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 #define SHIFT_CONST 1.07374182400631629848
  33
  34 static const LttTime ltt_time_zero = { 0, 0 };
  35
  36 static const LttTime ltt_time_one = { 0, 1 };
  37
  38 static const LttTime ltt_time_infinite = { G_MAXUINT, NANOSECONDS_PER_SECOND };
  39
  40 static inline LttTime ltt_time_sub(LttTime t1, LttTime t2)
  41 {
  42   LttTime res;
  43   res.tv_sec  = t1.tv_sec  - t2.tv_sec;
  44   res.tv_nsec = t1.tv_nsec - t2.tv_nsec;
  45   if(t1.tv_nsec < t2.tv_nsec) {
  46     res.tv_sec--;
  47     res.tv_nsec += NANOSECONDS_PER_SECOND;
  48   }
  49   return res;
  50 }
  51
  52
  53 static inline LttTime ltt_time_add(LttTime t1, LttTime t2)
  54 {
  55   LttTime res;
  56   res.tv_nsec = t1.tv_nsec + t2.tv_nsec;
  57   res.tv_sec = t1.tv_sec + t2.tv_sec;
  58   if(res.tv_nsec >= NANOSECONDS_PER_SECOND) {
  59     res.tv_sec++;
  60     res.tv_nsec -= NANOSECONDS_PER_SECOND;
  61   }
  62   return res;
  63 }
  64
  65
  66 /* Fastest comparison : t1 > t2 */
  67 static inline int ltt_time_compare(LttTime t1, LttTime t2)
  68 {
  69   int ret=0;
  70   if(t1.tv_sec > t2.tv_sec) ret = 1;
  71   else if(t1.tv_sec < t2.tv_sec) ret = -1;
  72   else if(t1.tv_nsec > t2.tv_nsec) ret = 1;
  73   else if(t1.tv_nsec < t2.tv_nsec) ret = -1;
  74
  75   return ret;
  76 }
  77
  78 #define LTT_TIME_MIN(a,b) ((ltt_time_compare((a),(b)) < 0) ? (a) : (b))
  79 #define LTT_TIME_MAX(a,b) ((ltt_time_compare((a),(b)) > 0) ? (a) : (b))
  80
  81 #define MAX_TV_SEC_TO_DOUBLE 0x7FFFFF
  82 static inline double ltt_time_to_double(LttTime t1)
  83 {
  84   /* We lose precision if tv_sec is > than (2^23)-1
  85    *
  86    * Max values that fits in a double (53 bits precision on normalised
  87    * mantissa):
  88    * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
  89    *
  90    * So we have 53-30 = 23 bits left for tv_sec.
  91    * */
  92 #ifdef EXTRA_CHECK
  93   g_assert(t1.tv_sec <= MAX_TV_SEC_TO_DOUBLE);
  94   if(t1.tv_sec > MAX_TV_SEC_TO_DOUBLE)
  95     g_warning("Precision loss in conversion LttTime to double");
  96 #endif //EXTRA_CHECK
  97   return ((double)t1.tv_sec * (double)NANOSECONDS_PER_SECOND) + (double)t1.tv_nsec;
  98 }
  99
 100
 101 static inline LttTime ltt_time_from_double(double t1)
 102 {
 103   /* We lose precision if tv_sec is > than (2^23)-1
 104    *
 105    * Max values that fits in a double (53 bits precision on normalised
 106    * mantissa):
 107    * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
 108    *
 109    * So we have 53-30 = 23 bits left for tv_sec.
 110    * */
 111 #ifdef EXTRA_CHECK
 112   g_assert(t1 <= MAX_TV_SEC_TO_DOUBLE);
 113   if(t1 > MAX_TV_SEC_TO_DOUBLE)
 114     g_warning("Conversion from non precise double to LttTime");
 115 #endif //EXTRA_CHECK
 116   LttTime res;
 117   //res.tv_sec = t1/(double)NANOSECONDS_PER_SECOND;
 118   res.tv_sec = (guint64)(t1 * SHIFT_CONST) >> 30;
 119   res.tv_nsec = (t1 - (res.tv_sec*NANOSECONDS_PER_SECOND));
 120   return res;
 121 }
 122
 123 /* Use ltt_time_to_double and ltt_time_from_double to check for lack
 124  * of precision.
 125  */
 126 static inline LttTime ltt_time_mul(LttTime t1, double d)
 127 {
 128   LttTime res;
 129
 130   double time_double = ltt_time_to_double(t1);
 131
 132   time_double = time_double * d;
 133
 134   res = ltt_time_from_double(time_double);
 135
 136   return res;
 137
 138 #if 0
 139   /* What is that ? (Mathieu) */
 140   if(f == 0.0){
 141     res.tv_sec = 0;
 142     res.tv_nsec = 0;
 143   }else{
 144   double d;
 145     d = 1.0/f;
 146     sec = t1.tv_sec / (double)d;
 147     res.tv_sec = sec;
 148     res.tv_nsec = t1.tv_nsec / (double)d + (sec - res.tv_sec) *
 149                   NANOSECONDS_PER_SECOND;
 150     res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
 151     res.tv_nsec %= NANOSECONDS_PER_SECOND;
 152   }
 153   return res;
 154 #endif //0
 155 }
 156
 157
 158 /* Use ltt_time_to_double and ltt_time_from_double to check for lack
 159  * of precision.
 160  */
 161 static inline LttTime ltt_time_div(LttTime t1, double d)
 162 {
 163   LttTime res;
 164
 165   double time_double = ltt_time_to_double(t1);
 166
 167   time_double = time_double / d;
 168
 169   res = ltt_time_from_double(time_double);
 170
 171   return res;
 172
 173
 174 #if 0
 175   double sec;
 176   LttTime res;
 177
 178   sec = t1.tv_sec / (double)f;
 179   res.tv_sec = sec;
 180   res.tv_nsec = t1.tv_nsec / (double)f + (sec - res.tv_sec) *
 181       NANOSECONDS_PER_SECOND;
 182   res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
 183   res.tv_nsec %= NANOSECONDS_PER_SECOND;
 184   return res;
 185 #endif //0
 186 }
 187
 188 static inline guint64 ltt_time_to_uint64(LttTime t1)
 189 {
 190   return (guint64)t1.tv_sec*NANOSECONDS_PER_SECOND
 191             + (guint64)t1.tv_nsec;
 192 }
 193
 194
 195 #define MAX_TV_SEC_TO_UINT64 0x3FFFFFFFFFFFFFFFULL
 196 static inline LttTime ltt_time_from_uint64(guint64 t1)
 197 {
 198   /* We lose precision if tv_sec is > than (2^62)-1
 199    * */
 200 #ifdef EXTRA_CHECK
 201   g_assert(t1 <= MAX_TV_SEC_TO_UINT64);
 202   if(t1 > MAX_TV_SEC_TO_UINT64)
 203     g_warning("Conversion from non precise uint64 to LttTime");
 204 #endif //EXTRA_CHECK
 205   LttTime res;
 206   res.tv_sec = t1/NANOSECONDS_PER_SECOND;
 207   res.tv_nsec = (t1 - res.tv_sec*NANOSECONDS_PER_SECOND);
 208   return res;
 209 }
 210
 211 #endif // LTT_TIME_H