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// Copyright 2021 The Pigweed Authors
//
// 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
//
// https://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.
#pragma once
#include <cstddef>
#include "pw_preprocessor/compiler.h"
namespace pw::blob_store::internal {
enum MetadataVersion : uint32_t {
// Original metadata format does not include a version.
kVersion1 = 0,
kVersion2 = 0x1197851D,
kLatest = kVersion2
};
// Technically the original BlobMetadataV1 was not packed.
PW_PACKED(struct) BlobMetadataV1 {
typedef uint32_t ChecksumValue;
// The checksum of the blob data stored in flash.
ChecksumValue checksum;
// Number of blob data bytes stored in flash.
// Technically this was originally size_t, but backwards compatibility for
// platform-specific sized types has been dropped.
uint32_t data_size_bytes;
};
// Changes to the metadata format should also get a different key signature to
// avoid new code improperly reading old format metadata.
PW_PACKED(struct) BlobMetadataHeaderV2 {
BlobMetadataV1 v1_metadata;
// Metadata encoding version stored in flash.
MetadataVersion version;
// Length of the file name stored in the metadata entry.
uint8_t file_name_length;
// Following this struct is file_name_length chars of file name. Note that
// the string of characters is NOT null terminated.
constexpr void reset() {
*this = {
.v1_metadata =
{
.checksum = 0,
.data_size_bytes = 0,
},
.version = MetadataVersion::kLatest,
.file_name_length = 0,
};
}
};
using BlobMetadataHeader = BlobMetadataHeaderV2;
using ChecksumValue = BlobMetadataV1::ChecksumValue;
} // namespace pw::blob_store::internal
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