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engines/saga2/imagcach.cpp

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * aint32 with this program; if not, write to the Free Software
+ *
+ *
+ * Based on the original sources
+ *   Faery Tale II -- The Halls of the Dead
+ *   (c) 1993-1996 The Wyrmkeep Entertainment Co.
+ */
+
+#include "saga2/saga2.h"
+#include "saga2/fta.h"
+#include "saga2/imagcach.h"
+#include "saga2/hresmgr.h"
+
+namespace Saga2 {
+
+CImageNode::CImageNode(hResContext *con, uint32 resID) {
+	if (con) {
+		_image           = LoadResource(con, resID, "CImageNode Allocation");
+		_resourceID      = resID;
+		_contextID       = con->getResID();
+		_requested       = 0;    // zero request for this node at creation
+	} else {
+		_image = nullptr;
+		_resourceID = 0;
+		_contextID = 0;
+		_requested = 0;
+	}
+}
+
+CImageNode::~CImageNode() {
+	if (_image) {
+		free(_image);
+		_image = nullptr;
+	}
+}
+
+// figures out if the requested image is the same as this one
+bool CImageNode::isSameImage(hResContext *con, uint32 resID) {
+	if (con) {
+		if (con->getResID() == _contextID &&
+		        _resourceID == resID) {
+			return true;    // match
+		}
+	}
+
+	return false;   // no match
+}
+
+bool CImageNode::isSameImage(void *imagePtr) {
+	// if the image passed has the same address as the image in the node...
+	if (imagePtr == _image) {
+		return true;
+	}
+
+	return false;
+}
+
+// return true if this node needs to be deleted
+bool CImageNode::releaseRequest() {
+	// the number of requests on this resource goes down by one
+	_requested--;
+
+	// if that was the last request, release this node
+	if (_requested <= 0) {
+		return true;
+	}
+
+	// not the last request, keep image
+	return false;
+}
+
+void *CImageNode::getImagePtr() {
+	_requested++;
+	return _image;
+}
+
+/* ===================================================================== *
+   ImageCache member functions
+ * ===================================================================== */
+
+CImageCache::~CImageCache() {
+
+	/* >>> See notes below
+	    // return if list is empty
+	if( nodes.empty() ) return;
+
+
+	CImageNode *imageNode, *nextImageNode;
+
+
+	    // for some reason, doing a nodes.last() ( or nodes.first() )
+	    // here causes an access violation.  This might be caused
+	    // by list corruption occurring during runtime,
+	    // I'm going to disable destructor for now to run some tests
+	    // to determine cause.  This should not adversely affect normal runtime
+	    // execution as all nodes should be released DURING runtime.
+	for( imageNode = ( CImageNode * )nodes.last();
+	     imageNode != NULL;
+	     imageNode = nextImageNode )
+	{
+
+	        // keep a copy of the pointer
+	    nextImageNode = ( CImageNode *)imageNode->prev();
+
+	        // remove and delete it
+	    imageNode->remove();
+	    delete imageNode;
+
+	}
+	*/
+}
+
+void CImageCache::releaseImage(void *imagePtr) {
+	if (!imagePtr)  return;
+
+	CImageNode *imageNode;
+	Common::List<CImageNode *>::iterator nextIt;
+
+	for (Common::List<CImageNode *>::iterator it = _nodes.begin(); it != _nodes.end(); it = nextIt) {
+		nextIt = it;
+		nextIt++;
+
+		imageNode = *it;
+		if (imageNode->isSameImage(imagePtr)) {
+			// if that was the last request for the imageNode, delete it
+			if (imageNode->releaseRequest()) {
+				// remove and delete it
+				_nodes.remove(imageNode);
+				delete imageNode;
+			}
+		}
+	}
+}
+
+void *CImageCache::requestImage(hResContext *con, uint32 resID) {
+	CImageNode *imageNode;
+
+	// look through all nodes to see if we have that image already
+	for (Common::List<CImageNode *>::iterator it = _nodes.begin(); it != _nodes.end(); it++) {
+		imageNode = *it;
+
+		if (imageNode->isSameImage(con, resID)) {
+			// return the image Ptr to the already allocated image resource
+			return imageNode->getImagePtr();
+		}
+	}
+
+	// if no previously allocated image node then make one and return the
+	// ptr to the new image resource
+	// creates node and loads in the resource
+	imageNode = new CImageNode(con, resID);
+
+	// add this node to the list
+	_nodes.push_back(imageNode);
+
+	// return the newly loaded image
+	return imageNode->getImagePtr();
+}
+
+} // end of namespace Saga2