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 <type_traits> 18 19 #include "pw_span/span.h" 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 // span of bytes and returns a Status. 38 class Output { 39 public: 40 StatusWithSize Write(span<const std::byte> data) { return DoWrite(data); } 41 42 // Convenience wrapper for writing data from a pointer and length. 43 StatusWithSize Write(const void* data, size_t size_bytes) { 44 return Write( 45 span<const std::byte>(static_cast<const std::byte*>(data), size_bytes)); 46 } 47 48 protected: 49 ~Output() = default; 50 51 private: 52 virtual StatusWithSize DoWrite(span<const std::byte> data) = 0; 53 }; 54 55 class Input { 56 public: 57 StatusWithSize Read(span<std::byte> data) { return DoRead(data); } 58 59 // Convenience wrapper for reading data from a pointer and length. 60 StatusWithSize Read(void* data, size_t size_bytes) { 61 return Read(span<std::byte>(static_cast<std::byte*>(data), size_bytes)); 62 } 63 64 protected: 65 ~Input() = default; 66 67 private: 68 virtual StatusWithSize DoRead(span<std::byte> data) = 0; 69 }; 70 71 // Output adapter that calls a free function. 72 class OutputToFunction final : public Output { 73 public: 74 OutputToFunction(StatusWithSize (*function)(span<const std::byte>)) 75 : function_(function) {} 76 77 private: 78 StatusWithSize DoWrite(span<const std::byte> data) override { 79 return function_(data); 80 } 81 82 StatusWithSize (*function_)(span<const std::byte>); 83 }; 84 85 } // namespace pw 86