ltt/branches/poly/ltt/time.h

   1 /* This file is part of the Linux Trace Toolkit trace reading library
   2  * Copyright (C) 2003-2004 Michel Dagenais
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License Version 2.1 as published by the Free Software Foundation.
   7  *
   8  * This library is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 02111-1307, USA.
  17  */
  18
  19 #ifndef LTT_TIME_H
  20 #define LTT_TIME_H
  21
  22 #include <glib.h>
  23
  24
  25 typedef struct _LttTime {
  26   unsigned long tv_sec;
  27   unsigned long tv_nsec;
  28 } LttTime;
  29
  30
  31 static const unsigned long NANOSECONDS_PER_SECOND = 1000000000;
  32
  33 static const LttTime ltt_time_zero = { 0, 0};
  34
  35 static const LttTime ltt_time_one = { 0, 1 };
  36
  37 static const LttTime ltt_time_infinite = { G_MAXUINT, G_MAXUINT };
  38
  39 static inline LttTime ltt_time_sub(LttTime t1, LttTime t2)
  40 {
  41   LttTime res;
  42   res.tv_sec  = t1.tv_sec  - t2.tv_sec;
  43   if(t1.tv_nsec < t2.tv_nsec) {
  44     res.tv_sec--;
  45     res.tv_nsec = NANOSECONDS_PER_SECOND + t1.tv_nsec - t2.tv_nsec;
  46   }
  47   else {
  48     res.tv_nsec = t1.tv_nsec - t2.tv_nsec;
  49   }
  50   return res;
  51 }
  52
  53
  54 static inline LttTime ltt_time_add(LttTime t1, LttTime t2)
  55 {
  56   LttTime res;
  57   res.tv_sec  = t1.tv_sec  + t2.tv_sec;
  58   res.tv_nsec = t1.tv_nsec + t2.tv_nsec;
  59   if(res.tv_nsec >= NANOSECONDS_PER_SECOND) {
  60     res.tv_sec++;
  61     res.tv_nsec -= NANOSECONDS_PER_SECOND;
  62   }
  63   return res;
  64 }
  65
  66
  67 static inline LttTime ltt_time_mul(LttTime t1, float f)
  68 {
  69   LttTime res;
  70   float d;
  71   double sec;
  72
  73   if(f == 0.0){
  74     res.tv_sec = 0;
  75     res.tv_nsec = 0;
  76   }else{
  77     d = 1.0/f;
  78     sec = t1.tv_sec / (double)d;
  79     res.tv_sec = sec;
  80     res.tv_nsec = t1.tv_nsec / (double)d + (sec - res.tv_sec) *
  81                   NANOSECONDS_PER_SECOND;
  82     res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
  83     res.tv_nsec %= NANOSECONDS_PER_SECOND;
  84   }
  85   return res;
  86 }
  87
  88
  89 static inline LttTime ltt_time_div(LttTime t1, float f)
  90 {
  91   double sec;
  92   LttTime res;
  93
  94   sec = t1.tv_sec / (double)f;
  95   res.tv_sec = sec;
  96   res.tv_nsec = t1.tv_nsec / (double)f + (sec - res.tv_sec) *
  97       NANOSECONDS_PER_SECOND;
  98   res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
  99   res.tv_nsec %= NANOSECONDS_PER_SECOND;
 100   return res;
 101 }
 102
 103
 104 static inline int ltt_time_compare(LttTime t1, LttTime t2)
 105 {
 106   if(t1.tv_sec > t2.tv_sec) return 1;
 107   if(t1.tv_sec < t2.tv_sec) return -1;
 108   if(t1.tv_nsec > t2.tv_nsec) return 1;
 109   if(t1.tv_nsec < t2.tv_nsec) return -1;
 110   return 0;
 111 }
 112
 113 #define MAX_TV_SEC_TO_DOUBLE 0x7FFFFF
 114 static inline double ltt_time_to_double(LttTime t1)
 115 {
 116   /* We lose precision if tv_sec is > than (2^23)-1
 117    *
 118    * Max values that fits in a double (53 bits precision on normalised
 119    * mantissa):
 120    * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
 121    *
 122    * So we have 53-30 = 23 bits left for tv_sec.
 123    * */
 124   g_assert(t1.tv_sec <= MAX_TV_SEC_TO_DOUBLE);
 125   if(t1.tv_sec > MAX_TV_SEC_TO_DOUBLE)
 126     g_warning("Precision loss in conversion LttTime to double");
 127   return (double)t1.tv_sec + (double)t1.tv_nsec / NANOSECONDS_PER_SECOND;
 128 }
 129
 130
 131 static inline LttTime ltt_time_from_double(double t1)
 132 {
 133   /* We lose precision if tv_sec is > than (2^23)-1
 134    *
 135    * Max values that fits in a double (53 bits precision on normalised
 136    * mantissa):
 137    * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
 138    *
 139    * So we have 53-30 = 23 bits left for tv_sec.
 140    * */
 141   g_assert(t1 <= MAX_TV_SEC_TO_DOUBLE);
 142   if(t1 > MAX_TV_SEC_TO_DOUBLE)
 143     g_warning("Conversion from non precise double to LttTime");
 144   LttTime res;
 145   res.tv_sec = t1;
 146   res.tv_nsec = (t1 - res.tv_sec) * NANOSECONDS_PER_SECOND;
 147   return res;
 148 }
 149
 150 #endif // LTT_TIME_H