1 // Copyright 2020 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 #include <span> 18 #include <type_traits> 19 20 #include "pw_status/status_with_size.h" 21 22 namespace pw { 23 namespace internal { 24 25 template <typename T> 26 struct FunctionTraits; 27 28 template <typename T, typename ReturnType, typename... Args> 29 struct FunctionTraits<ReturnType (T::*)(Args...)> { 30 using Class = T; 31 using Return = ReturnType; 32 }; 33 34 } // namespace internal 35 36 // Writes bytes to an unspecified output. Provides a Write function that takes a 37 // std::span of bytes and returns a Status. 38 class Output { 39 public: 40 StatusWithSize Write(std::span<const std::byte> data) { 41 return DoWrite(data); 42 } 43 44 // Convenience wrapper for writing data from a pointer and length. 45 StatusWithSize Write(const void* data, size_t size_bytes) { 46 return Write(std::span<const std::byte>(static_cast<const std::byte*>(data), 47 size_bytes)); 48 } 49 50 protected: 51 ~Output() = default; 52 53 private: 54 virtual StatusWithSize DoWrite(std::span<const std::byte> data) = 0; 55 }; 56 57 class Input { 58 public: 59 StatusWithSize Read(std::span<std::byte> data) { return DoRead(data); } 60 61 // Convenience wrapper for reading data from a pointer and length. 62 StatusWithSize Read(void* data, size_t size_bytes) { 63 return Read( 64 std::span<std::byte>(static_cast<std::byte*>(data), size_bytes)); 65 } 66 67 protected: 68 ~Input() = default; 69 70 private: 71 virtual StatusWithSize DoRead(std::span<std::byte> data) = 0; 72 }; 73 74 // Output adapter that calls a free function. 75 class OutputToFunction final : public Output { 76 public: 77 OutputToFunction(StatusWithSize (*function)(std::span<const std::byte>)) 78 : function_(function) {} 79 80 private: 81 StatusWithSize DoWrite(std::span<const std::byte> data) override { 82 return function_(data); 83 } 84 85 StatusWithSize (*function_)(std::span<const std::byte>); 86 }; 87 88 } // namespace pw 89