From 91205e63461aa56143497795b519a39a983d3838 Mon Sep 17 00:00:00 2001
From: ganovelli <fabio.ganovelli@isti.cnr.it>
Date: Thu, 29 Apr 2004 01:00:07 +0000
Subject: [PATCH] created

---
 vcg/complex/edgemesh/allocate.h | 198 ++++++++++++++++++++++++++++++++
 1 file changed, 198 insertions(+)
 create mode 100644 vcg/complex/edgemesh/allocate.h

diff --git a/vcg/complex/edgemesh/allocate.h b/vcg/complex/edgemesh/allocate.h
new file mode 100644
index 00000000..bf16afb2
--- /dev/null
+++ b/vcg/complex/edgemesh/allocate.h
@@ -0,0 +1,198 @@
+/****************************************************************************
+* VCGLib                                                            o o     *
+* Visual and Computer Graphics Library                            o     o   *
+*                                                                _   O  _   *
+* Copyright(C) 2004                                                \/)\/    *
+* Visual Computing Lab                                            /\/|      *
+* ISTI - Italian National Research Council                           |      *
+*                                                                    \      *
+* All rights reserved.                                                      *
+*                                                                           *
+* 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 2 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 (http://www.gnu.org/licenses/gpl.txt)          *
+* for more details.                                                         *
+*                                                                           *
+****************************************************************************/
+/****************************************************************************
+  History
+
+$Log: not supported by cvs2svn $
+
+
+****************************************************************************/
+
+#ifndef __VCGLIB_EDGEALLOCATOR
+#define __VCGLIB_EDGEALLOCATOR
+
+namespace vcg {
+namespace edge {
+/** \addtogroup trimesh */
+/*@{*/
+/// Class to safely add vertexes and faces to a mesh updating all the involved pointers.
+/// It provides static memeber to add either vertex or faces to a trimesh.
+template <class AllocateMeshType>
+class Allocator
+{
+ 
+public:
+typedef AllocateMeshType MeshType; 
+typedef typename MeshType::VertexType     VertexType;
+typedef typename MeshType::VertexPointer  VertexPointer;
+typedef typename MeshType::VertexIterator VertexIterator;
+typedef typename MeshType::EdgeType       EdgeType;
+typedef typename MeshType::EdgePointer    EdgePointer;
+typedef typename MeshType::EdgeIterator   EdgeIterator;
+
+/** This class is used when allocating new vertexes and faces to update 
+   the pointers that can be changed when resizing the involved vectors of vertex or faces.
+   It can also be used to prevent any update of the various mesh fields
+   (e.g. in case you are building all the connections by hand as in a importer);
+*/ 
+template<class SimplexPointerType>
+class PointerUpdater
+{
+public:
+  void Clear(){newBase=oldBase=newEnd=oldEnd=0;preventUpdateFlag=false;};
+  void Update(SimplexPointerType &vp)
+  {
+    vp=newBase+(vp-oldBase);
+  }
+  bool NeedUpdate() {if(newBase!=oldBase && !preventUpdateFlag) return true; else return false;}
+  
+  SimplexPointerType oldBase;
+  SimplexPointerType newBase;
+  SimplexPointerType newEnd;
+  SimplexPointerType oldEnd;
+  bool preventUpdateFlag; /// when true no update is considered necessary.
+};
+
+
+/** Function to add n vertices to the mesh. The second parameter hold a vector of 
+	pointers to pointer to elements of the mesh that should be updated after a 
+	possible vector realloc. 
+	@param n Il numero di vertici che si vuole aggiungere alla mesh.
+	@param local_var Vettore di variabili locali che rappresentano puntatori a vertici. 
+	restituisce l'iteratore al primo elemento aggiunto.
+*/
+static VertexIterator AddVertices(MeshType &m,int n, PointerUpdater<VertexPointer> &pu)
+{
+  VertexIterator last=m.vert.end();
+  pu.Clear();
+	if(m.vert.empty()) pu.oldBase=0;  // if the vector is empty we cannot find the last valid element
+	else               pu.oldBase=&*m.vert.begin(); 
+    
+	for(int i=0; i<n; ++i)
+	{
+    m.vert.push_back(MeshType::VertexType());
+		m.vert.back().ClearFlags();
+	}
+
+	m.vn+=n;
+
+	pu.newBase = &*m.vert.begin();
+	if(pu.NeedUpdate())
+		{
+			EdgeIterator ei;
+			for (ei=m.edges.begin(); ei!=m.edges.end(); ++ei)
+        if(!(*ei).IsD())
+        {
+          pu.Update((*ei).V(0));
+          pu.Update((*ei).V(1));
+        }
+		
+		// e poiche' lo spazio e' cambiato si ricalcola anche last da zero  
+			unsigned int siz=m.vert.size()-n;	
+		  if(last!=0)  
+			{ 
+				last = m.vert.begin(); 
+				advance(last,siz);
+			}
+			else last=m.vert.begin(); 
+		}
+ 
+	return last;// deve restituire l'iteratore alla prima faccia aggiunta;
+}
+
+static VertexIterator AddVertices(MeshType &m, int n)
+{
+    PointerUpdater<VertexPointer> pu;
+    return AddVertices(m, n,pu);
+}
+
+/** Function to add n faces to the mesh.
+	@param n Il numero di facce che si vuole aggiungere alla mesh
+*/
+static EdgeIterator AddEdges(MeshType &m, int n)
+{
+	PointerUpdater<EdgePointer> pu;
+  return AddEdges(m,n,pu);
+}
+/** Function to add n faces to the mesh. 
+  NOTA: Aggiorna fn;
+*/
+static EdgeIterator AddEdges(MeshType &m, int n, PointerUpdater<EdgePointer> &pu)
+{
+  EdgeIterator last=0;
+  pu.Clear();
+  if(m.edges.empty()) {
+    pu.oldBase=0;  // if the vector is empty we cannot find the last valid element
+    last=0;
+  }	else  {
+    pu.oldBase=&*m.edges.begin(); 
+    last=m.edges.end();
+  } 
+	for(int i=0; i<n; ++i)
+	{
+    m.edges.push_back(MeshType::EdgeType());
+		m.edges.back().ClearFlags();
+	}
+
+	m.fn+=n;
+	
+  pu.newBase = &*m.edges.begin();
+
+  if(pu.NeedUpdate())
+		{
+      EdgeIterator ei;
+			for (ei=m.edges.begin(); ei!=m.edges.end(); ++ei)
+        if(!(*ei).IsD())
+        {
+          if(EdgeType::HasEEAdjacency())
+          {
+						pu.Update((*ei).E(0));
+            pu.Update((*ei).E(1));
+          }
+        }
+      VertexIterator ei;
+			for (ei=m.vert.begin(); ei!=m.vert.end(); ++ei)
+        if(!(*ei).IsD())
+        {
+          if(VertexType::HasVEAdjacency())
+            pu.Update((*ei).Ep());
+        }
+        		// e poiche' lo spazio e' cambiato si ricalcola anche last da zero  
+		unsigned int siz=m.edges.size()-n;	
+		if(last!=0)  
+			{ 
+				last = m.edges.begin(); 
+				advance(last,siz);
+			}
+ 		else last=m.edges.begin(); 
+		}
+
+	return last;
+}
+
+}; // end class
+/*@}*/
+} // End Namespace TriMesh
+} // End Namespace vcg
+
+#endif
\ No newline at end of file