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/*-------------------------------------------------------------------------
*
* htup.h--
* POSTGRES heap tuple definitions.
*
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: htup.h,v 1.1.1.1 1996/07/09 06:21:08 scrappy Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef HTUP_H
#define HTUP_H
#include "access/attnum.h"
#include "storage/bufpage.h" /* just to reduce levels of #include */
#include "storage/itemptr.h"
#include "utils/nabstime.h"
#define MinHeapTupleBitmapSize 32 /* 8 * 4 */
/* check these, they are likely to be more severely limited by t_hoff */
#define MaxHeapAttributeNumber 1600 /* 8 * 200 */
/*
* to avoid wasting space, the attributes should be layed out in such a
* way to reduce structure padding.
*/
typedef struct HeapTupleData {
unsigned int t_len; /* length of entire tuple */
ItemPointerData t_ctid; /* current TID of this tuple */
ItemPointerData t_chain; /* replaced tuple TID */
Oid t_oid; /* OID of this tuple -- 4 bytes */
CommandId t_cmin; /* insert CID stamp -- 2 bytes each */
CommandId t_cmax; /* delete CommandId stamp */
TransactionId t_xmin; /* insert XID stamp -- 4 bytes each */
TransactionId t_xmax; /* delete XID stamp */
AbsoluteTime t_tmin; /* time stamps -- 4 bytes each */
AbsoluteTime t_tmax;
int16 t_natts; /* number of attributes */
char t_vtype; /* not used - padding */
char t_infomask; /* whether tuple as null or variable
* length attributes
*/
uint8 t_hoff; /* sizeof tuple header */
bits8 t_bits[MinHeapTupleBitmapSize / 8];
/* bit map of domains */
/* MORE DATA FOLLOWS AT END OF STRUCT */
} HeapTupleData;
typedef HeapTupleData *HeapTuple;
#define SelfItemPointerAttributeNumber (-1)
#define ObjectIdAttributeNumber (-2)
#define MinTransactionIdAttributeNumber (-3)
#define MinCommandIdAttributeNumber (-4)
#define MaxTransactionIdAttributeNumber (-5)
#define MaxCommandIdAttributeNumber (-6)
#define ChainItemPointerAttributeNumber (-7)
#define AnchorItemPointerAttributeNumber (-8)
#define MinAbsoluteTimeAttributeNumber (-9)
#define MaxAbsoluteTimeAttributeNumber (-10)
#define VersionTypeAttributeNumber (-11)
#define FirstLowInvalidHeapAttributeNumber (-12)
/* ----------------
* support macros
* ----------------
*/
#define GETSTRUCT(TUP) (((char *)(TUP)) + ((HeapTuple)(TUP))->t_hoff)
/*
* BITMAPLEN(NATTS) -
* Computes minimum size of bitmap given number of domains.
*/
#define BITMAPLEN(NATTS) \
((((((int)(NATTS) - 1) >> 3) + 4 - (MinHeapTupleBitmapSize >> 3)) \
& ~03) + (MinHeapTupleBitmapSize >> 3))
/*
* HeapTupleIsValid
* True iff the heap tuple is valid.
*/
#define HeapTupleIsValid(tuple) PointerIsValid(tuple)
/*
* information stored in t_infomask:
*/
#define HEAP_HASNULL 0x01 /* has null attribute(s) */
#define HEAP_HASVARLENA 0x02 /* has variable length attribute(s) */
#define HeapTupleNoNulls(tuple) \
(!(((HeapTuple) (tuple))->t_infomask & HEAP_HASNULL))
#define HeapTupleAllFixed(tuple) \
(!(((HeapTuple) (tuple))->t_infomask & HEAP_HASVARLENA))
#endif /* HTUP_H */
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