1 files changed, 30 insertions, 0 deletions
diff --git a/lib/core/c++/index.hpp b/lib/core/c++/index.hpp
new file mode 100644
index 0000000..00e597e
--- /dev/null
+++ b/lib/core/c++/index.hpp
@@ -0,0 +1,30 @@
+#pragma once
+
+#include "common.hpp"
+
+namespace kel {
+namespace lbm {
+
+template<typename T, uint64_t D>
+saw::data<sch::FixedArray<sch::UInt64,D>> lower_index_from_pos(const saw::data<sch::Vector<T,D>>& pos){
+	saw::data<sch::FixedArray<sch::UInt64,D>> ind;
+
+	for(saw::data<sch::UInt64> i{0u}; i < ind.size(); ++i){
+		ind.at(i).set(std::max(pos.at(i).template cast_to<sch::UInt64>().get(),0));
+	}
+
+	return ind;
+}
+
+template<typename T, uint64_t D>
+saw::data<sch::FixedArray<sch::UInt64,D>> upper_index_from_pos(const saw::data<sch::Vector<T,D>>& pos){
+	auto ind = lower_index_from_pos(pos);
+
+	for(saw::data<sch::UInt64> i{0u}; i < ind.size(); ++i){
+		++ind.at(i);
+	}
+	return ind;
+}
+
+}
+}