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Diffstat (limited to 'icing/store/namespace-fingerprint-identifier.cc')
-rw-r--r-- | icing/store/namespace-fingerprint-identifier.cc | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/icing/store/namespace-fingerprint-identifier.cc b/icing/store/namespace-fingerprint-identifier.cc new file mode 100644 index 0000000..3910105 --- /dev/null +++ b/icing/store/namespace-fingerprint-identifier.cc @@ -0,0 +1,73 @@ +// 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. + +#include "icing/store/namespace-fingerprint-identifier.h" + +#include <cstdint> +#include <string> +#include <string_view> + +#include "icing/text_classifier/lib3/utils/base/statusor.h" +#include "icing/text_classifier/lib3/utils/hash/farmhash.h" +#include "icing/absl_ports/canonical_errors.h" +#include "icing/absl_ports/str_cat.h" +#include "icing/store/namespace-id.h" +#include "icing/util/encode-util.h" + +namespace icing { +namespace lib { + +/* static */ libtextclassifier3::StatusOr<NamespaceFingerprintIdentifier> +NamespaceFingerprintIdentifier::DecodeFromCString( + std::string_view encoded_cstr) { + if (encoded_cstr.size() < kMinEncodedLength) { + return absl_ports::InvalidArgumentError("Invalid length"); + } + + NamespaceId namespace_id = encode_util::DecodeIntFromCString( + encoded_cstr.substr(0, kEncodedNamespaceIdLength)); + uint64_t fingerprint = encode_util::DecodeIntFromCString( + encoded_cstr.substr(kEncodedNamespaceIdLength)); + return NamespaceFingerprintIdentifier(namespace_id, fingerprint); +} + +NamespaceFingerprintIdentifier::NamespaceFingerprintIdentifier( + NamespaceId namespace_id, std::string_view target_str) + : namespace_id_(namespace_id), + fingerprint_(tc3farmhash::Fingerprint64(target_str)) {} + +std::string NamespaceFingerprintIdentifier::EncodeToCString() const { + // encoded_namespace_id_str should be 1 to 3 bytes based on the value of + // namespace_id. + std::string encoded_namespace_id_str = + encode_util::EncodeIntToCString(namespace_id_); + // Make encoded_namespace_id_str to fixed kEncodedNamespaceIdLength bytes. + while (encoded_namespace_id_str.size() < kEncodedNamespaceIdLength) { + // C string cannot contain 0 bytes, so we append it using 1, just like what + // we do in encode_util::EncodeIntToCString. + // + // The reason that this works is because DecodeIntToString decodes a byte + // value of 0x01 as 0x00. When EncodeIntToCString returns an encoded + // namespace id that is less than 3 bytes, it means that the id contains + // unencoded leading 0x00. So here we're explicitly encoding those bytes as + // 0x01. + encoded_namespace_id_str.push_back(1); + } + + return absl_ports::StrCat(encoded_namespace_id_str, + encode_util::EncodeIntToCString(fingerprint_)); +} + +} // namespace lib +} // namespace icing |