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// This class implements a tree header that can operate in one of three states, in 
// the following order:
//
// - no sort (natural order)
// - sort forwards
// - sort backwards
//
// When it reaches the end, it cycles back to the start (no sort). 

#include "CTriStateTableHeader.h"

CTriStateTableHeader::CTriStateTableHeader ( LStream* inStream )
:	LTableViewHeader(inStream)
{
}

CTriStateTableHeader :: ~CTriStateTableHeader ( )
{
}

//
// CycleSortDirection
//
// Called when the user clicks (not drags) in a column header.
//
bool
CTriStateTableHeader :: CycleSortDirection ( ColumnIndexT & ioColumn ) 
{
	if ( ioColumn == mSortedColumn ) {
		if ( mSortedBackwards ) {
			ioColumn = LArray::index_Bad;
			mSortedBackwards = true;		// so inversion below will set it to false
		}
		return !mSortedBackwards;
	}
	
	// a new column was clicked, just return current sort direction
	return mSortedBackwards;

} // CycleSortDirection