blob: b1f1658cbce122fc2c3197c8740e18e41baedc46 [file] [log] [blame]
// Copyright 2020 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
// 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_span/span.h"
#include "pw_status/status.h"
namespace pw::kvs {
class ChecksumAlgorithm {
// Resets the checksum to its initial state.
virtual void Reset() = 0;
// Updates the checksum with the provided data.
virtual void Update(span<const std::byte> data) = 0;
// Update the checksum from a pointer and size.
void Update(const void* data, size_t size_bytes) {
return Update(span(static_cast<const std::byte*>(data), size_bytes));
// Returns the current state of the checksum algorithm.
constexpr const span<const std::byte>& state() const { return state_; }
// Returns the size of the checksum state.
constexpr size_t size_bytes() const { return state_.size(); }
// Compares a calculated checksum to this checksum's current state. The
// checksum must be at least as large as size_bytes(). If it is larger, bytes
// beyond size_bytes() are ignored.
Status Verify(span<const std::byte> checksum) const;
// A derived class provides a span of its state buffer.
constexpr ChecksumAlgorithm(span<const std::byte> state) : state_(state) {}
// Protected destructor prevents deleting ChecksumAlgorithms from the base
// class, so that it is safe to have a non-virtual destructor.
~ChecksumAlgorithm() = default;
span<const std::byte> state_;
} // namespace pw::kvs