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   /**
  47    * The actual value.
  48    */
  49   uint64_t value;
  50 };
  51
  52 /**
  53  * Time for relative time used by GNUnet, in milliseconds.
  54  * Always positive, so we can only refer to future time.
  55  */
  56 struct GNUNET_TIME_Relative
  57 {
  58   /**
  59    * The actual value.
  60    */
  61   uint64_t value;
  62 };
  63
  64
  65 /**
  66  * Time for relative time used by GNUnet, in milliseconds and in network byte order.
  67  */
  68 struct GNUNET_TIME_RelativeNBO
  69 {
  70   /**
  71    * The actual value (in network byte order).
  72    */
  73   uint64_t value__ GNUNET_PACKED;
  74 };
  75
  76
  77 /**
  78  * Time for absolute time used by GNUnet, in milliseconds and in network byte order.
  79  */
  80 struct GNUNET_TIME_AbsoluteNBO
  81 {
  82   /**
  83    * The actual value (in network byte order).
  84    */
  85   uint64_t value__ GNUNET_PACKED;
  86 };
  87
  88
  89 /**
  90  * Relative time zero.
  91  */
  92 #define GNUNET_TIME_UNIT_ZERO     GNUNET_TIME_relative_get_zero()
  93
  94 /**
  95  * Absolute time zero.
  96  */
  97 #define GNUNET_TIME_UNIT_ZERO_ABS GNUNET_TIME_absolute_get_zero()
  98
  99 /**
 100  * One millisecond, our basic time unit.
 101  */
 102 #define GNUNET_TIME_UNIT_MILLISECONDS GNUNET_TIME_relative_get_unit()
 103
 104 /**
 105  * One second.
 106  */
 107 #define GNUNET_TIME_UNIT_SECONDS GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MILLISECONDS, 1000)
 108
 109 /**
 110  * One minute.
 111  */
 112 #define GNUNET_TIME_UNIT_MINUTES GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 60)
 113
 114 /**
 115  * One hour.
 116  */
 117 #define GNUNET_TIME_UNIT_HOURS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 60)
 118
 119 /**
 120  * One day.
 121  */
 122 #define GNUNET_TIME_UNIT_DAYS    GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS,   24)
 123
 124 /**
 125  * One week.
 126  */
 127 #define GNUNET_TIME_UNIT_WEEKS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,     7)
 128
 129 /**
 130  * One month (30 days).
 131  */
 132 #define GNUNET_TIME_UNIT_MONTHS  GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,    30)
 133
 134 /**
 135  * One year (365 days).
 136  */
 137 #define GNUNET_TIME_UNIT_YEARS   GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_DAYS,   365)
 138
 139 /**
 140  * Constant used to specify "forever".  This constant
 141  * will be treated specially in all time operations.
 142  */
 143 #define GNUNET_TIME_UNIT_FOREVER_REL GNUNET_TIME_relative_get_forever ()
 144
 145 /**
 146  * Constant used to specify "forever".  This constant
 147  * will be treated specially in all time operations.
 148  */
 149 #define GNUNET_TIME_UNIT_FOREVER_ABS GNUNET_TIME_absolute_get_forever ()
 150
 151 /**
 152  * Return relative time of 0ms.
 153  */
 154 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_zero (void);
 155
 156 /**
 157  * Return absolute time of 0ms.
 158  */
 159 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get_zero (void);
 160
 161 /**
 162  * Return relative time of 1ms.
 163  */
 164 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_unit (void);
 165
 166 /**
 167  * Return "forever".
 168  */
 169 struct GNUNET_TIME_Relative GNUNET_TIME_relative_get_forever (void);
 170
 171 /**
 172  * Return "forever".
 173  */
 174 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get_forever (void);
 175
 176 /**
 177  * Get the current time.
 178  *
 179  * @return the current time
 180  */
 181 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get (void);
 182
 183 /**
 184  * Convert relative time to an absolute time in the
 185  * future.
 186  *
 187  * @param rel relative time to convert
 188  * @return timestamp that is "rel" in the future, or FOREVER if rel==FOREVER (or if we would overflow)
 189  */
 190 struct GNUNET_TIME_Absolute GNUNET_TIME_relative_to_absolute (struct
 191                                                               GNUNET_TIME_Relative
 192                                                               rel);
 193
 194 /**
 195  * Return the minimum of two relative time values.
 196  *
 197  * @param t1 first timestamp
 198  * @param t2 other timestamp
 199  * @return timestamp that is smaller
 200  */
 201 struct GNUNET_TIME_Relative GNUNET_TIME_relative_min (struct
 202                                                       GNUNET_TIME_Relative
 203                                                       t1,
 204                                                       struct
 205                                                       GNUNET_TIME_Relative t2);
 206
 207
 208 /**
 209  * Return the maximum of two relative time values.
 210  *
 211  * @param t1 first timestamp
 212  * @param t2 other timestamp
 213  * @return timestamp that is larger
 214  */
 215 struct GNUNET_TIME_Relative GNUNET_TIME_relative_max (struct
 216                                                       GNUNET_TIME_Relative
 217                                                       t1,
 218                                                       struct
 219                                                       GNUNET_TIME_Relative t2);
 220
 221 /**
 222  * Return the minimum of two absolute time values.
 223  *
 224  * @param t1 first timestamp
 225  * @param t2 other timestamp
 226  * @return timestamp that is smaller
 227  */
 228 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_min (struct
 229                                                       GNUNET_TIME_Absolute
 230                                                       t1,
 231                                                       struct
 232                                                       GNUNET_TIME_Absolute t2);
 233
 234 /**
 235  * Return the maximum of two absolute time values.
