--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/genericopenlibs/openenvcore/libc/src/stdtime/difftime.c Fri Jun 04 16:20:51 2010 +0100
@@ -0,0 +1,101 @@
+/*
+* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description:
+*
+*/
+
+
+#include <sys/cdefs.h>
+#ifndef lint
+#ifndef NOID
+static char elsieid[] __unused = "@(#)difftime.c 7.9";
+#endif /* !defined NOID */
+#endif /* !defined lint */
+__FBSDID("$FreeBSD: src/lib/libc/stdtime/difftime.c,v 1.8 2004/06/14 10:31:52 stefanf Exp $");
+
+/*LINTLIBRARY*/
+
+#include "namespace.h"
+#include "private.h"
+#include "un-namespace.h"
+
+/*
+** Algorithm courtesy Paul Eggert (eggert@twinsun.com).
+*/
+
+#ifdef HAVE_LONG_DOUBLE
+#define long_double long double
+#endif /* defined HAVE_LONG_DOUBLE */
+#ifndef HAVE_LONG_DOUBLE
+#define long_double double
+#endif /* !defined HAVE_LONG_DOUBLE */
+
+EXPORT_C
+double
+difftime(time1, time0)
+const time_t time1;
+const time_t time0;
+{
+ time_t delta;
+ time_t hibit;
+
+ {
+ time_t tt;
+ double d;
+ long_double ld;
+
+ if (sizeof tt < sizeof d)
+ return (double) time1 - (double) time0;
+ if (sizeof tt < sizeof ld)
+ return (long_double) time1 - (long_double) time0;
+ }
+ if (time1 < time0)
+ return -difftime(time0, time1);
+ /*
+ ** As much as possible, avoid loss of precision
+ ** by computing the difference before converting to double.
+ */
+ delta = time1 - time0;
+ if (delta >= 0)
+ return delta;
+ /*
+ ** Repair delta overflow.
+ */
+ hibit = (~ (time_t) 0) << (TYPE_BIT(time_t) - 1);
+ /*
+ ** The following expression rounds twice, which means
+ ** the result may not be the closest to the true answer.
+ ** For example, suppose time_t is 64-bit signed int,
+ ** long_double is IEEE 754 double with default rounding,
+ ** time1 = 9223372036854775807 and time0 = -1536.
+ ** Then the true difference is 9223372036854777343,
+ ** which rounds to 9223372036854777856
+ ** with a total error of 513.
+ ** But delta overflows to -9223372036854774273,
+ ** which rounds to -9223372036854774784, and correcting
+ ** this by subtracting 2 * (long_double) hibit
+ ** (i.e. by adding 2**64 = 18446744073709551616)
+ ** yields 9223372036854776832, which
+ ** rounds to 9223372036854775808
+ ** with a total error of 1535 instead.
+ ** This problem occurs only with very large differences.
+ ** It's too painful to fix this portably.
+ ** We are not alone in this problem;
+ ** some C compilers round twice when converting
+ ** large unsigned types to small floating types,
+ ** so if time_t is unsigned the "return delta" above
+ ** has the same double-rounding problem with those compilers.
+ */
+ return delta - 2 * (long_double) hibit;
+}