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 #define 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, NANOSECONDS_PER_SECOND };
  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   res.tv_nsec = t1.tv_nsec - t2.tv_nsec;
  44   if(t1.tv_nsec < t2.tv_nsec) {
  45     res.tv_sec--;
  46     res.tv_nsec += NANOSECONDS_PER_SECOND;
  47   }
  48   return res;
  49 }
  50
  51
  52 static inline LttTime ltt_time_add(LttTime t1, LttTime t2)
  53 {
  54   LttTime res;
  55   res.tv_nsec = t1.tv_nsec + t2.tv_nsec;
  56   res.tv_sec = t1.tv_sec + t2.tv_sec;
  57   if(res.tv_nsec >= NANOSECONDS_PER_SECOND) {
  58     res.tv_sec++;
  59     res.tv_nsec -= NANOSECONDS_PER_SECOND;
  60   }
  61   return res;
  62 }
  63
  64
  65 static inline int ltt_time_compare(LttTime t1, LttTime t2)
  66 {
  67   if(t1.tv_sec > t2.tv_sec) return 1;
  68   if(t1.tv_sec < t2.tv_sec) return -1;
  69   if(t1.tv_nsec > t2.tv_nsec) return 1;
  70   if(t1.tv_nsec < t2.tv_nsec) return -1;
  71   return 0;
  72 }
  73
  74 #define LTT_TIME_MIN(a,b) ((ltt_time_compare((a),(b)) < 0) ? (a) : (b))
  75 #define LTT_TIME_MAX(a,b) ((ltt_time_compare((a),(b)) > 0) ? (a) : (b))
  76
  77 #define MAX_TV_SEC_TO_DOUBLE 0x7FFFFF
  78 static inline double ltt_time_to_double(LttTime t1)
  79 {
  80   /* We lose precision if tv_sec is > than (2^23)-1
  81    *
  82    * Max values that fits in a double (53 bits precision on normalised
  83    * mantissa):
  84    * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
  85    *
  86    * So we have 53-30 = 23 bits left for tv_sec.
  87    * */
  88 #ifdef EXTRA_CHECK
  89   g_assert(t1.tv_sec <= MAX_TV_SEC_TO_DOUBLE);
  90   if(t1.tv_sec > MAX_TV_SEC_TO_DOUBLE)
  91     g_warning("Precision loss in conversion LttTime to double");
  92 #endif //EXTRA_CHECK
  93   return ((double)t1.tv_sec * (double)NANOSECONDS_PER_SECOND) + (double)t1.tv_nsec;
  94 }
  95
  96
  97 static inline LttTime ltt_time_from_double(double t1)
  98 {
  99   /* We lose precision if tv_sec is > than (2^23)-1
 100    *
 101    * Max values that fits in a double (53 bits precision on normalised
 102    * mantissa):
 103    * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
 104    *
 105    * So we have 53-30 = 23 bits left for tv_sec.
 106    * */
 107 #ifdef EXTRA_CHECK
 108   g_assert(t1 <= MAX_TV_SEC_TO_DOUBLE);
 109   if(t1 > MAX_TV_SEC_TO_DOUBLE)
 110     g_warning("Conversion from non precise double to LttTime");
 111 #endif //EXTRA_CHECK
 112   LttTime res;
 113   res.tv_sec = t1/(double)NANOSECONDS_PER_SECOND;
 114   res.tv_nsec = (t1 - (res.tv_sec*NANOSECONDS_PER_SECOND));
 115   return res;
 116 }
 117
 118 /* Use ltt_time_to_double and ltt_time_from_double to check for lack
 119  * of precision.
 120  */
 121 static inline LttTime ltt_time_mul(LttTime t1, double d)
 122 {
 123   LttTime res;
 124
 125   double time_double = ltt_time_to_double(t1);
 126
 127   time_double = time_double * d;
 128
 129   res = ltt_time_from_double(time_double);
 130
 131   return res;
 132
 133 #if 0
 134   /* What is that ? (Mathieu) */
 135   if(f == 0.0){
 136     res.tv_sec = 0;
 137     res.tv_nsec = 0;
 138   }else{
 139   double d;
 140     d = 1.0/f;
 141     sec = t1.tv_sec / (double)d;
 142     res.tv_sec = sec;
 143     res.tv_nsec = t1.tv_nsec / (double)d + (sec - res.tv_sec) *
 144                   NANOSECONDS_PER_SECOND;
 145     res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
 146     res.tv_nsec %= NANOSECONDS_PER_SECOND;
 147   }
 148   return res;
 149 #endif //0
 150 }
 151
 152
 153 /* Use ltt_time_to_double and ltt_time_from_double to check for lack
 154  * of precision.
 155  */
 156 static inline LttTime ltt_time_div(LttTime t1, double d)
 157 {
 158   LttTime res;
 159
 160   double time_double = ltt_time_to_double(t1);
 161
 162   time_double = time_double / d;
 163
 164   res = ltt_time_from_double(time_double);
 165
 166   return res;
 167
 168
 169 #if 0
 170   double sec;
 171   LttTime res;
 172
 173   sec = t1.tv_sec / (double)f;
 174   res.tv_sec = sec;
 175   res.tv_nsec = t1.tv_nsec / (double)f + (sec - res.tv_sec) *
 176       NANOSECONDS_PER_SECOND;
 177   res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
 178   res.tv_nsec %= NANOSECONDS_PER_SECOND;
 179   return res;
 180 #endif //0
 181 }
 182
 183 static inline guint64 ltt_time_to_uint64(LttTime t1)
 184 {
 185   return (guint64)t1.tv_sec*NANOSECONDS_PER_SECOND
 186             + (guint64)t1.tv_nsec;
 187 }
 188
 189
 190 #define MAX_TV_SEC_TO_UINT64 0x3FFFFFFFFFFFFFFFULL
 191 static inline LttTime ltt_time_from_uint64(guint64 t1)
 192 {
 193   /* We lose precision if tv_sec is > than (2^62)-1
 194    * */
 195 #ifdef EXTRA_CHECK
 196   g_assert(t1 <= MAX_TV_SEC_TO_UINT64);
 197   if(t1 > MAX_TV_SEC_TO_UINT64)
 198     g_warning("Conversion from non precise uint64 to LttTime");
 199 #endif //EXTRA_CHECK
 200   LttTime res;
 201   res.tv_sec = t1/NANOSECONDS_PER_SECOND;
 202   res.tv_nsec = (t1 - res.tv_sec*NANOSECONDS_PER_SECOND);
 203   return res;
 204 }
 205
 206 #endif // LTT_TIME_H