1 // ByteSwap.cpp

     2 

     3 #include "StdAfx.h"

     4 

     5 #include "ByteSwap.h"

     6 

     7 STDMETHODIMP CByteSwap2::Init() { return S_OK; }

     8 

     9 STDMETHODIMP_(UInt32) CByteSwap2::Filter(Byte *data, UInt32 size)

    10 {

    11   const UInt32 kStep = 2;

    12   UInt32 i;

    13   for (i = 0; i + kStep <= size; i += kStep)

    14   {

    15     Byte b = data[i];

    16     data[i] = data[i + 1];

    17     data[i + 1] = b;

    18   }

    19   return i;

    20 }

    21 

    22 STDMETHODIMP CByteSwap4::Init() { return S_OK; }

    23 

    24 STDMETHODIMP_(UInt32) CByteSwap4::Filter(Byte *data, UInt32 size)

    25 {

    26   const UInt32 kStep = 4;

    27   UInt32 i;

    28   for (i = 0; i + kStep <= size; i += kStep)

    29   {

    30     Byte b0 = data[i];

    31     Byte b1 = data[i + 1];

    32     data[i] = data[i + 3];

    33     data[i + 1] = data[i + 2];

    34     data[i + 2] = b1;

    35     data[i + 3] = b0;

    36   }

    37   return i;

    38 }