1 files changed, 133 insertions, 0 deletions
diff --git a/src/base/abc/abcRefs.c b/src/base/abc/abcRefs.c
new file mode 100644
index 00000000..b6a7dce1
--- /dev/null
+++ b/src/base/abc/abcRefs.c
@@ -0,0 +1,133 @@
+/**CFile****************************************************************
+
+  FileName    [abcRefs.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [Network and node package.]
+
+  Synopsis    [Reference counting of the nodes.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 20, 2005.]
+
+  Revision    [$Id: abcRefs.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
+
+***********************************************************************/
+
+#include "abc.h"
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+static int Abc_NodeRefDeref( Abc_Obj_t * pNode, bool fFanouts, bool fReference );
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFITIONS                           ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Procedure returns the size of the MFFC of the node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NodeMffcSize( Abc_Obj_t * pNode )
+{
+    int nConeSize1, nConeSize2;
+    assert( !Abc_ObjIsComplement( pNode ) );
+    assert( Abc_ObjIsNode( pNode ) );
+    nConeSize1 = Abc_NodeRefDeref( pNode, 0, 0 ); // dereference
+    nConeSize2 = Abc_NodeRefDeref( pNode, 0, 1 ); // reference
+    assert( nConeSize1 == nConeSize2 );
+    assert( nConeSize1 > 0 );
+    return nConeSize1;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Procedure returns the size of the MFFC of the node.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NodeMffcRemove( Abc_Obj_t * pNode )
+{
+    assert( !Abc_ObjIsComplement( pNode ) );
+    assert( Abc_ObjIsNode( pNode ) );
+    return Abc_NodeRefDeref( pNode, 1, 0 ); // dereference
+}
+
+/**Function*************************************************************
+
+  Synopsis    [References/references the node and returns MFFC size.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Abc_NodeRefDeref( Abc_Obj_t * pNode, bool fFanouts, bool fReference )
+{
+    Abc_Obj_t * pNode0, * pNode1;
+    int Counter;
+    if ( Abc_ObjIsPi(pNode) || Abc_ObjIsLatch(pNode) )
+        return 0;
+    pNode0 = Abc_ObjFanin( pNode, 0 );
+    pNode1 = Abc_ObjFanin( pNode, 1 );
+    Counter = 1;
+    if ( fReference )
+    {
+        if ( pNode0->vFanouts.nSize++ == 0 )
+        {
+            Counter += Abc_NodeRefDeref( pNode0, fFanouts, fReference );
+            if ( fFanouts )  
+                Abc_ObjAddFanin( pNode, pNode0 );
+        }
+        if ( pNode1->vFanouts.nSize++ == 0 )
+        {
+            Counter += Abc_NodeRefDeref( pNode1, fFanouts, fReference );
+            if ( fFanouts )  
+                Abc_ObjAddFanin( pNode, pNode1 );
+        }
+    }
+    else
+    {
+        assert( pNode0->vFanouts.nSize > 0 );
+        assert( pNode1->vFanouts.nSize > 0 );
+        if ( --pNode0->vFanouts.nSize == 0 )
+        {
+            Counter += Abc_NodeRefDeref( pNode0, fFanouts, fReference );
+            if ( fFanouts )  
+                Abc_ObjDeleteFanin( pNode, pNode0 );
+        }
+        if ( --pNode1->vFanouts.nSize == 0 )
+        {
+            Counter += Abc_NodeRefDeref( pNode1, fFanouts, fReference );
+            if ( fFanouts )  
+                Abc_ObjDeleteFanin( pNode, pNode1 );
+        }
+    }
+    return Counter;
+}
+
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+