1 files changed, 38 insertions, 24 deletions

diff --git a/CPP/7zip/Compress/ByteSwap.cpp b/CPP/7zip/Compress/ByteSwap.cpp
index 645b6ffc..f5620d6c 100644
--- a/CPP/7zip/Compress/ByteSwap.cpp
+++ b/CPP/7zip/Compress/ByteSwap.cpp
@@ -14,8 +14,7 @@ class CByteSwap2:
 {
 public:
   MY_UNKNOWN_IMP
-  STDMETHOD(Init)();
-  STDMETHOD_(UInt32, Filter)(Byte *data, UInt32 size);
+  INTERFACE_ICompressFilter(;)
 };
 
 class CByteSwap4:
@@ -24,8 +23,7 @@ class CByteSwap4:
 {
 public:
   MY_UNKNOWN_IMP
-  STDMETHOD(Init)();
-  STDMETHOD_(UInt32, Filter)(Byte *data, UInt32 size);
+  INTERFACE_ICompressFilter(;)
 };
 
 STDMETHODIMP CByteSwap2::Init() { return S_OK; }
@@ -33,14 +31,22 @@ 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)
+  if (size < kStep)
+    return 0;
+  size &= ~(kStep - 1);
+  
+  const Byte *end = data + (size_t)size;
+  
+  do
   {
-    Byte b = data[i];
-    data[i] = data[i + 1];
-    data[i + 1] = b;
+    Byte b0 = data[0];
+    data[0] = data[1];
+    data[1] = b0;
+    data += kStep;
   }
-  return i;
+  while (data != end);
+
+  return size;
 }
 
 STDMETHODIMP CByteSwap4::Init() { return S_OK; }
@@ -48,26 +54,34 @@ 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)
+  if (size < kStep)
+    return 0;
+  size &= ~(kStep - 1);
+  
+  const Byte *end = data + (size_t)size;
+  
+  do
   {
-    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;
+    Byte b0 = data[0];
+    Byte b1 = data[1];
+    data[0] = data[3];
+    data[1] = data[2];
+    data[2] = b1;
+    data[3] = b0;
+    data += kStep;
   }
-  return i;
+  while (data != end);
+
+  return size;
 }
 
-static void *CreateCodec2() { return (void *)(ICompressFilter *)(new CByteSwap2); }
-static void *CreateCodec4() { return (void *)(ICompressFilter *)(new CByteSwap4); }
+REGISTER_FILTER_CREATE(CreateFilter2, CByteSwap2())
+REGISTER_FILTER_CREATE(CreateFilter4, CByteSwap4())
 
-static CCodecInfo g_CodecsInfo[] =
+REGISTER_CODECS_VAR
 {
-  { CreateCodec2, CreateCodec2, 0x020302, L"Swap2", 1, true },
-  { CreateCodec4, CreateCodec4, 0x020304, L"Swap4", 1, true }
+  REGISTER_FILTER_ITEM(CreateFilter2, CreateFilter2, 0x20302, "Swap2"),
+  REGISTER_FILTER_ITEM(CreateFilter4, CreateFilter4, 0x20304, "Swap4")
 };
 
 REGISTER_CODECS(ByteSwap)