intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 48 insertions, 0 deletions

diff --git a/util/digest/sequence.h b/util/digest/sequence.h
new file mode 100644
index 00000000000..712331007b8
--- /dev/null
+++ b/util/digest/sequence.h
@@ -0,0 +1,48 @@
+#pragma once
+
+#include "numeric.h"
+#include <util/generic/hash.h>
+#include <util/generic/array_ref.h>
+
+template <typename ElementHash = void>
+class TRangeHash {
+private:
+    template <typename ElementType>
+    using TBase = std::conditional_t<
+        !std::is_void<ElementHash>::value,
+        ElementHash,
+        THash<ElementType>>;
+
+public:
+    template <typename Range>
+    size_t operator()(const Range& range) const {
+        size_t accumulated = 0;
+        for (const auto& element : range) {
+            accumulated = CombineHashes(accumulated, TBase<typename Range::value_type>()(element));
+        }
+        return accumulated;
+    }
+};
+
+using TSimpleRangeHash = TRangeHash<>;
+
+template <typename RegionHash = void>
+class TContiguousHash {
+private:
+    template <typename ElementType>
+    using TBase = std::conditional_t<
+        !std::is_void<RegionHash>::value,
+        RegionHash,
+        TRangeHash<ElementType>>;
+
+public:
+    template <typename ContainerType>
+    auto operator()(const ContainerType& container) const {
+        return operator()(MakeArrayRef(container));
+    }
+
+    template <typename ElementType>
+    auto operator()(const TArrayRef<ElementType>& data) const {
+        return TBase<ElementType>()(data);
+    }
+};