--- /dev/null
+/*
+ * Copyright (c) 2000-2001,2003-2004,2011,2014 Apple 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
+//
+// We happily publish both absolute and relative times as floating-point values.
+// Absolute times are off the UNIX Epoch (1/1/1970, midnight). This leaves us about
+// microsecond resolution in Modern Times.
+//
+#ifndef _H_TIMEFLOW
+#define _H_TIMEFLOW
+
+#include <sys/time.h>
+#include <limits.h>
+#include <math.h> // for MAXFLOAT
+
+
+namespace Security {
+namespace Time {
+
+
+//
+// A Time::Interval is a time difference (distance).
+//
+class Interval {
+ friend class Absolute;
+public:
+ Interval() { }
+ Interval(int seconds) { mValue = seconds; }
+ Interval(double seconds) { mValue = seconds; }
+ explicit Interval(time_t seconds) { mValue = seconds; }
+
+ Interval &operator += (Interval rel) { mValue += rel.mValue; return *this; }
+ Interval &operator -= (Interval rel) { mValue -= rel.mValue; return *this; }
+ Interval &operator *= (double f) { mValue *= f; return *this; }
+ Interval &operator /= (double f) { mValue /= f; return *this; }
+
+ bool operator < (Interval other) const { return mValue < other.mValue; }
+ bool operator <= (Interval other) const { return mValue <= other.mValue; }
+ bool operator > (Interval other) const { return mValue > other.mValue; }
+ bool operator >= (Interval other) const { return mValue >= other.mValue; }
+ bool operator == (Interval other) const { return mValue == other.mValue; }
+ bool operator != (Interval other) const { return mValue != other.mValue; }
+
+ // express as (fractions of) seconds, milliseconds, or microseconds
+ double seconds() const { return mValue; }
+ double mSeconds() const { return mValue * 1E3; }
+ double uSeconds() const { return mValue * 1E6; }
+
+ // struct timeval is sometimes used for time intervals, but not often - so be explicit
+ struct timeval timevalInterval() const;
+
+private:
+ double mValue;
+};
+
+
+//
+// A Time::Absolute is a moment in time.
+//
+class Absolute {
+ friend class Interval;
+ friend Interval operator - (Absolute, Absolute);
+ friend Absolute now();
+ friend Absolute bigBang();
+ friend Absolute heatDeath();
+public:
+ Absolute() { } // uninitialized
+ Absolute(time_t t) { mValue = t; } // from time_t
+ Absolute(const struct timeval &tv); // from timeval
+ Absolute(const struct timespec &ts); // from timespec
+
+ // *crement operators
+ Absolute &operator += (Interval rel) { mValue += rel.mValue; return *this; }
+ Absolute &operator -= (Interval rel) { mValue -= rel.mValue; return *this; }
+
+ // comparisons
+ bool operator < (Absolute other) const { return mValue < other.mValue; }
+ bool operator <= (Absolute other) const { return mValue <= other.mValue; }
+ bool operator > (Absolute other) const { return mValue > other.mValue; }
+ bool operator >= (Absolute other) const { return mValue >= other.mValue; }
+ bool operator == (Absolute other) const { return mValue == other.mValue; }
+ bool operator != (Absolute other) const { return mValue != other.mValue; }
+
+ // express as conventional (absolute!) time measures
+ operator struct timeval() const;
+ operator struct timespec() const;
+ operator time_t () const { return time_t(mValue); }
+
+ // internal form for debugging ONLY
+ double internalForm() const { return mValue; }
+
+private:
+ double mValue;
+
+ Absolute(double value) : mValue(value) { }
+};
+
+
+//
+// Time::now produces the current time
+//
+Absolute now(); // get "now"
+
+
+//
+// Time::resolution(when) gives a conservative estimate of the available resolution
+// at a given time.
+//
+Interval resolution(Absolute at); // estimate available resolution at given time
+
+
+//
+// Some useful "constants"
+//
+inline Absolute bigBang() { return -MAXFLOAT; }
+inline Absolute heatDeath() { return +MAXFLOAT; }
+
+
+
+//
+// More inline arithmetic
+//
+inline Interval operator + (Interval r, Interval r2) { r += r2; return r; }
+inline Interval operator - (Interval r, Interval r2) { r -= r2; return r; }
+inline Interval operator * (Interval r, double f) { r *= f; return r; }
+inline Interval operator / (Interval r, double f) { r /= f; return r; }
+
+inline Absolute operator + (Absolute a, Interval r) { return a += r; }
+inline Absolute operator + (Interval r, Absolute a) { return a += r; }
+inline Absolute operator - (Absolute a, Interval r) { return a -= r; }
+
+inline Interval operator - (Absolute t1, Absolute t0)
+{ return t1.mValue - t0.mValue; }
+
+
+} // end namespace Time
+} // end namespace Security
+
+#endif //_H_TIMEFLOW
projects / apple / security.git / blobdiff