Revert "Bug 1969820: Remove 0x00 0x0a and trailing nulls from clipboard a=dmeehan" as part of reverting Bug 1966443

This reverts commit e7e395f.

Author: DonalMe

widget/windows/nsClipboard.cpp

@@ -704,32 +704,34 @@ HRESULT nsClipboard::FillSTGMedium(IDataObject* aDataObject, UINT aFormat,
 // Get the data out of the global data handle. The size we
 // return should be the size returned from GetGlobalData(), since the
 // string returned from Windows may have nulls inserted -- it may not
-// even be null-terminated.  This does not agree with the documentation of
-// CF_TEXT/CF_UNICODETEXT but it is reality.  GetGlobalData
-// adds bytes for null termination to the buffer but they are not considered
-// in the returned byte count.  We check and skip bytes based on the policy
-// described below.  See also GetGlobalData.
+// even be null-terminated.  GetGlobalData adds bytes for null
+// termination to the buffer but they are not considered in the returned
+// byte count.  We check and skip the last counted byte if it is a null
+// since Windows also appears to add null termination.  See GetGlobalData.
 template <typename CharType>
 static nsresult GetCharDataFromGlobalData(STGMEDIUM& aStm, CharType** aData,
                                           uint32_t* aByteLen) {
   uint32_t nBytes = 0;
   MOZ_TRY(nsClipboard::GetGlobalData(aStm.hGlobal,
                                      reinterpret_cast<void**>(aData), &nBytes));
   auto nChars = nBytes / sizeof(CharType);
+  if (nChars < 1) {
+    *aByteLen = 0;
+    return NS_OK;
+  }
 
-  // Word sometimes adds a null, then a LF (0x0a), to the end of strings.
-  // Special case their removal.
-  if (nChars > 1 &&
-      (*aData)[nChars-2] == CharType(0) &&
-      (*aData)[nChars-1] == CharType(0xa)) {
+  const CharType* data = *aData;
+  if (nChars > 1 && data[nChars - 2] == CharType(0x00) &&
+      data[nChars - 1] == CharType(0x0a)) {
+    // The char array ends in the nonsense combination null + LF.  Remove both.
+    // Word sometimes does this.
     nChars -= 2;
+  } else if (data[nChars - 1] == CharType(0)) {
+    // Remove null termination.
+    nChars -= 1;
   }
-  // Remove any nulls that appear at the end of the string.
-  CharType* afterLastChar = *aData + nChars;
-  auto it = std::find_if(
-      std::reverse_iterator(afterLastChar), std::reverse_iterator(*aData),
-      [](CharType ch) { return ch != CharType(0); });
-  *aByteLen = std::distance(*aData, it.base()) * sizeof(CharType);
+  *aByteLen = nChars * sizeof(CharType);
+
   return NS_OK;
 }