Initial import of the CDE 2.1.30 sources from the Open Group.

cde/lib/tt/mini_isam/isfd.c

@@ -0,0 +1,85 @@
+/*%%  (c) Copyright 1993, 1994 Hewlett-Packard Company			 */
+/*%%  (c) Copyright 1993, 1994 International Business Machines Corp.	 */
+/*%%  (c) Copyright 1993, 1994 Sun Microsystems, Inc.			 */
+/*%%  (c) Copyright 1993, 1994 Novell, Inc. 				 */
+/*%%  $XConsortium: isfd.c /main/3 1995/10/23 11:39:10 rswiston $ 			 				 */
+#ifndef lint
+static char sccsid[] = "@(#)isfd.c 1.3 89/07/17 Copyr 1988 Sun Micro";
+#endif
+/*
+ * Copyright (c) 1988 by Sun Microsystems, Inc.
+ */
+
+/*
+ * isfd.c
+ *
+ * Description:
+ *	The ISAM file descriptors (isfd) are used as index to a table of 
+ *	pointers to File Access Block objects. Isfd.c maintains the table
+ *	of the pointers (isfdtab).
+ *
+ */
+
+#include "isam_impl.h"
+
+static Fab *isfdtab[MAXISFD];		     /* Table of pointers */
+
+
+/*
+ * _isfd_insert(fab)
+ *
+ * Insert a pointer to an Fab object to table of ISAM file descriptors.
+ * Return an ISAM file descriptor, or NOISFD if the table is full.
+ */
+
+Isfd
+_isfd_insert(fab)
+    Fab			*fab;
+{
+    register Isfd	i;
+
+    for (i = 0; i < MAXISFD; i++) {
+	if (isfdtab[i] == NULL)		     /* Empty entry found */
+	    break;
+    }
+
+    if (i == MAXISFD)
+	return (NOISFD);		     /* isfdtab is full */
+
+    isfdtab[i] = fab;
+    return (i);
+}
+
+
+/* 
+ * _isfd_find(isfd) 
+ *
+ * Return a pointer to Fab object associated with the ISAM file 
+ * descriptor isfd. If isfd is not a file descriptor of an open ISAM file,
+ * return NULL.
+ */
+
+Fab *
+_isfd_find(isfd)
+    register Isfd	isfd;
+{
+    if (isfd < 0 || isfd >= MAXISFD || isfdtab[isfd] == NULL)
+	return (NULL);
+    else
+	return (isfdtab[isfd]);
+}
+
+/*
+ * _isfd_delete(isfd)
+ *
+ * Delete an entry from isfdtab. No check is made the entry exists.
+ */
+
+void
+_isfd_delete(isfd)
+    register Isfd	isfd;
+{
+    if (isfd >= 0 && isfd < MAXISFD)
+	isfdtab[isfd] = NULL;
+}
+