include/ylt/struct_pack/error_code.hpp

/*
 * Copyright (c) 2023, Alibaba Group Holding Limited;
 *
 * 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
 *
 *     http://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 <system_error>

namespace struct_pack {
enum class errc {
  ok = 0,
  no_buffer_space,
  invalid_buffer,
  hash_conflict,
  invalid_width_of_container_length,
};
namespace detail {
inline constexpr std::string_view make_error_message(errc ec) noexcept {
  switch (ec) {
    case errc::ok:
      return "ok";
    case errc::no_buffer_space:
      return "no buffer space";
    case errc::invalid_buffer:
      return "invalid argument";
    case errc::hash_conflict:
      return "hash conflict";
    case errc::invalid_width_of_container_length:
      return "invalid width of container length";
    default:
      return "(unrecognized error)";
  }
}
}  // namespace detail

struct err_code {
 public:
  errc ec;
  constexpr err_code() noexcept : ec(errc::ok) {}
  constexpr err_code(errc ec) noexcept : ec(ec){};
  constexpr err_code& operator=(errc ec) noexcept {
    this->ec = ec;
    return *this;
  }
  constexpr err_code(const err_code& err_code) noexcept = default;
  constexpr err_code& operator=(const err_code& o) noexcept = default;
  constexpr operator errc() const noexcept { return ec; }
  constexpr operator bool() const noexcept { return ec != errc::ok; }
  constexpr int val() const noexcept { return static_cast<int>(ec); }
  constexpr std::string_view message() const noexcept {
    return detail::make_error_message(ec);
  }
};

namespace detail {
class struct_pack_category : public std::error_category {
 public:
  virtual const char* name() const noexcept override {
    return "struct_pack::category";
  }

  virtual std::string message(int err_val) const override {
    return std::string{make_error_message(static_cast<errc>(err_val))};
  }
};

inline const std::error_category& category() {
  static struct_pack::detail::struct_pack_category instance;
  return instance;
}
}  // namespace detail

}  // namespace struct_pack