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-rwxr-xr-xCPP/7zip/Compress/ByteSwap.cpp73
1 files changed, 73 insertions, 0 deletions
diff --git a/CPP/7zip/Compress/ByteSwap.cpp b/CPP/7zip/Compress/ByteSwap.cpp
new file mode 100755
index 0000000..7f028fb
--- /dev/null
+++ b/CPP/7zip/Compress/ByteSwap.cpp
@@ -0,0 +1,73 @@
+// 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)