text: /****************************************************************************
  **
  ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
  ** All rights reserved.
  ** Contact: Nokia Corporation (qt-info@nokia.com)
  **
  ** This file is part of the QtCore module of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:LGPL$
  ** GNU Lesser General Public License Usage
  ** This file may be used under the terms of the GNU Lesser General Public
  ** License version 2.1 as published by the Free Software Foundation and
  ** appearing in the file LICENSE.LGPL included in the packaging of this
  ** file. Please review the following information to ensure the GNU Lesser
  ** General Public License version 2.1 requirements will be met:
  ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
  **
  ** In addition, as a special exception, Nokia gives you certain additional
  ** rights. These rights are described in the Nokia Qt LGPL Exception
  ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
  **
  ** GNU General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU General
  ** Public License version 3.0 as published by the Free Software Foundation
  ** and appearing in the file LICENSE.GPL included in the packaging of this
  ** file. Please review the following information to ensure the GNU General
  ** Public License version 3.0 requirements will be met:
  ** http://www.gnu.org/copyleft/gpl.html.
  **
  ** Other Usage
  ** Alternatively, this file may be used in accordance with the terms and
  ** conditions contained in a signed written agreement between you and Nokia.
  **
  **
  **
  **
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/
  
  #ifndef QENDIAN_H
  #define QENDIAN_H
  
  #include <QtCore/qglobal.h>
  
  // include stdlib.h and hope that it defines __GLIBC__ for glibc-based systems
  #include <stdlib.h>
  
  #ifdef __GLIBC__
  #include <byteswap.h>
  #endif
  
  QT_BEGIN_HEADER
  
  QT_BEGIN_NAMESPACE
  
  QT_MODULE(Core)
  
  /*
   * ENDIAN FUNCTIONS
  */
  inline void qbswap_helper(const uchar *src, uchar *dest, int size)
  {
      for (int i = 0; i < size ; ++i) dest[i] = src[size - 1 - i];
  }
  
  /*
   * qbswap(const T src, const uchar *dest);
   * Changes the byte order of \a src from big endian to little endian or vice versa
   * and stores the result in \a dest.
   * There is no alignment requirements for \a dest.
  */
  template <typename T> inline void qbswap(const T src, uchar *dest)
  {
      qbswap_helper(reinterpret_cast<const uchar *>(&src), dest, sizeof(T));
  }
  
  // Used to implement a type-safe and alignment-safe copy operation
  // If you want to avoid the memcopy, you must write specializations for this function
  template <typename T> inline void qToUnaligned(const T src, uchar *dest)
  {
      qMemCopy(dest, &src, sizeof(T));
  }
  
  /* T qFromLittleEndian(const uchar *src)
   * This function will read a little-endian encoded value from \a src
   * and return the value in host-endian encoding.
   * There is no requirement that \a src must be aligned.
  */
  #if defined Q_CC_SUN
  inline quint64 qFromLittleEndian_helper(const uchar *src, quint64 *dest)
  {
      return 0
          | src[0]
          | src[1] * Q_UINT64_C(0x0000000000000100)
          | src[2] * Q_UINT64_C(0x0000000000010000)
          | src[3] * Q_UINT64_C(0x0000000001000000)
          | src[4] * Q_UINT64_C(0x0000000100000000)
          | src[5] * Q_UINT64_C(0x0000010000000000)
          | src[6] * Q_UINT64_C(0x0001000000000000)
          | src[7] * Q_UINT64_C(0x0100000000000000);
  }
  
  inline quint32 qFromLittleEndian_helper(const uchar *src, quint32 *dest)
  {
      return 0
          | src[0]
          | src[1] * quint32(0x00000100)
          | src[2] * quint32(0x00010000)
          | src[3] * quint32(0x01000000);
  }
  
  inline quint16 qFromLittleEndian_helper(const uchar *src, quint16 *dest)
  {
      return 0
          | src[0]
          | src[1] * 0x0100;
  }
  
  inline qint64 qFromLittleEndian_helper(const uchar *src, qint64 * dest)
  { return static_cast<qint64>(qFromLittleEndian_helper(src, reinterpret_cast<quint64*>(0))); }
  inline qint32 qFromLittleEndian_helper(const uchar *src, qint32 * dest)
  { return static_cast<qint32>(qFromLittleEndian_helper(src, reinterpret_cast<quint32*>(0))); }
  inline qint16 qFromLittleEndian_helper(const uchar *src, qint16 * dest)
  { return static_cast<qint16>(qFromLittleEndian_helper(src, reinterpret_cast<quint16*>(0))); }
  
  template <class T> inline T qFromLittleEndian(const uchar *src)
  {
      return qFromLittleEndian_helper(src, reinterpret_cast<T*>(0));
  }
  
