1996-08-28 03:59:28 +02:00
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/*-------------------------------------------------------------------------
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*
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1999-02-14 00:22:53 +01:00
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* itemptr.h
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1997-09-07 07:04:48 +02:00
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* POSTGRES disk item pointer definitions.
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1996-08-28 03:59:28 +02:00
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*
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*
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2001-01-24 20:43:33 +01:00
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* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
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2000-01-26 06:58:53 +01:00
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* Portions Copyright (c) 1994, Regents of the University of California
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1996-08-28 03:59:28 +02:00
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*
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2001-03-22 05:01:46 +01:00
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* $Id: itemptr.h,v 1.17 2001/03/22 04:01:06 momjian Exp $
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1996-08-28 03:59:28 +02:00
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*
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*-------------------------------------------------------------------------
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*/
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1997-09-07 07:04:48 +02:00
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#ifndef ITEMPTR_H
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1996-08-28 03:59:28 +02:00
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#define ITEMPTR_H
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1999-07-16 01:04:24 +02:00
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#include "storage/block.h"
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1999-07-16 19:07:40 +02:00
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#include "storage/off.h"
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1996-08-28 03:59:28 +02:00
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/*
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* ItemPointer:
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*
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* this is a pointer to an item on another disk page in the same file.
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* blkid tells us which block, posid tells us which entry in the linp
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* (ItemIdData) array we want.
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*/
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1997-09-07 07:04:48 +02:00
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typedef struct ItemPointerData
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{
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1997-09-08 04:41:22 +02:00
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BlockIdData ip_blkid;
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OffsetNumber ip_posid;
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1997-09-08 23:56:23 +02:00
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} ItemPointerData;
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1996-08-28 03:59:28 +02:00
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2001-03-22 05:01:46 +01:00
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#define SizeOfIptrData \
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2000-07-04 03:49:44 +02:00
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(offsetof(ItemPointerData, ip_posid) + sizeof(OffsetNumber))
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1997-09-07 07:04:48 +02:00
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typedef ItemPointerData *ItemPointer;
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1996-08-28 03:59:28 +02:00
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/* ----------------
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1997-09-07 07:04:48 +02:00
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* support macros
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1996-08-28 03:59:28 +02:00
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* ----------------
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*/
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/*
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1999-05-25 18:15:34 +02:00
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* ItemPointerIsValid
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1997-09-07 07:04:48 +02:00
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* True iff the disk item pointer is not NULL.
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1996-08-28 03:59:28 +02:00
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*/
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#define ItemPointerIsValid(pointer) \
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1997-09-07 07:04:48 +02:00
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((bool) (PointerIsValid(pointer) && ((pointer)->ip_posid != 0)))
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1996-08-28 03:59:28 +02:00
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/*
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1999-05-25 18:15:34 +02:00
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* ItemPointerGetBlockNumber
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1997-09-07 07:04:48 +02:00
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* Returns the block number of a disk item pointer.
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1996-08-28 03:59:28 +02:00
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*/
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#define ItemPointerGetBlockNumber(pointer) \
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1998-06-15 20:40:05 +02:00
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( \
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AssertMacro(ItemPointerIsValid(pointer)), \
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BlockIdGetBlockNumber(&(pointer)->ip_blkid) \
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)
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1996-08-28 03:59:28 +02:00
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/*
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1999-05-25 18:15:34 +02:00
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* ItemPointerGetOffsetNumber
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1997-09-07 07:04:48 +02:00
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* Returns the offset number of a disk item pointer.
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1996-08-28 03:59:28 +02:00
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*/
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#define ItemPointerGetOffsetNumber(pointer) \
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1998-06-15 20:40:05 +02:00
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( \
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AssertMacro(ItemPointerIsValid(pointer)), \
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(pointer)->ip_posid \
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)
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1996-08-28 03:59:28 +02:00
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/*
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1999-05-25 18:15:34 +02:00
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* ItemPointerSet
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1997-09-07 07:04:48 +02:00
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* Sets a disk item pointer to the specified block and offset.
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1996-08-28 03:59:28 +02:00
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*/
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#define ItemPointerSet(pointer, blockNumber, offNum) \
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1998-06-15 20:40:05 +02:00
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( \
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AssertMacro(PointerIsValid(pointer)), \
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BlockIdSet(&((pointer)->ip_blkid), blockNumber), \
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(pointer)->ip_posid = offNum \
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)
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1996-08-28 03:59:28 +02:00
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/*
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1999-05-25 18:15:34 +02:00
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* ItemPointerSetBlockNumber
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1997-09-07 07:04:48 +02:00
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* Sets a disk item pointer to the specified block.
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1996-08-28 03:59:28 +02:00
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*/
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#define ItemPointerSetBlockNumber(pointer, blockNumber) \
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1998-06-15 20:40:05 +02:00
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( \
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AssertMacro(PointerIsValid(pointer)), \
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BlockIdSet(&((pointer)->ip_blkid), blockNumber) \
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)
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1996-08-28 03:59:28 +02:00
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/*
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1999-05-25 18:15:34 +02:00
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* ItemPointerSetOffsetNumber
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1997-09-07 07:04:48 +02:00
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* Sets a disk item pointer to the specified offset.
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1996-08-28 03:59:28 +02:00
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*/
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#define ItemPointerSetOffsetNumber(pointer, offsetNumber) \
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1998-06-15 20:40:05 +02:00
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( \
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AssertMacro(PointerIsValid(pointer)), \
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(pointer)->ip_posid = (offsetNumber) \
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)
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1996-08-28 03:59:28 +02:00
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/*
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1999-05-25 18:15:34 +02:00
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* ItemPointerCopy
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1997-09-07 07:04:48 +02:00
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* Copies the contents of one disk item pointer to another.
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1996-08-28 03:59:28 +02:00
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*/
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#define ItemPointerCopy(fromPointer, toPointer) \
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1998-06-15 20:40:05 +02:00
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( \
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AssertMacro(PointerIsValid(toPointer)), \
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AssertMacro(PointerIsValid(fromPointer)), \
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*(toPointer) = *(fromPointer) \
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)
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1996-08-28 03:59:28 +02:00
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/*
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1999-05-25 18:15:34 +02:00
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* ItemPointerSetInvalid
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1997-09-07 07:04:48 +02:00
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* Sets a disk item pointer to be invalid.
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1996-08-28 03:59:28 +02:00
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*/
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#define ItemPointerSetInvalid(pointer) \
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1998-06-15 20:40:05 +02:00
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( \
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AssertMacro(PointerIsValid(pointer)), \
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BlockIdSet(&((pointer)->ip_blkid), InvalidBlockNumber), \
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(pointer)->ip_posid = InvalidOffsetNumber \
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)
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1996-08-28 03:59:28 +02:00
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/* ----------------
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1997-09-07 07:04:48 +02:00
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* externs
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1996-08-28 03:59:28 +02:00
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* ----------------
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*/
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1997-09-08 04:41:22 +02:00
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extern bool ItemPointerEquals(ItemPointer pointer1, ItemPointer pointer2);
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1996-08-28 03:59:28 +02:00
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1998-09-01 06:40:42 +02:00
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#endif /* ITEMPTR_H */
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