1 // Copyright 2021 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <cstddef> 17 18 #include "pw_bytes/span.h" 19 #include "pw_result/result.h" 20 #include "pw_span/span.h" 21 22 namespace pw::snapshot { 23 24 // Snapshot UUIDs are expected to be 128-bit. 25 // 26 // Note this is not strictly enforced anywhere, this is pure for convenience. 27 inline constexpr size_t kUuidSizeBytes = 16; 28 29 using UuidSpan = span<std::byte, kUuidSizeBytes>; 30 using ConstUuidSpan = span<const std::byte, kUuidSizeBytes>; 31 32 // Reads the snapshot UUID from an in memory snapshot, if present, and returns 33 // the subspan of `output` that contains the read snapshot. 34 // 35 // Returns: 36 // OK - UUID found, status with size indicates number of bytes written to 37 // `output`. 38 // RESOURCE_EXHUASTED - UUID found, but `output` was too small to fit it. 39 // NOT_FOUND - No snapshot UUID found in the provided snapshot. 40 Result<ConstByteSpan> ReadUuidFromSnapshot(ConstByteSpan snapshot, 41 UuidSpan output); 42 43 } // namespace pw::snapshot 44