xid.c

关系型数据库 Postgresql 6.5.2

/*-------------------------------------------------------------------------
 *
 * xid.c
 *	  POSTGRES transaction identifier code.
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *	$Id: xid.c,v 1.22.2.2 1999/08/02 05:56:49 scrappy Exp $
 *
 * OLD COMMENTS
 * XXX WARNING
 *		Much of this file will change when we change our representation
 *		of transaction ids -cim 3/23/90
 *
 * It is time to make the switch from 5 byte to 4 byte transaction ids
 * This file was totally reworked. -mer 5/22/92
 *
 *-------------------------------------------------------------------------
 */


#include "postgres.h"
#include "access/xact.h"

extern TransactionId NullTransactionId;
extern TransactionId DisabledTransactionId;
extern TransactionId AmiTransactionId;
extern TransactionId FirstTransactionId;

/* XXX name for catalogs */
TransactionId
xidin(char *representation)
{
	return atol(representation);
}

/* XXX name for catalogs */
char *
xidout(TransactionId transactionId)
{
	/* maximum 32 bit unsigned integer representation takes 10 chars */
	char	   *representation = palloc(11);

	snprintf(representation, 11, "%u", transactionId);

	return representation;

}

/* ----------------------------------------------------------------
 *		xideq
 * ----------------------------------------------------------------
 */

/*
 *		xideq			- returns 1, iff xid1 == xid2
 *								  0  else;
 */
bool
xideq(TransactionId xid1, TransactionId xid2)
{
	return (bool) (xid1 == xid2);
}



/* ----------------------------------------------------------------
 *		TransactionIdAdd
 * ----------------------------------------------------------------
 */
void
TransactionIdAdd(TransactionId *xid, int value)
{
	*xid += value;
	return;
}