1 files changed, 35 insertions, 0 deletions
diff --git a/pkg/tbtables/tbcnum.x b/pkg/tbtables/tbcnum.x
new file mode 100644
index 00000000..1bf6b90c
--- /dev/null
+++ b/pkg/tbtables/tbcnum.x
@@ -0,0 +1,35 @@
+include "tbtables.h"
+
+# tbcnum -- get column pointer from number
+# This function returns the column pointer corresponding to a given
+# column number, or NULL if the column number is out of range.
+#
+# Phil Hodge,  2-Mar-1998  Map selected column descriptor to actual descriptor.
+
+pointer procedure tbcnum (tp, colnum)
+
+pointer tp			# i: pointer to table descriptor
+int	colnum			# i: column number (not pointer)
+#--
+pointer cp
+pointer tcs_column()
+
+begin
+	# Value to be returned if column number is out of range.
+	cp = NULL
+
+	if (colnum < 1)
+	    return (cp)
+
+	if (TB_COLUMN_SELECT(tp) == YES) {	# column selector was used
+	    if (colnum <= TB_NSEL_COLS(tp)) {
+		cp = tcs_column (TB_SELCOL(tp,colnum))
+	    }
+	} else {				# column selector not used
+	    if (colnum <= TB_NCOLS(tp)) {
+		cp = TB_COLINFO(tp,colnum)
+	    }
+	}
+
+	return (cp)
+end