/*
 * brin_internal.h
 *		internal declarations for BRIN indexes
 *
 * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *		src/include/access/brin_internal.h
 */
#ifndef BRIN_INTERNAL_H
#define BRIN_INTERNAL_H

#include "fmgr.h"
#include "storage/buf.h"
#include "storage/bufpage.h"
#include "storage/off.h"
#include "utils/relcache.h"


/*
 * A BrinDesc is a struct designed to enable decoding a BRIN tuple from the
 * on-disk format to an in-memory tuple and vice-versa.
 */

/* struct returned by "OpcInfo" amproc */
typedef struct BrinOpcInfo
{
	/* Number of columns stored in an index column of this opclass */
	uint16		oi_nstored;

	/* Opaque pointer for the opclass' private use */
	void	   *oi_opaque;

	/* Type IDs of the stored columns */
	Oid			oi_typids[FLEXIBLE_ARRAY_MEMBER];
} BrinOpcInfo;

/* the size of a BrinOpcInfo for the given number of columns */
#define SizeofBrinOpcInfo(ncols) \
	(offsetof(BrinOpcInfo, oi_typids) + sizeof(Oid) * ncols)

typedef struct BrinDesc
{
	/* Containing memory context */
	MemoryContext bd_context;

	/* the index relation itself */
	Relation	bd_index;

	/* tuple descriptor of the index relation */
	TupleDesc	bd_tupdesc;

	/* cached copy for on-disk tuples; generated at first use */
	TupleDesc	bd_disktdesc;

	/* total number of Datum entries that are stored on-disk for all columns */
	int			bd_totalstored;

	/* per-column info; bd_tupdesc->natts entries long */
	BrinOpcInfo *bd_info[FLEXIBLE_ARRAY_MEMBER];
} BrinDesc;

/*
 * Globally-known function support numbers for BRIN indexes.  Individual
 * opclasses define their own function support numbers, which must not collide
 * with the definitions here.
 */
#define BRIN_PROCNUM_OPCINFO		1
#define BRIN_PROCNUM_ADDVALUE		2
#define BRIN_PROCNUM_CONSISTENT		3
#define BRIN_PROCNUM_UNION			4
/* procedure numbers up to 10 are reserved for BRIN future expansion */

#define BRIN_DEBUG

/* we allow debug if using GCC; otherwise don't bother */
#if defined(BRIN_DEBUG) && defined(__GNUC__)
#define BRIN_elog(level, ...)		elog(level, __VA_ARGS__)
#else
#define BRIN_elog(a)	void(0)
#endif

/* brin.c */
extern BrinDesc *brin_build_desc(Relation rel);
extern void brin_free_desc(BrinDesc *bdesc);

#endif   /* BRIN_INTERNAL_H */