C++ CAtlList::InsertBefore方法代码示例

//THIS FUNCTION IS QUITE COMPLICATED BECAUSE 
//IT HAS TO DEAL WITH MAYA NAME MANGLING!
//tokenize the path.
//add each token into the element list which tracks the attributes and indices
//for each entry added make sure there are no parents left out from maya name mangling.
//after the list is populated and missing elements area added 
//we reiterate and produce the final result.
MPlug		FxInternal::DecodePlug(const CStringA& plugStr)
{

	MPlug result;
	MFnDependencyNode depNode(GetSite());

	CAtlList<PathDecodeElement> elementList;

	//tokenize the path
	int iLastPos=0;
	int iThisPos=0;
	CStringA subStr;
	while( iLastPos= iThisPos, 
		subStr=plugStr.Tokenize(".[]", iThisPos), 
		iThisPos != -1 )
	{
		//char lastChar= subStr[iLastPos];
		//char thisChar= subStr[iThisPos];

		//are we looking at a named portion?
		if(iLastPos == 0 
			|| plugStr[iLastPos-1]=='.'
			|| (plugStr[iLastPos-1]==']' && plugStr[iLastPos]=='.'))
		{
			//if the name is length zero then it must be the case when 
			// you do last[#].  The situation is caused by  the sequence "]."
			//if we dont have a name we can skip since only 1d arrays are allowed.

			if(subStr.GetLength() > 0)
			{
		
				//everything we add is going to be based on the current tail.
				//because we are adding parents, as we find parents we can continue
				//to add them to this position so that they will order themselves properly
				POSITION insertPos= elementList.GetTailPosition();

				//calculate the cancel condition.
				//it is the current tail's object if a tail exists otherwise NULL
				//NULL indicates go all the way to the root
				MObject cancelObj= MObject::kNullObj;
				if(elementList.GetCount() > 0)
				{
					cancelObj= elementList.GetTail().Attribute.object();
				}


				//get the object we are currently working with
				MObject thisObj= depNode.attribute(subStr.GetString());
				if(thisObj.isNull())
					return MPlug();//Critical element of the path was not found...return NULL


				//add it to the list so that we have something to insertBefore
				elementList.AddTail();
				elementList.GetTail().Name= subStr;
				elementList.GetTail().Attribute.setObject(thisObj);



				//walk through all of the parents until we reach cancel condition.
				//we can add  the current element onto the list in the same way.
				for( MFnAttribute itrAttr( elementList.GetTail().Attribute.parent() );
					!itrAttr.object().isNull()  && (cancelObj != itrAttr.object());
					itrAttr.setObject(itrAttr.parent()))
				{
					PathDecodeElement element;
					element.Attribute.setObject( itrAttr.object() );

					//we change the position so that the grandparent is inserted before the parent
					insertPos= elementList.InsertBefore( insertPos, element);
				}
			}
		}
		//are we looking at a numbered portion?
		else if(plugStr[iLastPos-1]=='[' && plugStr[iThisPos-1]==']')
		{
			//if so change the array index.
			elementList.GetTail().IsArray= true;
			elementList.GetTail().Index = atoi( subStr.GetString() );
		}
		else
			DXCC_ASSERT(false);//VERY POORLY FORMED STRING

	}

	//produce the result plug off of the elementList.
	bool first= true;
	for(POSITION pos= elementList.GetHeadPosition();
		pos != NULL;
		elementList.GetNext(pos))
	{
		PathDecodeElement& element= elementList.GetAt(pos);

//.........这里部分代码省略.........

   // Define the integer list
   CAtlList<int> myList;

   // Populate the list
   POSITION myPos = myList.AddHead(1);
   myPos = myList.InsertBefore(myPos, 2);
   myPos = myList.InsertBefore(myPos, 3);

   // Confirm the head value is as expected
   ATLASSERT(myList.GetHead() == 3);