1 files changed, 68 insertions, 0 deletions
diff --git a/tensorflow/contrib/bigtable/kernels/bigtable_range_helpers.cc b/tensorflow/contrib/bigtable/kernels/bigtable_range_helpers.cc
new file mode 100644
index 0000000000..51965f6214
--- /dev/null
+++ b/tensorflow/contrib/bigtable/kernels/bigtable_range_helpers.cc
@@ -0,0 +1,68 @@
+/* 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.
+==============================================================================*/
+
+#include "tensorflow/contrib/bigtable/kernels/bigtable_range_helpers.h"
+
+#include "tensorflow/core/platform/logging.h"
+
+namespace tensorflow {
+
+namespace {
+
+string MakePrefixEndKey(const string& prefix) {
+  string end = prefix;
+  while (true) {
+    if (end.empty()) {
+      return end;
+    }
+    ++end[end.size() - 1];
+    if (end[end.size() - 1] == 0) {
+      // Handle wraparound case.
+      end = end.substr(0, end.size() - 1);
+    } else {
+      return end;
+    }
+  }
+}
+
+}  // namespace
+
+/* static */ MultiModeKeyRange MultiModeKeyRange::FromPrefix(string prefix) {
+  string end = MakePrefixEndKey(prefix);
+  VLOG(1) << "Creating MultiModeKeyRange from Prefix: " << prefix
+          << ", with end key: " << end;
+  return MultiModeKeyRange(std::move(prefix), std::move(end));
+}
+
+/* static */ MultiModeKeyRange MultiModeKeyRange::FromRange(string begin,
+                                                            string end) {
+  return MultiModeKeyRange(std::move(begin), std::move(end));
+}
+
+const string& MultiModeKeyRange::begin_key() const { return begin_; }
+
+const string& MultiModeKeyRange::end_key() const { return end_; }
+
+bool MultiModeKeyRange::contains_key(StringPiece key) const {
+  if (StringPiece(begin_) > key) {
+    return false;
+  }
+  if (StringPiece(end_) <= key && !end_.empty()) {
+    return false;
+  }
+  return true;
+}
+
+}  // namespace tensorflow