use struct pack as default

thirdparty/ylt/struct_pack/error_code.hpp

@@ -0,0 +1,84 @@
+/*
+ * 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