ING_DB

WEGA/contrib/ingres/dbs/src/decomp/rnum.c

@@ -0,0 +1,178 @@
+# include	<stdio.h>
+# include	"gen.h"
+# include	"../h/dbs.h"
+# include	"../h/aux.h"
+# include	"../h/tree.h"
+# include	"../h/pipes.h"
+# include	"decomp.h"
+
+# define	FIRSTNUM	MAXRANGE + 3
+# define	LASTNUM		100
+
+/*
+**	Internal numbers are used in decomp to
+**	represent relation names. The numbers
+**	from 0 to FIRSTNUM-1 refer to the names
+**	stored in Name_table[].
+**
+**	The number from FIRSTNUM to LASTNUM have
+**	names which are computed from aa, ab, etc.
+*/
+static char	Name_table[FIRSTNUM - 1][MAXNAME];
+static char	Num_used[LASTNUM + 1];
+char		SYSNAME[]	= "_SYS";
+int		s_SYSNAME	= sizeof SYSNAME - 1;
+
+
+rnum_assign(name)
+char	*name;
+
+/*
+**	Assign an internal number rnum to name.
+*/
+
+{
+	register int	i;
+
+	for (i = 0; i < FIRSTNUM; i++)
+		if (Num_used[i] == 0)
+		{
+			AAbmove(name, Name_table[i], MAXNAME);
+			Num_used[i]++;
+			return (i);
+		}
+	AAsyserr(12022);
+}
+
+rnum_alloc()
+
+/*
+**	Allocate the next available name
+*/
+
+{
+	register int	i;
+	register char	*cp;
+
+	cp = &Num_used[FIRSTNUM];
+	for (i = FIRSTNUM; i < LASTNUM; i++)
+		if (*cp++ == 0)
+		{
+			--cp;
+			(*cp)++;
+			return (i);
+		}
+	AAsyserr(12023);
+}
+
+
+/*
+**	Convert internal relation number
+**	to its real name. Guarantee '\0' at end.
+*/
+
+# ifdef EBCDIC
+static char	Rnum[] = "abcdefghijklmnopqrstuvwxyz";
+# endif
+
+char	*rnum_convert(num)
+int	num;
+{
+	register int	i;
+	register char	*ret;
+	register char	*cp;
+	static char	temp[MAXNAME+1];
+	extern char	*Fileset;
+	extern char	*AAconcat();
+
+	i = num;
+	if (i > LASTNUM || Num_used[i] == 0)
+		AAsyserr(12024, i);
+
+	ret = temp;
+
+	if (i < FIRSTNUM)
+		AAbmove(Name_table[i], ret, MAXNAME);
+	else
+	{
+		/* compute temp name */
+		cp = AAconcat(SYSNAME, Fileset, ret);
+		AApad(ret, MAXNAME);
+		i -= FIRSTNUM;
+# ifdef EBCDIC
+		*cp++ = Rnum[i / 26];
+		*cp = Rnum[i % 26];
+# else
+		*cp++ = i / 26 + 'a';
+		*cp = i % 26 + 'a';
+# endif
+	}
+	return (ret);
+}
+
+rnum_remove(num)
+int	num;
+
+/*
+**	Remove a num from the used list
+*/
+
+{
+	register char	*cp;
+
+	cp = &Num_used[num];
+
+	if (*cp == 0)
+		AAsyserr(12025, num);
+	*cp = 0;
+}
+
+
+rnum_last()
+
+/*
+**	returns number of largest assigned temp number.
+**	zero if none
+*/
+
+{
+	register int	i;
+
+	for (i = LASTNUM; i >= FIRSTNUM; i--)
+		if (Num_used[i])
+			return (i);
+
+	return (0);
+}
+
+
+rnum_temp(rnum)
+int	rnum;
+
+/*
+**	Predicate to check whether rnum is a temporary relation or not
+*/
+
+{
+	register int	i;
+
+	i = rnum;
+
+	return (i >= FIRSTNUM || AAbequal(rnum_convert(i), SYSNAME, s_SYSNAME));
+}
+
+rnum_init()
+
+/*
+**	Clear tag fields from previous query
+*/
+
+{
+	register char	*cp;
+	register int	i;
+
+	cp = Num_used;
+	i = FIRSTNUM;
+	while (--i)
+		*cp++ = 0;
+}