| // 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 |
| // |
| // 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 <type_traits> |
| |
| #include "pw_span/span.h" |
| #include "pw_status/status_with_size.h" |
| |
| namespace pw { |
| namespace internal { |
| |
| template <typename T> |
| struct FunctionTraits; |
| |
| template <typename T, typename ReturnType, typename... Args> |
| struct FunctionTraits<ReturnType (T::*)(Args...)> { |
| using Class = T; |
| using Return = ReturnType; |
| }; |
| |
| } // namespace internal |
| |
| // Writes bytes to an unspecified output. Provides a Write function that takes a |
| // span of bytes and returns a Status. |
| class Output { |
| public: |
| virtual StatusWithSize Write(span<const std::byte> data) = 0; |
| |
| // Convenience wrapper for writing data from a pointer and length. |
| StatusWithSize Write(const void* data, size_t size_bytes) { |
| return Write(span(static_cast<const std::byte*>(data), size_bytes)); |
| } |
| |
| protected: |
| ~Output() = default; |
| }; |
| |
| // Output adapter that calls a method on a class with a span of bytes. If the |
| // method returns void instead of the expected Status, Write always returns |
| // Status::OK. |
| template <auto kMethod> |
| class OutputToMethod final : public Output { |
| using Class = typename internal::FunctionTraits<decltype(kMethod)>::Class; |
| |
| public: |
| constexpr OutputToMethod(Class* object) : object_(*object) {} |
| |
| StatusWithSize Write(span<const std::byte> data) override { |
| using Return = typename internal::FunctionTraits<decltype(kMethod)>::Return; |
| |
| if constexpr (std::is_void_v<Return>) { |
| (object_.*kMethod)(data); |
| return StatusWithSize(data.size()); |
| } else { |
| return (object_.*kMethod)(data); |
| } |
| } |
| |
| private: |
| Class& object_; |
| }; |
| |
| // Output adapter that calls a free function. |
| class OutputToFunction final : public Output { |
| public: |
| OutputToFunction(StatusWithSize (*function)(span<const std::byte>)) |
| : function_(function) {} |
| |
| StatusWithSize Write(span<const std::byte> data) override { |
| return function_(data); |
| } |
| |
| StatusWithSize (*function_)(span<const std::byte>); |
| }; |
| |
| } // namespace pw |