/*

 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef CPU_X86_VM_BYTES_X86_HPP

#define CPU_X86_VM_BYTES_X86_HPP

#include "memory/allocation.hpp"

#include "utilities/macros.hpp"

class Bytes: AllStatic {

 private:

#ifndef AMD64

  // Helper function for swap_u8

  static inline u8   swap_u8_base(u4 x, u4 y);        // compiler-dependent implementation

#endif // AMD64

 public:

  // Efficient reading and writing of unaligned unsigned data in platform-specific byte ordering

  template <typename T>

  static inline T get_native(const void* p) {

    assert(p != NULL, "null pointer");

    T x;

    if (is_aligned(p, sizeof(T))) {

      x = *(T*)p;

    } else {

      memcpy(&x, p, sizeof(T));

    }

    return x;

  }

  template <typename T>

  static inline void put_native(void* p, T x) {

    assert(p != NULL, "null pointer");

    if (is_aligned(p, sizeof(T))) {

      *(T*)p = x;

    } else {

      memcpy(p, &x, sizeof(T));

    }

  }

  static inline u2   get_native_u2(address p)         { return get_native<u2>((void*)p); }

  static inline u4   get_native_u4(address p)         { return get_native<u4>((void*)p); }

  static inline u8   get_native_u8(address p)         { return get_native<u8>((void*)p); }

  static inline void put_native_u2(address p, u2 x)   { put_native<u2>((void*)p, x); }

  static inline void put_native_u4(address p, u4 x)   { put_native<u4>((void*)p, x); }

  static inline void put_native_u8(address p, u8 x)   { put_native<u8>((void*)p, x); }

  // Efficient reading and writing of unaligned unsigned data in Java

  // byte ordering (i.e. big-endian ordering). Byte-order reversal is

  // needed since x86 CPUs use little-endian format.

  template <typename T>

  static inline T get_Java(const address p) {

    T x = get_native<T>(p);

    if (Endian::is_Java_byte_ordering_different()) {

      x = swap<T>(x);

    }

    return x;

  }

  template <typename T>

  static inline void put_Java(address p, T x) {

    if (Endian::is_Java_byte_ordering_different()) {

      x = swap<T>(x);

    }

    put_native<T>(p, x);

  }

  static inline u2   get_Java_u2(address p)           { return get_Java<u2>(p); }

  static inline u4   get_Java_u4(address p)           { return get_Java<u4>(p); }

  static inline u8   get_Java_u8(address p)           { return get_Java<u8>(p); }

  static inline void put_Java_u2(address p, u2 x)     { put_Java<u2>(p, x); }

  static inline void put_Java_u4(address p, u4 x)     { put_Java<u4>(p, x); }

  static inline void put_Java_u8(address p, u8 x)     { put_Java<u8>(p, x); }

  // Efficient swapping of byte ordering

  template <typename T>

  static T swap(T x) {

    switch (sizeof(T)) {

    case sizeof(u1): return x;

    case sizeof(u2): return swap_u2(x);

    case sizeof(u4): return swap_u4(x);

    case sizeof(u8): return swap_u8(x);

    default:

      guarantee(false, "invalid size: " SIZE_FORMAT "\n", sizeof(T));

      return 0;

    }

  }

  static inline u2   swap_u2(u2 x);                   // compiler-dependent implementation

  static inline u4   swap_u4(u4 x);                   // compiler-dependent implementation

  static inline u8   swap_u8(u8 x);

};

// The following header contains the implementations of swap_u2, swap_u4, and swap_u8[_base]

#include OS_CPU_HEADER_INLINE(bytes)

#endif // CPU_X86_VM_BYTES_X86_HPP