preparing update of physfs

jni/physfs-2.0.3/lzma/CPP/7zip/Compress/ByteSwap/ByteSwap.cpp

@@ -0,0 +1,38 @@
+// ByteSwap.cpp
+
+#include "StdAfx.h"
+
+#include "ByteSwap.h"
+
+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;
+}