span<Type>)
+void EventEnvelope<Type>::getBlock(absl::Span<Type> output)
 {
-    prepareEvents();
+    prepareEvents(output.size());
 }
 
 template <class Type>
-void EventEnvelope<Type>::getQuantizedBlock(absl::Span<Type>, Type)
+void EventEnvelope<Type>::getQuantizedBlock(absl::Span<Type> output, Type)
 {
-    prepareEvents();
+    prepareEvents(output.size());
 }
 
 template <class Type>
diff --git a/src/sfizz/EventEnvelopes.h b/src/sfizz/EventEnvelopes.h
index 883c887e..2115c82d 100644
--- a/src/sfizz/EventEnvelopes.h
+++ b/src/sfizz/EventEnvelopes.h
@@ -113,7 +113,7 @@ private:
     static_assert(std::is_arithmetic<Type>::value, "Type should be arithmetic");
     std::function<Type(Type)> function { [](Type input) { return input; } };
     int maxCapacity { config::defaultSamplesPerBlock };
-    void prepareEvents();
+    void prepareEvents(int blockLength);
     bool resetEvents { false };
     LEAK_DETECTOR(EventEnvelope);
 };