  #else
  template <typename T> inline T qFromLittleEndian(const uchar *src);
  template <> inline quint64 qFromLittleEndian<quint64>(const uchar *src)
  {
      return 0
          | src[0]
          | src[1] * Q_UINT64_C(0x0000000000000100)
          | src[2] * Q_UINT64_C(0x0000000000010000)
          | src[3] * Q_UINT64_C(0x0000000001000000)
          | src[4] * Q_UINT64_C(0x0000000100000000)
          | src[5] * Q_UINT64_C(0x0000010000000000)
          | src[6] * Q_UINT64_C(0x0001000000000000)
          | src[7] * Q_UINT64_C(0x0100000000000000);
  }
  
  template <> inline quint32 qFromLittleEndian<quint32>(const uchar *src)
  {
      return 0
          | src[0]
          | src[1] * quint32(0x00000100)
          | src[2] * quint32(0x00010000)
          | src[3] * quint32(0x01000000);
  }
  
  template <> inline quint16 qFromLittleEndian<quint16>(const uchar *src)
  {
      return quint16(0
                     | src[0]
                     | src[1] * 0x0100);
  }
  
  // signed specializations
  template <> inline qint64 qFromLittleEndian<qint64>(const uchar *src)
  { return static_cast<qint64>(qFromLittleEndian<quint64>(src)); }
  
  template <> inline qint32 qFromLittleEndian<qint32>(const uchar *src)
  { return static_cast<qint32>(qFromLittleEndian<quint32>(src)); }
  
  template <> inline qint16 qFromLittleEndian<qint16>(const uchar *src)
  { return static_cast<qint16>(qFromLittleEndian<quint16>(src)); }
  #endif
  
  /* This function will read a big-endian (also known as network order) encoded value from \a src
   * and return the value in host-endian encoding.
   * There is no requirement that \a src must be aligned.
  */
  #if defined Q_CC_SUN
  inline quint64 qFromBigEndian_helper(const uchar *src, quint64 *dest)
  {
      return 0
          | src[7]
          | src[6] * Q_UINT64_C(0x0000000000000100)
          | src[5] * Q_UINT64_C(0x0000000000010000)
          | src[4] * Q_UINT64_C(0x0000000001000000)
          | src[3] * Q_UINT64_C(0x0000000100000000)
          | src[2] * Q_UINT64_C(0x0000010000000000)
          | src[1] * Q_UINT64_C(0x0001000000000000)
          | src[0] * Q_UINT64_C(0x0100000000000000);
  }
  
  inline quint32 qFromBigEndian_helper(const uchar *src, quint32 * dest)
  {
      return 0
          | src[3]
          | src[2] * quint32(0x00000100)
          | src[1] * quint32(0x00010000)
          | src[0] * quint32(0x01000000);
  }
  
  inline quint16 qFromBigEndian_helper(const uchar *src, quint16 * des)
  {
      return 0
          | src[1]
          | src[0] * 0x0100;
  }
  
  
  inline qint64 qFromBigEndian_helper(const uchar *src, qint64 * dest)
  { return static_cast<qint64>(qFromBigEndian_helper(src, reinterpret_cast<quint64*>(0))); }
  inline qint32 qFromBigEndian_helper(const uchar *src, qint32 * dest)
  { return static_cast<qint32>(qFromBigEndian_helper(src, reinterpret_cast<quint32*>(0))); }
  inline qint16 qFromBigEndian_helper(const uchar *src, qint16 * dest)
  { return static_cast<qint16>(qFromBigEndian_helper(src, reinterpret_cast<quint16*>(0))); }
  
  template <class T> inline T qFromBigEndian(const uchar *src)
  {
      return qFromBigEndian_helper(src, reinterpret_cast<T*>(0));
  }
  
  #else
  template <class T> inline T qFromBigEndian(const uchar *src);
  template<>
  inline quint64 qFromBigEndian<quint64>(const uchar *src)
  {
      return 0
          | src[7]
          | src[6] * Q_UINT64_C(0x0000000000000100)
          | src[5] * Q_UINT64_C(0x0000000000010000)
          | src[4] * Q_UINT64_C(0x0000000001000000)
          | src[3] * Q_UINT64_C(0x0000000100000000)
          | src[2] * Q_UINT64_C(0x0000010000000000)
          | src[1] * Q_UINT64_C(0x0001000000000000)
          | src[0] * Q_UINT64_C(0x0100000000000000);
  }
  
  template<>
  inline quint32 qFromBigEndian<quint32>(const uchar *src)
  {
      return 0
          | src[3]
          | src[2] * quint32(0x00000100)
          | src[1] * quint32(0x00010000)
          | src[0] * quint32(0x01000000);
  }
  
  template<>
  inline quint16 qFromBigEndian<quint16>(const uchar *src)
  {
      return quint16( 0
                      | src[1]
                      | src[0] * quint16(0x0100));
  }
  
