Add SparseVector::IndexAfter for efficiently finding elements in a range.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/SparseVector.h b/src/SparseVector.h
index e4e0e3f69..3fa1ac95b 100644
--- a/src/SparseVector.h
+++ b/src/SparseVector.h
@@ -154,6 +154,13 @@ public:
 		starts->InsertText(partition, -1);
 		Check();
 	}
+	Sci::Position IndexAfter(Sci::Position position) const noexcept {
+		assert(position < Length());
+		if (position < 0)
+			return 0;
+		const Sci::Position partition = starts->PartitionFromPosition(position);
+		return partition + 1;
+	}
 	void Check() const {
 #ifdef CHECK_CORRECTNESS
 		starts->Check();