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2ff501590b
Also performed an initial run through of upgrading our Copyright date to extend to 2005 ... first run here was very simple ... change everything where: grep 1996-2004 && the word 'Copyright' ... scanned through the generated list with 'less' first, and after, to make sure that I only picked up the right entries ...
147 lines
3.7 KiB
C
147 lines
3.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* itemptr.h
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* POSTGRES disk item pointer definitions.
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*
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*
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/storage/itemptr.h,v 1.26 2004/12/31 22:03:42 pgsql Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef ITEMPTR_H
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#define ITEMPTR_H
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#include "storage/block.h"
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#include "storage/off.h"
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/*
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* ItemPointer:
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*
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* This is a pointer to an item within a disk page of a known file
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* (for example, a cross-link from an index to its parent table).
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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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* Note: because there is an item pointer in each tuple header and index
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* tuple header on disk, it's very important not to waste space with
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* structure padding bytes. The struct is designed to be six bytes long
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* (it contains three int16 fields) but a few compilers will pad it to
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* eight bytes unless coerced. We apply appropriate persuasion where
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* possible, and to cope with unpersuadable compilers, we try to use
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* "SizeOfIptrData" rather than "sizeof(ItemPointerData)" when computing
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* on-disk sizes.
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*/
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typedef struct ItemPointerData
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{
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BlockIdData ip_blkid;
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OffsetNumber ip_posid;
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}
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#ifdef __arm__
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__attribute__((packed)) /* Appropriate whack upside the head for
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* ARM */
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#endif
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ItemPointerData;
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#define SizeOfIptrData \
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(offsetof(ItemPointerData, ip_posid) + sizeof(OffsetNumber))
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typedef ItemPointerData *ItemPointer;
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/* ----------------
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* support macros
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* ----------------
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*/
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/*
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* ItemPointerIsValid
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* True iff the disk item pointer is not NULL.
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*/
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#define ItemPointerIsValid(pointer) \
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((bool) (PointerIsValid(pointer) && ((pointer)->ip_posid != 0)))
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/*
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* ItemPointerGetBlockNumber
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* Returns the block number of a disk item pointer.
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*/
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#define ItemPointerGetBlockNumber(pointer) \
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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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/*
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* ItemPointerGetOffsetNumber
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* Returns the offset number of a disk item pointer.
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*/
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#define ItemPointerGetOffsetNumber(pointer) \
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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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/*
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* ItemPointerSet
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* Sets a disk item pointer to the specified block and offset.
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*/
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#define ItemPointerSet(pointer, blockNumber, offNum) \
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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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/*
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* ItemPointerSetBlockNumber
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* Sets a disk item pointer to the specified block.
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*/
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#define ItemPointerSetBlockNumber(pointer, blockNumber) \
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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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/*
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* ItemPointerSetOffsetNumber
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* Sets a disk item pointer to the specified offset.
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*/
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#define ItemPointerSetOffsetNumber(pointer, offsetNumber) \
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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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/*
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* ItemPointerCopy
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* Copies the contents of one disk item pointer to another.
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*/
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#define ItemPointerCopy(fromPointer, toPointer) \
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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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/*
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* ItemPointerSetInvalid
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* Sets a disk item pointer to be invalid.
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*/
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#define ItemPointerSetInvalid(pointer) \
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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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/* ----------------
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* externs
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* ----------------
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*/
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extern bool ItemPointerEquals(ItemPointer pointer1, ItemPointer pointer2);
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#endif /* ITEMPTR_H */
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