ING_DB

WEGA/contrib/ingres/dbs/src/eql/getch.c

@@ -0,0 +1,167 @@
+# include	<stdio.h>
+# include	"gen.h"
+# include	"constants.h"
+# include	"globals.h"
+
+char		*Line_pos;		/* position in input line	    */
+char		Line_buf[MAXSTRING + 1];	/* buffer for input line    */
+
+static int	Peekc[2] =	{-1,-1};
+
+/*
+**  GETCH.C -- I/O manipulation routines
+**
+**	Defines:
+**		getch()
+**		backup()
+**		int Peekc[2]  -- 2 char stack, if[0]  != -1, the character to
+**			be returned on the next call to getch().
+**		char *Line_pos -- if != 0 *Line_pos is next
+**			character that should be returned.
+**		char Line_buf[MAXSTRING + 1] -- holds current
+**			input line's text.
+**
+**
+**
+** initializes peek buffer to be empty
+*/
+
+/*
+**  GETCH -- Get a character from the input stream
+**
+**	Returns:
+**		the next character on the input stream, or
+**		the backed up character if there is one.
+**		EOF_TOK is returned on EOF.
+**
+**	Side Effects:
+**		If a backed up character exists, unloads it.
+**		*Line_pos is returned if Line_pos != 0
+**		and no backup character exists. Line_buf
+**		contains the line from which characters are being
+**		returned. A call with Line_pos == 0 forces
+**		reading of the next input line. Yyline is
+**		incremented when a newline is returned.
+**		If an EOF is in the middle of a line,
+**		then a newline will be appended.
+*/
+getch()
+{
+	register char	*cp;
+	register int	ch;
+	static		eoflag;
+	extern int	yyline;
+
+	if (Peekc[0] >= 0)
+	{
+		/* have a backed up character */
+		ch = Peekc[0];
+		if (ch == '\n')
+			yyline += 1;
+		Peekc[0] = Peekc[1];
+		Peekc[1] = -1;
+	}
+	else
+	{
+		for ( ; ; )
+		{
+			/* no lookahead character */
+			if (!Line_pos)
+			{
+				if (eoflag)
+				{
+					eoflag = 0;
+
+					/* try to restore previous file */
+					if (!restoref())
+						return (0);
+#					ifdef xDEBUG
+					if (Chardebug || Lex_debug)
+						printf("include file - pop\n");
+#					endif
+				}
+				for (cp = Line_buf; (*cp = getc(In_file)) != '\n'
+						    && ctoi(*cp) != EOF; cp++)
+				{
+					if (cp - Line_buf > sizeof Line_buf - 1)
+					{
+						printf("WARNING : line %d too long, broken in two\n",
+						yyline);
+						break;
+					}
+				}
+				if (ctoi(*cp) == EOF)
+				{
+					eoflag++;
+					if (cp == Line_buf)
+						/* EOF after '\n' */
+						continue;
+					/* EOF in middle of line */
+					*cp = '\n';
+				}
+				Line_pos = Line_buf;
+
+				/* test for a "#include" line */
+				if (tst_include())
+				{
+					/* Force reloading Line_buf */
+					Line_pos = 0;
+					eoflag = 0;
+#					ifdef xDEBUG
+					if (Chardebug || Lex_debug)
+						printf("include file - push\n");
+#					endif
+					continue;
+				}
+			}
+			cp =  Line_pos;
+			if (*cp == '\n')
+			{
+				Line_pos = 0;
+				yyline += 1;
+			}
+			else
+				Line_pos++;
+			ch = *cp;
+			break;
+		}
+	}
+	ch = ctou(ch);
+
+#	ifdef xDEBUG
+	if (Chardebug)
+		printf("getch - returning '%c'.\n", ch);
+#	endif
+
+	return (ch);
+}
+
+
+/*
+**  BACKUP -- Back up a character on the input stream.
+**	Backs up a single character into Peekc.
+**
+**	Parameters:
+**		ch - character to back up
+**
+**	Side Effects:
+**		pushes Peekc[0] to Peekc[1].
+**		sets Peekc[0] to backed up character.
+*/
+backup(ch)
+register int	ch;
+{
+	extern int	yyline;
+
+#	ifdef xDEBUG
+	if (Chardebug)
+		printf("backed up : '%c'\n", ch);
+#	endif
+
+	if (Peekc[1] >= 0)
+		AAsyserr(13002, yyline, Peekc[0], Peekc[1], ch);
+
+	Peekc[1] = Peekc[0];
+	if ((Peekc[0] = ctou(ch)) == '\n')
+		--yyline;
+}