private static bool equals( this ITree tree, ITree target )
{
if ( tree == null || target == null )
return false;
string treeText = tree.Text;
string targetText = target.Text;
if ( ( treeText == null ) != ( targetText == null ) )
return false;
if ( treeText == null )
return tree.Type == target.Type;
return ( treeText == targetText ) && ( tree.Type == target.Type );
}
private static IEnumerable<ITree> DoWorkForFindAll( ITree nodeToSearch, ITree target, bool partialMatch )
{
if ( ( partialMatch && nodeToSearch.equalsTreePartial( target ) )
|| ( !partialMatch && nodeToSearch.equalsTree( target ) ) )
{
yield return nodeToSearch;
}
for ( int i = 0; i < nodeToSearch.ChildCount; i++ )
{
ITree child = nodeToSearch.GetChild( i );
if ( child != null )
{
foreach ( ITree tree in DoWorkForFindAll( child, target, partialMatch ) )
yield return tree;
}
}
}
private static bool equalsTree( this ITree tree, ITree target )
{
// if either tree is nil, then they are equal only if both are nil
bool treeNil = ( ( tree == null ) || ( tree.IsNil && tree.ChildCount == 0 ) );
bool targetNil = ( ( target == null ) || ( target.IsNil && target.ChildCount == 0 ) );
if ( treeNil || targetNil )
return ( treeNil == targetNil );
if ( tree.ChildCount != target.ChildCount )
return false;
// check roots first
if ( !tree.equals( target ) )
return false;
// if roots match, do a full list match on children.
// we know tree and target have the same ChildCount.
int childCount = tree.ChildCount;
for ( int i = 0; i < childCount; i++ )
{
if ( !tree.GetChild( i ).equalsTree( target.GetChild( i ) ) )
{
return false;
}
}
return true;
}
/** Walk the tree looking for all subtrees. Return
* an enumeration that lets the caller walk the list
* of subtree roots found herein.
*/
public static IEnumerable<ITree> findAllPartial( this ITree tree, ITree node )
{
return DoWorkForFindAll( tree, node, true );
}
private static bool equalsTreePartial( this ITree tree, ITree target )
{
// an empty tree is always a subset of any tree
if ( target == null || target.IsNil )
return true;
if ( target.ChildCount > tree.ChildCount )
return false;
// check roots first
if ( !tree.equals( target ) )
return false;
// if roots match, do a full list partial test on children
int childCount = Math.Min( tree.ChildCount, target.ChildCount );
for ( int i = 0; i < childCount; i++ )
{
if ( !tree.GetChild( i ).equalsTreePartial( target.GetChild( i ) ) )
{
return false;
}
}
return true;
}
