From 6deb631b20b7e212d9a350759e472fa60f9e92e4 Mon Sep 17 00:00:00 2001
From: David Lawrence <source@isc.org>
Date: Thu, 25 May 2000 03:34:34 +0000
Subject: [PATCH]  208.   [func]          Added ISC_OFFSET_MAXIMUM for the
 maximum value                         of an isc_offset_t.

---
 CHANGES                           |  3 +++
 lib/isc/unix/include/isc/offset.h | 10 ++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index ea262145f2..1df6bba112 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+ 208.   [func]          Added ISC_OFFSET_MAXIMUM for the maximum value
+                        of an isc_offset_t.
+
  207.   [func]		The dnssec tools properly use the logging subsystem.
 
  206.   [cleanup]	dst now stores the key name as a dns_name_t, not
diff --git a/lib/isc/unix/include/isc/offset.h b/lib/isc/unix/include/isc/offset.h
index 5f2b76462e..19d1f18164 100644
--- a/lib/isc/unix/include/isc/offset.h
+++ b/lib/isc/unix/include/isc/offset.h
@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
-/* $Id: offset.h,v 1.3 2000/04/28 22:13:15 tale Exp $ */
+/* $Id: offset.h,v 1.4 2000/05/25 03:34:34 tale Exp $ */
 
 #ifndef ISC_OFFSET_H
 #define ISC_OFFSET_H 1
@@ -23,9 +23,15 @@
 /*
  * File offsets are operating-system dependent.
  */
-
+#include <limits.h>
 #include <sys/types.h>
 
 typedef off_t isc_offset_t;
 
+/*
+ * POSIX says "Additionally, blkcnt_t and off_t are extended signed integral
+ * types", so the maximum value is all 1s except for the high bit.
+ */
+#define ISC_OFFSET_MAXIMUM (~((off_t)1 << (sizeof(off_t) * CHAR_BIT - 1)))
+
 #endif /* ISC_OFFSET_H */