X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/80e2389990082500d76eb566d4946be3e786c3ef..d8f41ccd20de16f8ebe2ccc84d47bf1cb2b26bbb:/Security/libsecurity_utilities/lib/timeflow.h

diff --git a/Security/libsecurity_utilities/lib/timeflow.h b/Security/libsecurity_utilities/lib/timeflow.h
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+/*
+ * 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