gecko/modules/lib7z/LZMASDK/CPP/7zip/Compress/ByteSwap.cpp

74 lines
1.5 KiB
C++

// ByteSwap.cpp
#include "StdAfx.h"
#include "../../Common/MyCom.h"
#include "../ICoder.h"
#include "../Common/RegisterCodec.h"
class CByteSwap2:
public ICompressFilter,
public CMyUnknownImp
{
public:
MY_UNKNOWN_IMP
STDMETHOD(Init)();
STDMETHOD_(UInt32, Filter)(Byte *data, UInt32 size);
};
class CByteSwap4:
public ICompressFilter,
public CMyUnknownImp
{
public:
MY_UNKNOWN_IMP
STDMETHOD(Init)();
STDMETHOD_(UInt32, Filter)(Byte *data, UInt32 size);
};
STDMETHODIMP CByteSwap2::Init() { return S_OK; }
STDMETHODIMP_(UInt32) CByteSwap2::Filter(Byte *data, UInt32 size)
{
const UInt32 kStep = 2;
UInt32 i;
for (i = 0; i + kStep <= size; i += kStep)
{
Byte b = data[i];
data[i] = data[i + 1];
data[i + 1] = b;
}
return i;
}
STDMETHODIMP CByteSwap4::Init() { return S_OK; }
STDMETHODIMP_(UInt32) CByteSwap4::Filter(Byte *data, UInt32 size)
{
const UInt32 kStep = 4;
UInt32 i;
for (i = 0; i + kStep <= size; i += kStep)
{
Byte b0 = data[i];
Byte b1 = data[i + 1];
data[i] = data[i + 3];
data[i + 1] = data[i + 2];
data[i + 2] = b1;
data[i + 3] = b0;
}
return i;
}
static void *CreateCodec2() { return (void *)(ICompressFilter *)(new CByteSwap2); }
static void *CreateCodec4() { return (void *)(ICompressFilter *)(new CByteSwap4); }
static CCodecInfo g_CodecsInfo[] =
{
{ CreateCodec2, CreateCodec2, 0x020302, L"Swap2", 1, true },
{ CreateCodec4, CreateCodec4, 0x020304, L"Swap4", 1, true }
};
REGISTER_CODECS(ByteSwap)