AK: Add Endian.h header to replace NetworkOrdered.h.

AK/Endian.h

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Platform.h>
+
+namespace AK {
+
+template<typename T>
+ALWAYS_INLINE T convert_between_host_and_little_endian(T value)
+{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+    return value;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    if constexpr (sizeof(T) == 8)
+        return __builtin_bswap64(value);
+    if constexpr (sizeof(T) == 4)
+        return __builtin_bswap32(value);
+    if constexpr (sizeof(T) == 2)
+        return __builtin_bswap16(value);
+    if constexpr (sizeof(T) == 1)
+        return value;
+#endif
+}
+
+template<typename T>
+ALWAYS_INLINE T convert_between_host_and_big_endian(T value)
+{
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+    if constexpr (sizeof(T) == 8)
+        return __builtin_bswap64(value);
+    if constexpr (sizeof(T) == 4)
+        return __builtin_bswap32(value);
+    if constexpr (sizeof(T) == 2)
+        return __builtin_bswap16(value);
+    if constexpr (sizeof(T) == 1)
+        return value;
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    return value;
+#endif
+}
+
+template<typename T>
+ALWAYS_INLINE T convert_between_host_and_network_endian(T value)
+{
+    return convert_between_host_and_big_endian(value);
+}
+
+template<typename T>
+class [[gnu::packed]] LittleEndian
+{
+public:
+    LittleEndian() { }
+
+    LittleEndian(T value)
+        : m_value(convert_between_host_and_little_endian(value))
+    {
+    }
+
+    operator T() const { return convert_between_host_and_little_endian(m_value); }
+
+private:
+    T m_value { 0 };
+};
+
+template<typename T>
+class [[gnu::packed]] BigEndian
+{
+public:
+    BigEndian() { }
+
+    BigEndian(T value)
+        : m_value(convert_between_host_and_big_endian(value))
+    {
+    }
+
+    operator T() const { return convert_between_host_and_big_endian(m_value); }
+
+private:
+    T m_value { 0 };
+};
+
+template<typename T>
+using NetworkOrdered = BigEndian<T>;
+
+}
+
+using AK::BigEndian;
+using AK::LittleEndian;
+using AK::NetworkOrdered;