Fix seek in linearly interpolated control lists.

diff --git a/libs/evoral/src/ControlList.cpp b/libs/evoral/src/ControlList.cpp
index 70500ba8de0319e0e56b40574dcc9000dd04f7eb..902a20980ebd4deb876c3b5dbc2f8f632ceee7b7 100644 (file)
--- a/libs/evoral/src/ControlList.cpp
+++ b/libs/evoral/src/ControlList.cpp
@@ -1242,21 +1242,27 @@ ControlList::multipoint_eval (double x) const
 void
 ControlList::build_search_cache_if_necessary (double start) const
 {
-       /* Only do the range lookup if x is in a different range than last time
-        * this was called (or if the search cache has been marked "dirty" (left<0) */
        if (_events.empty()) {
+               /* Empty, nothing to cache, move to end. */
                _search_cache.first = _events.end();
                _search_cache.left = 0;
+               return;
        } else if ((_search_cache.left < 0) || (_search_cache.left > start)) {
+               /* Marked dirty (left < 0), or we're too far forward, re-search. */
 
                const ControlEvent start_point (start, 0);
 
-               //cerr << "REBUILD: (" << _search_cache.left << ".." << _search_cache.right << ") := ("
-               //      << start << ".." << end << ")" << endl;
-
                _search_cache.first = lower_bound (_events.begin(), _events.end(), &start_point, time_comparator);
                _search_cache.left = start;
        }
+
+       /* We now have a search cache that is not too far right, but it may be too
+          far left and need to be advanced. */
+
+       while (_search_cache.first != end() && (*_search_cache.first)->when < start) {
+               ++_search_cache.first;
+       }
+       _search_cache.left = start;
 }
 
 /** Get the earliest event after \a start using the current interpolation style.
@@ -1365,8 +1371,8 @@ ControlList::rt_safe_earliest_event_linear_unlocked (double start, double& x, do
                const ControlEvent* first = NULL;
                const ControlEvent* next = NULL;
 
-               /* Step is after first */
                if (_search_cache.first == _events.begin() || (*_search_cache.first)->when <= start) {
+                       /* Step is after first */
                        first = *_search_cache.first;
                        ++_search_cache.first;
                        if (_search_cache.first == _events.end()) {
@@ -1374,8 +1380,8 @@ ControlList::rt_safe_earliest_event_linear_unlocked (double start, double& x, do
                        }
                        next = *_search_cache.first;
 
-                       /* Step is before first */
                } else {
+                       /* Step is before first */
                        const_iterator prev = _search_cache.first;
                        --prev;
                        first = *prev;
@@ -1455,8 +1461,8 @@ ControlList::rt_safe_earliest_event_linear_unlocked (double start, double& x, do
                        return true;
                }
 
-               /* No points in the future, so no steps (towards them) in the future */
        } else {
+               /* No points in the future, so no steps (towards them) in the future */
                return false;
        }
 }