cdsa/cdsa_utilities/timeflow.cpp

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 //
  20 // timeflow - abstract view of the flow of time
  21 //
  22 #include "timeflow.h"
  23 #include <sys/time.h>
  24 #include <math.h>
  25
  26
  27 namespace Security {
  28 namespace Time {
  29
  30
  31 //
  32 // Get "now"
  33 //
  34 Absolute now()
  35 {
  36     struct timeval tv;
  37     gettimeofday(&tv, NULL);
  38     return tv.tv_sec + double(tv.tv_usec) / 1E6;
  39 }
  40
  41
  42 //
  43 // OOL Conversions
  44 //
  45 Absolute::Absolute(const struct timeval &tv)
  46 { mValue = tv.tv_sec + double(tv.tv_usec) / 1E6; }
  47
  48 Absolute::Absolute(const struct timespec &tv)
  49 { mValue = tv.tv_sec + double(tv.tv_nsec) / 1E9; }
  50
  51 Absolute::operator struct timeval () const
  52 {
  53     struct timeval tv;
  54     if (mValue > LONG_MAX) {
  55         tv.tv_sec = LONG_MAX;
  56         tv.tv_usec = 0;
  57     } else {
  58         tv.tv_sec = int32_t(mValue);
  59         double intPart;
  60         tv.tv_usec = int32_t(modf(mValue, &intPart) * 1E6);
  61     }
  62     return tv;
  63 }
  64
  65 Absolute::operator struct timespec () const
  66 {
  67     struct timespec ts;
  68     if (mValue > LONG_MAX) {
  69         ts.tv_sec = LONG_MAX;
  70         ts.tv_nsec = 0;
  71     } else {
  72         ts.tv_sec = time_t(mValue);
  73         double intPart;
  74         ts.tv_nsec = int32_t(modf(mValue, &intPart) * 1E9);
  75     }
  76     return ts;
  77 }
  78
  79 struct timeval Interval::timevalInterval() const
  80 {
  81     struct timeval tv;
  82     if (mValue > LONG_MAX) {
  83         tv.tv_sec = LONG_MAX;
  84         tv.tv_usec = 0;
  85     } else if (mValue < 0) {
  86         tv.tv_sec = tv.tv_usec = 0;
  87     } else {
  88         tv.tv_sec = int32_t(mValue);
  89         double intPart;
  90         tv.tv_usec = int32_t(modf(mValue, &intPart) * 1E6);
  91     }
  92     return tv;
  93 }
  94
  95
  96 //
  97 // Estimate resolution at given time.
  98 //
  99 // BSD select(2) has theoretical microsecond resolution, but the underlying
 100 // Mach system deals with milliseconds, so we report that conservatively.
 101 // Sometime in the future when the sun is near collapse, residual resolution
 102 // of a double will drop under 1E-3, but we won't worry about that just yet.
 103 //
 104 Interval resolution(Absolute)
 105 {
 106     return 0.001;
 107 }
 108
 109
 110 }       // end namespace Time
 111 }       // end namespace Security