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+/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#ifndef TENSORFLOW_CONTRIB_BIGTABLE_KERNELS_BIGTABLE_RANGE_HELPERS_H_
+#define TENSORFLOW_CONTRIB_BIGTABLE_KERNELS_BIGTABLE_RANGE_HELPERS_H_
+
+#include <string>
+
+#include "tensorflow/core/lib/core/stringpiece.h"
+#include "tensorflow/core/platform/types.h"
+
+namespace tensorflow {
+
+// Represents a continuous range of keys defined by either a prefix or a range.
+//
+// Ranges are represented as "half-open", where the beginning key is included
+// in the range, and the end_key is the first excluded key after the range.
+//
+// The range of keys can be specified either by a key prefix, or by an explicit
+// begin key and end key. All methods on this class are valid no matter which
+// way the range was specified.
+//
+// Example:
+//   MultiModeKeyRange range = MultiModeKeyRange::FromPrefix("myPrefix");
+//   if (range.contains_key("myPrefixedKey")) {
+//     LOG(INFO) << "range from " << range.begin_key() << " to "
+//               << range.end_key() << "contains \"myPrefixedKey\"";
+//   }
+//   if (!range.contains_key("randomKey")) {
+//     LOG(INFO) << "range does not contain \"randomKey\"";
+//   }
+//   range = MultiModeKeyRange::FromRange("a_start_key", "z_end_key");
+class MultiModeKeyRange {
+ public:
+  static MultiModeKeyRange FromPrefix(string prefix);
+  static MultiModeKeyRange FromRange(string begin, string end);
+
+  // The first valid key in the range.
+  const string& begin_key() const;
+  // The first invalid key after the valid range.
+  const string& end_key() const;
+  // Returns true if the provided key is a part of the range, false otherwise.
+  bool contains_key(StringPiece key) const;
+
+ private:
+  MultiModeKeyRange(string begin, string end)
+      : begin_(std::move(begin)), end_(std::move(end)) {}
+
+  const string begin_;
+  const string end_;
+};
+
+}  // namespace tensorflow
+
+#endif  // TENSORFLOW_CONTRIB_BIGTABLE_KERNELS_BIGTABLE_RANGE_HELPERS_H_