2.11BSD/ingres/source/parser/rngfcn.c

# include	"../ingres.h"
# include	"../aux.h"
# include	"../pipes.h"
# include	"../tree.h"
# include	"../symbol.h"
# include	"parser.h"

/*
**  RNGINIT
**	initializes the pointers in the range table
**	it should be called prior to starting the parsing
**	it also initializes the attrib stash stuff because
**	the attrib stash is really part of the range table
*/
rnginit()
{
	register int		i;
	register struct atstash	*atptr;
	register struct rngtab	*rptr;

	rptr = Rngtab;				/* ptr to head of range table */
	for (i = 0; i <= MAXVAR; i++, rptr++)	/* ">=" includes the internal entry */
	{
		rptr->ractiv = 0;
		rptr->rmark = 0;
		rptr->rposit = i;
		smove("", rptr->varname);
		smove("", rptr->relnm);
		rptr->rstat = 0;
		rptr->ratts = 0;
		rptr->attlist = NULL;
	}
	rngreset();
	atptr = Attable;
	for (i = 0; i < MAXATT - 1; i++)
	{
		atptr->atbnext = atptr + 1;
		atptr++;
	}
	atptr->atbnext = NULL;
	Freeatt = Attable;
}

/*
** RNGLOOK
**	returns a pointer to the range table entry else 0
**	type = LOOKREL	lookup relation
**	type = LOOKVAR	lookup variable
*/
struct rngtab *
rnglook(p, type)
char	*p;
int	type;
{
	register struct rngtab	*rptr;
	register char		*param;
	register int		i;

	param = p;
	rptr = Rngtab;
	switch (type)
	{
	  case LOOKVAR:
	  case LOOKREL:
		break;

	  default:
		syserr("rnglook: type '$d'", type);
	}
	for (i = 0; i < MAXVAR; i++, rptr++)	/* search external vbles only */
	{
		if (rptr->ractiv == 1 && scompare(param, MAXNAME, (type == LOOKVAR ? rptr->varname : rptr->relnm), MAXNAME) == 0)
		{
			rptr->rmark = 1;
#			ifdef	xPTR2
			tTfp(21, 6, "fnd '%s' at '%d'\n", param, rptr->rentno);
#			endif
			rngfront(rptr);
			return (rptr);
		}
	}
	return (NULL);
}

/*
** RNGENT
**	Insert variable and relation in range table.
*/
struct rngtab *
rngent(type, var, rel, relown, atts, relstat)
int	type;
char	*var;
char	*rel;
char	*relown;
int	atts;
int	relstat;
{
	register struct rngtab	*rptr;
	struct rngtab		*rngatndx();

#	ifdef	xPTR2
	if (tTf(21, 0))
	{
		printf("rngent:\ttyp=%d\tvar=%s\trel=%s\n\town=%.2s\tatts=%d\tstat=%o\n", type, var, rel, relown, atts, relstat);
	}
#	endif
	if (type == R_INTERNAL)
		rptr = &Rngtab[MAXVAR];
	else if (type == R_EXTERNAL)
	{
		if ((rptr = rnglook(var, LOOKVAR)) == NULL)
		{
			/* not in range table */
			rptr = rngatndx(MAXVAR - 1);
		}
		rngfront(rptr);
	}
	else
		syserr("rngent: type '%d'", type);
	if (scompare(rel, MAXNAME, rptr->relnm, MAXNAME) != 0 ||
		!bequal(relown, rptr->relnowner, 2))
	{
		attfree(rptr->attlist);
		rptr->attlist = NULL;
	}

	pmove(var, rptr->varname, MAXNAME, '\0');
	pmove(rel, rptr->relnm, MAXNAME, '\0');
	bmove(relown, rptr->relnowner, 2);
	rptr->ractiv = 1;
	rptr->ratts = atts;
	rptr->rstat = relstat;
	return (rptr);
}

/*
** RNGDEL
**	removes an entry from the range table
**	removes all variables for the relation name
*/
rngdel(rel)
char	*rel;
{
	register struct rngtab	*rptr;

	while ((rptr = rnglook(rel, LOOKREL)) != NULL)
	{
		smove("", rptr->relnm);
		smove("", rptr->varname);
		rptr->rmark = 0;
		rptr->ractiv = 0;
		rngback(rptr);
		attfree(rptr->attlist);
		rptr->attlist = NULL;
	}
}

/*
** RNGSEND
**	Writes range table information needed by DECOMP and OVQP.
*/
rngsend()
{
	register struct rngtab	*rptr;
	register int		i;

	rptr = Rngtab;
	for (i = 0; i < MAXVAR; i++, rptr++)
	{
		if (rptr->rmark != 0)
		{
			rngwrite(rptr);
		}
	}

