1 files changed, 72 insertions, 0 deletions
diff --git a/icing/store/namespace-fingerprint-identifier.h b/icing/store/namespace-fingerprint-identifier.h
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+++ b/icing/store/namespace-fingerprint-identifier.h
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+// Copyright (C) 2023 Google LLC
+//
+// 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 ICING_STORE_NAMESPACE_FINGERPRINT_IDENTIFIER_H_
+#define ICING_STORE_NAMESPACE_FINGERPRINT_IDENTIFIER_H_
+
+#include <cstdint>
+#include <string>
+#include <string_view>
+
+#include "icing/text_classifier/lib3/utils/base/statusor.h"
+#include "icing/store/namespace-id.h"
+
+namespace icing {
+namespace lib {
+
+class NamespaceFingerprintIdentifier {
+ public:
+  static constexpr int kEncodedNamespaceIdLength = 3;
+  static constexpr int kMinEncodedLength = kEncodedNamespaceIdLength + 1;
+
+  static libtextclassifier3::StatusOr<NamespaceFingerprintIdentifier>
+  DecodeFromCString(std::string_view encoded_cstr);
+
+  explicit NamespaceFingerprintIdentifier()
+      : namespace_id_(0), fingerprint_(0) {}
+
+  explicit NamespaceFingerprintIdentifier(NamespaceId namespace_id,
+                                          uint64_t fingerprint)
+      : namespace_id_(namespace_id), fingerprint_(fingerprint) {}
+
+  explicit NamespaceFingerprintIdentifier(NamespaceId namespace_id,
+                                          std::string_view target_str);
+
+  std::string EncodeToCString() const;
+
+  bool operator<(const NamespaceFingerprintIdentifier& other) const {
+    if (namespace_id_ != other.namespace_id_) {
+      return namespace_id_ < other.namespace_id_;
+    }
+    return fingerprint_ < other.fingerprint_;
+  }
+
+  bool operator==(const NamespaceFingerprintIdentifier& other) const {
+    return namespace_id_ == other.namespace_id_ &&
+           fingerprint_ == other.fingerprint_;
+  }
+
+  NamespaceId namespace_id() const { return namespace_id_; }
+  uint64_t fingerprint() const { return fingerprint_; }
+
+ private:
+  NamespaceId namespace_id_;
+  uint64_t fingerprint_;
+} __attribute__((packed));
+static_assert(sizeof(NamespaceFingerprintIdentifier) == 10, "");
+
+}  // namespace lib
+}  // namespace icing
+
+#endif  // ICING_STORE_NAMESPACE_FINGERPRINT_IDENTIFIER_H_