/*-------------------------------------------------------------------------
 *
 * strat.h--
 *	  index strategy type definitions
 *	  (separated out from original istrat.h to avoid circular refs)
 *
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 * $Id: strat.h,v 1.6 1997/09/08 02:34:27 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef STRAT_H
#define STRAT_H

#include <access/skey.h>

typedef uint16 StrategyNumber;

#define InvalidStrategy 0

typedef struct StrategyTransformMapData
{
	StrategyNumber strategy[1]; /* VARIABLE LENGTH ARRAY */
}			StrategyTransformMapData;	/* VARIABLE LENGTH

										 *
										 * STRUCTURE */

typedef StrategyTransformMapData *StrategyTransformMap;

typedef struct StrategyOperatorData
{
	StrategyNumber strategy;
	bits16		flags;			/* scan qualification flags h/skey.h */
}			StrategyOperatorData;

typedef StrategyOperatorData *StrategyOperator;

typedef struct StrategyTermData
{								/* conjunctive term */
	uint16		degree;
	StrategyOperatorData operatorData[1];		/* VARIABLE LENGTH */
}			StrategyTermData;	/* VARIABLE LENGTH STRUCTURE */

typedef StrategyTermData *StrategyTerm;

typedef struct StrategyExpressionData
{								/* disjunctive normal form */
	StrategyTerm term[1];		/* VARIABLE LENGTH ARRAY */
}			StrategyExpressionData;		/* VARIABLE LENGTH STRUCTURE */

typedef StrategyExpressionData *StrategyExpression;

typedef struct StrategyEvaluationData
{
	StrategyNumber maxStrategy;
	StrategyTransformMap negateTransform;
	StrategyTransformMap commuteTransform;
	StrategyTransformMap negateCommuteTransform;
	StrategyExpression expression[12];	/* XXX VARIABLE LENGTH */
}			StrategyEvaluationData;		/* VARIABLE LENGTH STRUCTURE */

typedef StrategyEvaluationData *StrategyEvaluation;

/*
 * StrategyTransformMapIsValid --
 *		Returns true iff strategy transformation map is valid.
 */
#define StrategyTransformMapIsValid(transform) PointerIsValid(transform)


#ifndef CorrectStrategies		/* XXX this should be removable */
#define AMStrategies(foo)		12
#else							/* !defined(CorrectStrategies) */
#define AMStrategies(foo)		(foo)
#endif							/* !defined(CorrectStrategies) */

typedef struct StrategyMapData
{
	ScanKeyData entry[1];		/* VARIABLE LENGTH ARRAY */
}			StrategyMapData;	/* VARIABLE LENGTH STRUCTURE */

typedef StrategyMapData *StrategyMap;

typedef struct IndexStrategyData
{
	StrategyMapData strategyMapData[1]; /* VARIABLE LENGTH ARRAY */
}			IndexStrategyData;	/* VARIABLE LENGTH STRUCTURE */

typedef IndexStrategyData *IndexStrategy;

#endif							/* STRAT_H */