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 /**
  78  * @brief constants to specify time
  79  */
  80 #define GNUNET_TIME_UNIT_ZERO     GNUNET_TIME_relative_get_zero()
  81 #define GNUNET_TIME_UNIT_ZERO_ABS GNUNET_TIME_absolute_get_zero()
  82 #define GNUNET_TIME_UNIT_MILLISECONDS GNUNET_TIME_relative_get_unit()
  83 #define GNUNET_TIME_UNIT_SECONDS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MILLISECONDS, 1000)
  84 #define GNUNET_TIME_UNIT_MINUTES GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 60)
  85 #define GNUNET_TIME_UNIT_HOURS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 60)
  86 #define GNUNET_TIME_UNIT_DAYS    GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS,   24)
  87 #define GNUNET_TIME_UNIT_WEEKS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,     7)
  88 #define GNUNET_TIME_UNIT_MONTHS  GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,    30)
  89 #define GNUNET_TIME_UNIT_YEARS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,   365)
  90
  91 /**
  92  * Constant used to specify "forever".  This constant
  93  * will be treated specially in all time operations.
  94  */
  95 #define GNUNET_TIME_UNIT_FOREVER_REL GNUNET_TIME_relative_get_forever ()
  96
  97 /**
  98  * Constant used to specify "forever".  This constant
  99  * will be treated specially in all time operations.
 100  */
 101 #define GNUNET_TIME_UNIT_FOREVER_ABS GNUNET_TIME_absolute_get_forever ()
 102
 103 /**
 104  * Return relative time of 0ms.
 105  */
 106 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_zero (void);
 107
 108 /**
 109  * Return absolute time of 0ms.
 110  */
 111 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get_zero (void);
 112
 113 /**
 114  * Return relative time of 1ms.
 115  */
 116 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_unit (void);
 117
 118 /**
 119  * Return "forever".
 120  */
 121 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_forever (void);
 122
 123 /**
 124  * Return "forever".
 125  */
 126 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get_forever (void);
 127
 128 /**
 129  * Get the current time.
 130  *
 131  * @return the current time
 132  */
 133 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get (void);
 134
 135 /**
 136  * Convert relative time to an absolute time in the
 137  * future.
 138  *
 139  * @return timestamp that is "rel" in the future, or FOREVER if rel==FOREVER (or if we would overflow)
 140  */
 141 struct GNUNET_TIME_Absolute GNUNET_TIME_relative_to_absolute (struct
 142                                                               GNUNET_TIME_Relative
 143                                                               rel);
 144
 145 /**
 146  * Return the minimum of two relative time values.
 147  *
 148  * @return timestamp that is smaller
 149  */
 150 struct GNUNET_TIME_Relative GNUNET_TIME_relative_min (struct
 151                                                       GNUNET_TIME_Relative
 152                                                       t1,
 153                                                       struct
 154                                                       GNUNET_TIME_Relative t2);
 155
 156 /**
 157  * Given a timestamp in the future, how much time
 158  * remains until then?
 159  *
 160  * @return future - now, or 0 if now >= future, or FOREVER if future==FOREVER.
 161  */
 162 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_remaining (struct
 163                                                                 GNUNET_TIME_Absolute
 164                                                                 future);
 165
 166
 167 /**
 168  * Calculate the estimate time of arrival/completion
 169  * for an operation.
 170  *
 171  * @param start when did the operation start?
 172  * @param finished how much has been done?
 173  * @param total how much must be done overall (same unit as for "finished")
 174  * @return remaining duration for the operation,
 175  *        assuming it continues at the same speed
 176  */
 177 struct GNUNET_TIME_Relative GNUNET_TIME_calculate_eta (struct GNUNET_TIME_Absolute start,
 178                                                        uint64_t finished,
 179                                                        uint64_t total);
 180
 181
 182 /**
 183  * Compute the time difference between the given start and end times.
 184  * Use this function instead of actual subtraction to ensure that
 185  * "FOREVER" and overflows are handeled correctly.
 186  *
 187  * @return 0 if start >= end; FOREVER if end==FOREVER; otherwise end - start
 188  */
 189 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_difference (struct
 190                                                                  GNUNET_TIME_Absolute
 191                                                                  start,
 192                                                                  struct
 193                                                                  GNUNET_TIME_Absolute
 194                                                                  end);
 195
 196 /**
 197  * Get the duration of an operation as the
 198  * difference of the current time and the given start time "hence".
 199  *
 200  * @return aborts if hence==FOREVER, 0 if hence > now, otherwise now-hence.
 201  */
 202 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_duration (struct
 203                                                                GNUNET_TIME_Absolute
 204                                                                hence);
 205
 206
 207 /**
 208  * Add a given relative duration to the
 209  * given start time.
 210  *
 211  * @return FOREVER if either argument is FOREVER or on overflow; start+duration otherwise
 212  */
 213 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_add (struct
 214                                                       GNUNET_TIME_Absolute
 215                                                       start,
 216                                                       struct
 217                                                       GNUNET_TIME_Relative
 218                                                       duration);
 219
 220 /**
 221  * Multiply relative time by a given factor.
 222  *
 223  * @return FOREVER if rel=FOREVER or on overflow; otherwise rel*factor
 224  */
 225 struct GNUNET_TIME_Relative GNUNET_TIME_relative_multiply (struct
 226                                                            GNUNET_TIME_Relative
 227                                                            rel,
 228                                                            unsigned int
 229                                                            factor);
 230
 231 /**
 232  * Add relative times together.
 233  *
 234  * @return FOREVER if either argument is FOREVER or on overflow; a1+a2 otherwise
 235  */
 236 struct GNUNET_TIME_Relative GNUNET_TIME_relative_add (struct
 237                                                       GNUNET_TIME_Relative a1,
 238                                                       struct
 239                                                       GNUNET_TIME_Relative
 240                                                       a2);
 241
 242
 243 /**
 244  * Convert relative time to network byte order.
 245  */
 246 struct GNUNET_TIME_RelativeNBO GNUNET_TIME_relative_hton (struct
 247                                                           GNUNET_TIME_Relative
 248                                                           a);
 249
 250 /**
 251  * Convert relative time from network byte order.
 252  */
 253 struct GNUNET_TIME_Relative GNUNET_TIME_relative_ntoh (struct
 254                                                        GNUNET_TIME_RelativeNBO
 255                                                        a);
 256
 257 /**
 258  * Convert relative time to network byte order.
 259  */
 260 struct GNUNET_TIME_AbsoluteNBO GNUNET_TIME_absolute_hton (struct
 261                                                           GNUNET_TIME_Absolute
 262                                                           a);
 263
 264 /**
 265  * Convert relative time from network byte order.
 266  */
 267 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_ntoh (struct
 268                                                        GNUNET_TIME_AbsoluteNBO
 269                                                        a);
 270
 271 #if 0                           /* keep Emacsens' auto-indent happy */
 272 {
 273 #endif
 274 #ifdef __cplusplus
 275 }
 276 #endif
 277
 278 /* ifndef GNUNET_TIME_LIB_H */
 279 #endif
 280 /* end of gnunet_time_lib.h */