src/include/gnunet_time_lib.h

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 2, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file include/gnunet_time_lib.h
  23  * @brief functions related to time
  24  *
  25  * @author Christian Grothoff
  26  */
  27
  28 #ifndef GNUNET_TIME_LIB_H
  29 #define GNUNET_TIME_LIB_H
  30
  31 #ifdef __cplusplus
  32 extern "C"
  33 {
  34 #if 0                           /* keep Emacsens' auto-indent happy */
  35 }
  36 #endif
  37 #endif
  38
  39 #include "gnunet_common.h"
  40
  41 /**
  42  * Time for absolute times used by GNUnet, in milliseconds.
  43  */
  44 struct GNUNET_TIME_Absolute
  45 {
  46   uint64_t value;
  47 };
  48
  49 /**
  50  * Time for relative time used by GNUnet, in milliseconds.
  51  * Always positive, so we can only refer to future time.
  52  */
  53 struct GNUNET_TIME_Relative
  54 {
  55   uint64_t value;
  56 };
  57
  58
  59 /**
  60  * Time for relative time used by GNUnet, in milliseconds and in network byte order.
  61  */
  62 struct GNUNET_TIME_RelativeNBO
  63 {
  64   uint64_t value GNUNET_PACKED;
  65 };
  66
  67
  68 /**
  69  * Time for absolute time used by GNUnet, in milliseconds and in network byte order.
  70  */
  71 struct GNUNET_TIME_AbsoluteNBO
  72 {
  73   uint64_t value GNUNET_PACKED;
  74 };
  75
  76 /**
  77  * @brief constants to specify time
  78  */
  79 #define GNUNET_TIME_UNIT_ZERO     GNUNET_TIME_relative_get_zero()
  80 #define GNUNET_TIME_UNIT_MILLISECONDS GNUNET_TIME_relative_get_unit()
  81 #define GNUNET_TIME_UNIT_SECONDS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MILLISECONDS, 1000)
  82 #define GNUNET_TIME_UNIT_MINUTES GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 60)
  83 #define GNUNET_TIME_UNIT_HOURS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 60)
  84 #define GNUNET_TIME_UNIT_DAYS    GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS,   24)
  85 #define GNUNET_TIME_UNIT_WEEKS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,     7)
  86 #define GNUNET_TIME_UNIT_MONTHS  GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,    30)
  87 #define GNUNET_TIME_UNIT_YEARS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,   365)
  88
  89 /**
  90  * Constant used to specify "forever".  This constant
  91  * will be treated specially in all time operations.
  92  */
  93 #define GNUNET_TIME_UNIT_FOREVER_REL GNUNET_TIME_relative_get_forever ()
  94
  95 /**
  96  * Constant used to specify "forever".  This constant
  97  * will be treated specially in all time operations.
  98  */
  99 #define GNUNET_TIME_UNIT_FOREVER_ABS GNUNET_TIME_absolute_get_forever ()
 100
 101 /**
 102  * Return relative time of 0ms.
 103  */
 104 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_zero (void);
 105
 106 /**
 107  * Return relative time of 1ms.
 108  */
 109 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_unit (void);
 110
 111 /**
 112  * Return "forever".
 113  */
 114 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_forever (void);
 115
 116 /**
 117  * Return "forever".
 118  */
 119 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get_forever (void);
 120
 121 /**
 122  * Get the current time.
 123  *
 124  * @return the current time
 125  */
 126 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get (void);
 127
 128 /**
 129  * Convert relative time to an absolute time in the
 130  * future.
 131  *
 132  * @return timestamp that is "rel" in the future, or FOREVER if rel==FOREVER (or if we would overflow)
 133  */
 134 struct GNUNET_TIME_Absolute GNUNET_TIME_relative_to_absolute (struct
 135                                                               GNUNET_TIME_Relative
 136                                                               rel);
 137
 138 /**
 139  * Return the minimum of two relative time values.
