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 #define likely(x) __builtin_expect(!!(x), 1)
  66 #define unlikely(x) __builtin_expect(!!(x), 0)
  67
  68 /* Fastest comparison : t1 > t2 */
  69 static inline int ltt_time_compare(LttTime t1, LttTime t2)
  70 {
  71   int ret=0;
  72   if(likely(t1.tv_sec > t2.tv_sec)) ret = 1;
  73   else if(unlikely(t1.tv_sec < t2.tv_sec)) ret = -1;
  74   else if(likely(t1.tv_nsec > t2.tv_nsec)) ret = 1;
  75   else if(unlikely(t1.tv_nsec < t2.tv_nsec)) ret = -1;
  76
  77   return ret;
  78 }
  79
  80 #define LTT_TIME_MIN(a,b) ((ltt_time_compare((a),(b)) < 0) ? (a) : (b))
  81 #define LTT_TIME_MAX(a,b) ((ltt_time_compare((a),(b)) > 0) ? (a) : (b))
  82
  83 #define MAX_TV_SEC_TO_DOUBLE 0x7FFFFF
  84 static inline double ltt_time_to_double(LttTime t1)
  85 {
  86   /* We lose precision if tv_sec is > than (2^23)-1
  87    *
  88    * Max values that fits in a double (53 bits precision on normalised
  89    * mantissa):
  90    * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
  91    *
  92    * So we have 53-30 = 23 bits left for tv_sec.
  93    * */
  94 #ifdef EXTRA_CHECK
  95   g_assert(t1.tv_sec <= MAX_TV_SEC_TO_DOUBLE);
  96   if(t1.tv_sec > MAX_TV_SEC_TO_DOUBLE)
  97     g_warning("Precision loss in conversion LttTime to double");
  98 #endif //EXTRA_CHECK
  99   return ((double)t1.tv_sec * (double)NANOSECONDS_PER_SECOND) + (double)t1.tv_nsec;
 100 }
 101
 102
 103 static inline LttTime ltt_time_from_double(double t1)
 104 {
 105   /* We lose precision if tv_sec is > than (2^23)-1
 106    *
 107    * Max values that fits in a double (53 bits precision on normalised
 108    * mantissa):
 109    * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
 110    *
 111    * So we have 53-30 = 23 bits left for tv_sec.
 112    * */
 113 #ifdef EXTRA_CHECK
 114   g_assert(t1 <= MAX_TV_SEC_TO_DOUBLE);
 115   if(t1 > MAX_TV_SEC_TO_DOUBLE)
 116     g_warning("Conversion from non precise double to LttTime");
 117 #endif //EXTRA_CHECK
 118   LttTime res;
 119   //res.tv_sec = t1/(double)NANOSECONDS_PER_SECOND;
 120   res.tv_sec = (guint64)(t1 * SHIFT_CONST) >> 30;
 121   res.tv_nsec = (t1 - (res.tv_sec*NANOSECONDS_PER_SECOND));
 122   return res;
 123 }
 124
 125 /* Use ltt_time_to_double and ltt_time_from_double to check for lack
 126  * of precision.
 127  */
 128 static inline LttTime ltt_time_mul(LttTime t1, double d)
 129 {
 130   LttTime res;
 131
 132   double time_double = ltt_time_to_double(t1);
 133
 134   time_double = time_double * d;
 135
 136   res = ltt_time_from_double(time_double);
 137
 138   return res;
 139
 140 #if 0
 141   /* What is that ? (Mathieu) */
 142   if(f == 0.0){
 143     res.tv_sec = 0;
 144     res.tv_nsec = 0;
 145   }else{
 146   double d;
 147     d = 1.0/f;
 148     sec = t1.tv_sec / (double)d;
 149     res.tv_sec = sec;
 150     res.tv_nsec = t1.tv_nsec / (double)d + (sec - res.tv_sec) *
 151                   NANOSECONDS_PER_SECOND;
 152     res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
 153     res.tv_nsec %= NANOSECONDS_PER_SECOND;
 154   }
 155   return res;
 156 #endif //0
 157 }
 158
 159
 160 /* Use ltt_time_to_double and ltt_time_from_double to check for lack
 161  * of precision.
 162  */
 163 static inline LttTime ltt_time_div(LttTime t1, double d)
 164 {
 165   LttTime res;
 166
 167   double time_double = ltt_time_to_double(t1);
 168
 169   time_double = time_double / d;
 170
 171   res = ltt_time_from_double(time_double);
 172
 173   return res;
 174
 175
 176 #if 0
 177   double sec;
 178   LttTime res;
 179
 180   sec = t1.tv_sec / (double)f;
 181   res.tv_sec = sec;
 182   res.tv_nsec = t1.tv_nsec / (double)f + (sec - res.tv_sec) *
 183       NANOSECONDS_PER_SECOND;
 184   res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
 185   res.tv_nsec %= NANOSECONDS_PER_SECOND;
 186   return res;
 187 #endif //0
 188 }
 189
 190 static inline guint64 ltt_time_to_uint64(LttTime t1)
 191 {
 192   return (guint64)t1.tv_sec*NANOSECONDS_PER_SECOND
 193             + (guint64)t1.tv_nsec;
 194 }
 195
 196
 197 #define MAX_TV_SEC_TO_UINT64 0x3FFFFFFFFFFFFFFFULL
 198 static inline LttTime ltt_time_from_uint64(guint64 t1)
 199 {
 200   /* We lose precision if tv_sec is > than (2^62)-1
 201    * */
 202 #ifdef EXTRA_CHECK
 203   g_assert(t1 <= MAX_TV_SEC_TO_UINT64);
 204   if(t1 > MAX_TV_SEC_TO_UINT64)
 205     g_warning("Conversion from non precise uint64 to LttTime");
 206 #endif //EXTRA_CHECK
 207   LttTime res;
 208   res.tv_sec = t1/NANOSECONDS_PER_SECOND;
 209   res.tv_nsec = (t1 - res.tv_sec*NANOSECONDS_PER_SECOND);
 210   return res;
 211 }
 212
 213 #endif // LTT_TIME_H