add endian.h

Author: HeartLinked

src/iceberg/util/endian.h

@@ -0,0 +1,76 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 <array>
+#include <bit>
+#include <concepts>
+
+/// \file iceberg/util/endian.h
+/// \brief Endianness conversion utilities
+
+namespace iceberg {
+
+/// \brief Concept for values that can be written in little-endian format.
+template <typename T>
+concept EndianConvertible = std::is_arithmetic_v<T>;
+
+/// \brief Concept for values that can be written in big-endian format,
+template <typename T>
+concept BigEndianWritable = std::same_as<T, std::array<uint8_t, 16>>;
+
+/// \brief Convert a value to little-endian format.
+template <EndianConvertible T>
+T ToLittleEndian(T value) {
+  if constexpr (std::endian::native != std::endian::little && sizeof(T) > 1) {
+    return std::byteswap(value);
+  }
+  return value;
+}
+
+/// \brief Convert a value from little-endian format.
+template <EndianConvertible T>
+T FromLittleEndian(T value) {
+  if constexpr (std::endian::native != std::endian::little && sizeof(T) > 1) {
+    return std::byteswap(value);
+  }
+  return value;
+}
+
+template <EndianConvertible T>
+constexpr T ToBigEndian(T value) {
+  if constexpr (std::endian::native == std::endian::big || sizeof(T) <= 1) {
+    return value;
+  } else {
+    return std::byteswap(value);
+  }
+}
+
+/// \brief Convert a value from big-endian format to native.
+template <EndianConvertible T>
+constexpr T FromBigEndian(T value) {
+  if constexpr (std::endian::native == std::endian::big || sizeof(T) <= 1) {
+    return value;
+  } else {
+    return std::byteswap(value);
+  }
+}
+
+}  // namespace iceberg