	/* send result relation range entry if not already sent */
	if (Resrng && Resrng->rentno == MAXVAR)
	{
		rngwrite(Resrng);
	}
}

/*
** RNGFRONT
**	move entry 'r' to head of range table list
*/
rngfront(r)
struct rngtab	*r;
{
	register struct rngtab	*rptr;
	register struct rngtab	*fptr;
	register int		i;

	fptr = r;
	rptr = Rngtab;
	for (i = 0; i < MAXVAR; i++, rptr++)	/* check all external vbles */
	{
		if (rptr->rposit < fptr->rposit)
			rptr->rposit++;
	}
	fptr->rposit = 0;
}

/*
** RNGBACK
**	move entry 'r' to back of range table list
*/
rngback(r)
struct rngtab	*r;
{
	register struct rngtab	*rptr;
	register struct rngtab	*bptr;
	register int		i;

	bptr = r;
	rptr = Rngtab;
	for (i = 0; i < MAXVAR; i++, rptr++)	/* check all external vbles */
	{
		if (rptr->rposit > bptr->rposit)
			rptr->rposit--;
	}
	bptr->rposit = MAXVAR - 1;
}

/*
** RNGRESET
**	reset the used marks to '0'
*/
rngreset()
{
	register struct rngtab	*rptr;
	register int		i;

	rptr = Rngtab;
	for (i = MAXVAR - 1; i >= 0; i--, rptr++)	/* only do external ones */
	{
		rptr->rmark = 0;
		rptr->rentno = i;
	}
	Rngtab[MAXVAR].rentno = MAXVAR;		/* internal vble is always MAXVAR */
}

/*
**  RNGOLD -- find least recently used vble entry
*/
struct rngtab *
rngatndx(ndx)
int	ndx;
{
	register struct rngtab	*rptr;
	register int		i;

	rptr = Rngtab;
	for (i = 0; i < MAXVAR; i++, rptr++)	/* do external vbles */
	{
		if (rptr->rposit == ndx)
			return (rptr);
	}
	syserr("rngatndx: can't find %d", ndx);
}

/*
** CHECKUPD
**	checks to make sure that the user can update the relation 'name1'
**	the 'open' parameter is set if 'Reldesc' contains the openr info
**	for the relation in question.
*/
checkupd(rptr)
struct rngtab	*rptr;
{
	if (!Noupdt)
		return;
	if (rptr->rstat & S_NOUPDT)
		/* no updates allowed on this relation */
		yyerror(CANTUPDATE, rptr->relnm, 0);
}

/*
** RNGFRESH -- check the range table relstat information for accuracy
**
**	If the command specified could have changed the relstat info
**	make the appropriate adjustments to the range table
*/
rngfresh(op)
int	op;
{
	register struct rngtab	*rptr;
	register int		i;
	struct descriptor	desc;

	/* search the entire table! */
	for (i = 0, rptr = Rngtab; i <= MAXVAR; i++, rptr++)
	{
		if (!rptr->ractiv)
			continue;
		switch (op)
		{
		  case mdDESTROY:
			if ((rptr->rstat & (S_VBASE | S_INTEG | S_PROTUPS | S_INDEX)) != 0)
			{
			fixordel:
				/*
				** openr the relation, if it doesn't exist make
				** sure that all range table entries are gone
				*/
				if (!openr(&desc, -1, rptr->relnm))
				{
					/* relation still there, copy bits anyway */
					rptr->rstat = desc.relstat;
				}
				else
				{
					/* relation not there, purge table */
					rngdel(rptr->relnm);
				}
			}
			break;

		  case mdVIEW:
			if ((rptr->rstat & S_VBASE) == 0)
			{
			fixorerr:
				/*
				** if the relation doesn't exist then it is
				** a syserr, otherwise, copy the bits.
				*/
				if (!openr(&desc, -1, rptr->relnm))
				{
					/* exists, copy bits */
					rptr->rstat = desc.relstat;
				}
				else
				{
					/* not there, syserr */
					syserr("RNGFRESH: extra entry: %s", rptr->relnm);
				}
			}
			break;

		  case mdPROT:
			if ((rptr->rstat & S_PROTUPS) == 0)
				goto	fixorerr;
			break;

		  case mdINTEG:
			if ((rptr->rstat & S_INTEG) == 0)
				goto	fixorerr;
			break;

		  case mdMODIFY:
			if ((rptr->rstat & S_INDEX) != 0)
				goto	fixordel;
			break;
		
		  default:
			return;	/* command ok, dont waste time on rest of table */
		}
	}
}