 140  *
 141  * @return timestamp that is smaller
 142  */
 143 struct GNUNET_TIME_Relative GNUNET_TIME_relative_min (struct
 144                                                       GNUNET_TIME_Relative
 145                                                       t1,
 146                                                       struct
 147                                                       GNUNET_TIME_Relative t2);
 148
 149 /**
 150  * Given a timestamp in the future, how much time
 151  * remains until then?
 152  *
 153  * @return future - now, or 0 if now >= future, or FOREVER if future==FOREVER.
 154  */
 155 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_remaining (struct
 156                                                                 GNUNET_TIME_Absolute
 157                                                                 future);
 158
 159 /**
 160  * Compute the time difference between the given start and end times.
 161  * Use this function instead of actual subtraction to ensure that
 162  * "FOREVER" and overflows are handeled correctly.
 163  *
 164  * @return 0 if start >= end; FOREVER if end==FOREVER; otherwise end - start
 165  */
 166 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_difference (struct
 167                                                                  GNUNET_TIME_Absolute
 168                                                                  start,
 169                                                                  struct
 170                                                                  GNUNET_TIME_Absolute
 171                                                                  end);
 172
 173 /**
 174  * Get the duration of an operation as the
 175  * difference of the current time and the given start time "hence".
 176  *
 177  * @return aborts if hence==FOREVER, 0 if hence > now, otherwise now-hence.
 178  */
 179 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_duration (struct
 180                                                                GNUNET_TIME_Absolute
 181                                                                hence);
 182
 183
 184 /**
 185  * Add a given relative duration to the
 186  * given start time.
 187  *
 188  * @return FOREVER if either argument is FOREVER or on overflow; start+duration otherwise
 189  */
 190 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_add (struct
 191                                                       GNUNET_TIME_Absolute
 192                                                       start,
 193                                                       struct
 194                                                       GNUNET_TIME_Relative
 195                                                       duration);
 196
 197 /**
 198  * Multiply relative time by a given factor.
 199  *
 200  * @return FOREVER if rel=FOREVER or on overflow; otherwise rel*factor
 201  */
 202 struct GNUNET_TIME_Relative GNUNET_TIME_relative_multiply (struct
 203                                                            GNUNET_TIME_Relative
 204                                                            rel,
 205                                                            unsigned int
 206                                                            factor);
 207
 208 /**
 209  * Add relative times together.
 210  *
 211  * @return FOREVER if either argument is FOREVER or on overflow; a1+a2 otherwise
 212  */
 213 struct GNUNET_TIME_Relative GNUNET_TIME_relative_add (struct
 214                                                       GNUNET_TIME_Relative a1,
 215                                                       struct
 216                                                       GNUNET_TIME_Relative
 217                                                       a2);
 218
 219
 220 /**
 221  * Convert relative time to network byte order.
 222  */
 223 struct GNUNET_TIME_RelativeNBO GNUNET_TIME_relative_hton (struct
 224                                                           GNUNET_TIME_Relative
 225                                                           a);
 226
 227 /**
 228  * Convert relative time from network byte order.
 229  */
 230 struct GNUNET_TIME_Relative GNUNET_TIME_relative_ntoh (struct
 231                                                        GNUNET_TIME_RelativeNBO
 232                                                        a);
 233
 234 /**
 235  * Convert relative time to network byte order.
 236  */
 237 struct GNUNET_TIME_AbsoluteNBO GNUNET_TIME_absolute_hton (struct
 238                                                           GNUNET_TIME_Absolute
 239                                                           a);
 240
 241 /**
 242  * Convert relative time from network byte order.
 243  */
 244 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_ntoh (struct
 245                                                        GNUNET_TIME_AbsoluteNBO
 246                                                        a);
 247
 248 #if 0                           /* keep Emacsens' auto-indent happy */
 249 {
 250 #endif
 251 #ifdef __cplusplus
 252 }
 253 #endif
 254
 255 /* ifndef GNUNET_TIME_LIB_H */
 256 #endif
 257 /* end of gnunet_time_lib.h */