  
  // signed specializations
  template <> inline qint64 qFromBigEndian<qint64>(const uchar *src)
  { return static_cast<qint64>(qFromBigEndian<quint64>(src)); }
  
  template <> inline qint32 qFromBigEndian<qint32>(const uchar *src)
  { return static_cast<qint32>(qFromBigEndian<quint32>(src)); }
  
  template <> inline qint16 qFromBigEndian<qint16>(const uchar *src)
  { return static_cast<qint16>(qFromBigEndian<quint16>(src)); }
  #endif
  /*
   * T qbswap(T source).
   * Changes the byte order of a value from big endian to little endian or vice versa.
   * This function can be used if you are not concerned about alignment issues,
   * and it is therefore a bit more convenient and in most cases more efficient.
  */
  template <typename T> T qbswap(T source);
  
  #ifdef __GLIBC__
  template <> inline quint64 qbswap<quint64>(quint64 source)
  {
      return bswap_64(source);
  }
  template <> inline quint32 qbswap<quint32>(quint32 source)
  {
      return bswap_32(source);
  }
  template <> inline quint16 qbswap<quint16>(quint16 source)
  {
      return bswap_16(source);
  }
  #else
  template <> inline quint64 qbswap<quint64>(quint64 source)
  {
      return 0
          | ((source & Q_UINT64_C(0x00000000000000ff)) << 56)
          | ((source & Q_UINT64_C(0x000000000000ff00)) << 40)
          | ((source & Q_UINT64_C(0x0000000000ff0000)) << 24)
          | ((source & Q_UINT64_C(0x00000000ff000000)) << 8)
          | ((source & Q_UINT64_C(0x000000ff00000000)) >> 8)
          | ((source & Q_UINT64_C(0x0000ff0000000000)) >> 24)
          | ((source & Q_UINT64_C(0x00ff000000000000)) >> 40)
          | ((source & Q_UINT64_C(0xff00000000000000)) >> 56);
  }
  
  template <> inline quint32 qbswap<quint32>(quint32 source)
  {
      return 0
          | ((source & 0x000000ff) << 24)
          | ((source & 0x0000ff00) << 8)
          | ((source & 0x00ff0000) >> 8)
          | ((source & 0xff000000) >> 24);
  }
  
  template <> inline quint16 qbswap<quint16>(quint16 source)
  {
      return quint16( 0
                      | ((source & 0x00ff) << 8)
                      | ((source & 0xff00) >> 8) );
  }
  #endif // __GLIBC__
  
  // signed specializations
  template <> inline qint64 qbswap<qint64>(qint64 source)
  {
      return qbswap<quint64>(quint64(source));
  }
  
  template <> inline qint32 qbswap<qint32>(qint32 source)
  {
      return qbswap<quint32>(quint32(source));
  }
  
  template <> inline qint16 qbswap<qint16>(qint16 source)
  {
      return qbswap<quint16>(quint16(source));
  }
  
  #if Q_BYTE_ORDER == Q_BIG_ENDIAN
  
  template <typename T> inline T qToBigEndian(T source)
  { return source; }
  template <typename T> inline T qFromBigEndian(T source)
  { return source; }
  template <typename T> inline T qToLittleEndian(T source)
  { return qbswap<T>(source); }
  template <typename T> inline T qFromLittleEndian(T source)
  { return qbswap<T>(source); }
  template <typename T> inline void qToBigEndian(T src, uchar *dest)
  { qToUnaligned<T>(src, dest); }
  template <typename T> inline void qToLittleEndian(T src, uchar *dest)
  { qbswap<T>(src, dest); }
  #else // Q_LITTLE_ENDIAN
  
  template <typename T> inline T qToBigEndian(T source)
  { return qbswap<T>(source); }
  template <typename T> inline T qFromBigEndian(T source)
  { return qbswap<T>(source); }
  template <typename T> inline T qToLittleEndian(T source)
  { return source; }
  template <typename T> inline T qFromLittleEndian(T source)
  { return source; }
  template <typename T> inline void qToBigEndian(T src, uchar *dest)
  { qbswap<T>(src, dest); }
  template <typename T> inline void qToLittleEndian(T src, uchar *dest)
  { qToUnaligned<T>(src, dest); }
  
  #endif // Q_BYTE_ORDER == Q_BIG_ENDIAN
  
  template <> inline quint8 qbswap<quint8>(quint8 source)
  {
      return source;
  }
  
  QT_END_NAMESPACE
  
  QT_END_HEADER
  
  #endif // QENDIAN_H
  