Security-55163.44.tar.gz

[apple/security.git] / libsecurity_utilities / lib / timeflow.cpp

diff --git a/libsecurity_utilities/lib/timeflow.cpp b/libsecurity_utilities/lib/timeflow.cpp
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+/*
+ * Copyright (c) 2000-2001,2003-2004 Apple Computer, Inc. All Rights Reserved.
+ * 
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+
+//
+// timeflow - abstract view of the flow of time
+//
+#include "timeflow.h"
+#include <stdint.h>
+#include <math.h>
+
+
+namespace Security {
+namespace Time {
+
+
+//
+// Get "now"
+//
+Absolute now()
+{
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return tv.tv_sec + double(tv.tv_usec) / 1E6;
+}
+
+
+//
+// OOL Conversions
+//
+Absolute::Absolute(const struct timeval &tv)
+{ mValue = tv.tv_sec + double(tv.tv_usec) / 1E6; }
+
+Absolute::Absolute(const struct timespec &tv)
+{ mValue = tv.tv_sec + double(tv.tv_nsec) / 1E9; }
+
+Absolute::operator struct timeval () const
+{
+    struct timeval tv;
+    if (mValue > LONG_MAX) {
+        tv.tv_sec = LONG_MAX;
+        tv.tv_usec = 0;
+    } else {
+        tv.tv_sec = int32_t(mValue);
+        double intPart;
+        tv.tv_usec = int32_t(modf(mValue, &intPart) * 1E6);
+    }
+    return tv;
+}
+
+Absolute::operator struct timespec () const
+{
+    struct timespec ts;
+    if (mValue > LONG_MAX) {
+        ts.tv_sec = LONG_MAX;
+        ts.tv_nsec = 0;
+    } else {
+        ts.tv_sec = time_t(mValue);
+        double intPart;
+        ts.tv_nsec = int32_t(modf(mValue, &intPart) * 1E9);
+    }
+    return ts;
+}
+
+struct timeval Interval::timevalInterval() const
+{
+    struct timeval tv;
+    if (mValue > LONG_MAX) {
+        tv.tv_sec = LONG_MAX;
+        tv.tv_usec = 0;
+    } else if (mValue < 0) {
+        tv.tv_sec = tv.tv_usec = 0;
+    } else {
+        tv.tv_sec = int32_t(mValue);
+        double intPart;
+        tv.tv_usec = int32_t(modf(mValue, &intPart) * 1E6);
+    }
+    return tv;
+}
+
+
+//
+// Estimate resolution at given time.
+//
+// BSD select(2) has theoretical microsecond resolution, but the underlying 
+// Mach system deals with milliseconds, so we report that conservatively.
+// Sometime in the future when the sun is near collapse, residual resolution
+// of a double will drop under 1E-3, but we won't worry about that just yet.
+//
+Interval resolution(Absolute)
+{
+    return 0.001;
+}
+
+
+}      // end namespace Time
+}      // end namespace Security