 236  *
 237  * @param t1 first timestamp
 238  * @param t2 other timestamp
 239  * @return timestamp that is smaller
 240  */
 241 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_max (struct
 242                                                       GNUNET_TIME_Absolute
 243                                                       t1,
 244                                                       struct
 245                                                       GNUNET_TIME_Absolute t2);
 246
 247 /**
 248  * Given a timestamp in the future, how much time
 249  * remains until then?
 250  *
 251  * @param future some absolute time, typically in the future
 252  * @return future - now, or 0 if now >= future, or FOREVER if future==FOREVER.
 253  */
 254 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_remaining (struct
 255                                                                 GNUNET_TIME_Absolute
 256                                                                 future);
 257
 258
 259 /**
 260  * Calculate the estimate time of arrival/completion
 261  * for an operation.
 262  *
 263  * @param start when did the operation start?
 264  * @param finished how much has been done?
 265  * @param total how much must be done overall (same unit as for "finished")
 266  * @return remaining duration for the operation,
 267  *        assuming it continues at the same speed
 268  */
 269 struct GNUNET_TIME_Relative GNUNET_TIME_calculate_eta (struct GNUNET_TIME_Absolute start,
 270                                                        uint64_t finished,
 271                                                        uint64_t total);
 272
 273
 274 /**
 275  * Compute the time difference between the given start and end times.
 276  * Use this function instead of actual subtraction to ensure that
 277  * "FOREVER" and overflows are handeled correctly.
 278  *
 279  * @param start some absolute time
 280  * @param end some absolute time (typically larger or equal to start)
 281  * @return 0 if start >= end; FOREVER if end==FOREVER; otherwise end - start
 282  */
 283 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_difference (struct
 284                                                                  GNUNET_TIME_Absolute
 285                                                                  start,
 286                                                                  struct
 287                                                                  GNUNET_TIME_Absolute
 288                                                                  end);
 289
 290 /**
 291  * Get the duration of an operation as the
 292  * difference of the current time and the given start time "hence".
 293  *
 294  * @param hence some absolute time, typically in the past
 295  * @return aborts if hence==FOREVER, 0 if hence > now, otherwise now-hence.
 296  */
 297 struct GNUNET_TIME_Relative GNUNET_TIME_absolute_get_duration (struct
 298                                                                GNUNET_TIME_Absolute
 299                                                                hence);
 300
 301
 302 /**
 303  * Add a given relative duration to the
 304  * given start time.
 305  *
 306  * @param start some absolute time
 307  * @param duration some relative time to add
 308  * @return FOREVER if either argument is FOREVER or on overflow; start+duration otherwise
 309  */
 310 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_add (struct
 311                                                       GNUNET_TIME_Absolute
 312                                                       start,
 313                                                       struct
 314                                                       GNUNET_TIME_Relative
 315                                                       duration);
 316
 317
 318 /**
 319  * Subtract a given relative duration from the
 320  * given start time.
 321  *
 322  * @param start some absolute time
 323  * @param duration some relative time to subtract
 324  * @return ZERO if start <= duration, or FOREVER if start time is FOREVER; start-duration otherwise
 325  */
 326 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_subtract (struct
 327                                                            GNUNET_TIME_Absolute
 328                                                            start,
 329                                                            struct
 330                                                            GNUNET_TIME_Relative
 331                                                            duration);
 332
 333 /**
 334  * Multiply relative time by a given factor.
 335  *
 336  * @param rel some duration
 337  * @param factor integer to multiply with
 338  * @return FOREVER if rel=FOREVER or on overflow; otherwise rel*factor
 339  */
 340 struct GNUNET_TIME_Relative GNUNET_TIME_relative_multiply (struct
 341                                                            GNUNET_TIME_Relative
 342                                                            rel,
 343                                                            unsigned int
 344                                                            factor);
 345
 346 /**
 347  * Divide relative time by a given factor.
 348  *
 349  * @param rel some duration
 350  * @param factor integer to divide by
 351  * @return FOREVER if rel=FOREVER or factor==0; otherwise rel/factor
 352  */
 353 struct GNUNET_TIME_Relative GNUNET_TIME_relative_divide (struct
 354                                                          GNUNET_TIME_Relative
 355                                                          rel,
 356                                                          unsigned int
 357                                                          factor);
 358
 359 /**
 360  * Add relative times together.
 361  *
 362  * @param a1 some relative time
 363  * @param a2 some other relative time
 364  * @return FOREVER if either argument is FOREVER or on overflow; a1+a2 otherwise
 365  */
 366 struct GNUNET_TIME_Relative GNUNET_TIME_relative_add (struct
 367                                                       GNUNET_TIME_Relative a1,
 368                                                       struct
 369                                                       GNUNET_TIME_Relative
 370                                                       a2);
 371
 372 /**
 373  * Subtract relative timestamp from the other.
 374  *
 375  * @param a1 first timestamp
 376  * @param a2 second timestamp
 377  * @return ZERO if a2>=a1 (including both FOREVER), FOREVER if a1 is FOREVER, a1-a2 otherwise
 378  */
 379 struct GNUNET_TIME_Relative
 380 GNUNET_TIME_relative_subtract (struct GNUNET_TIME_Relative a1,
 381                                struct GNUNET_TIME_Relative a2);
 382
 383
 384 /**
 385  * Convert relative time to network byte order.
 386  *
 387  * @param a time to convert
 388  * @return converted time value
 389  */
 390 struct GNUNET_TIME_RelativeNBO GNUNET_TIME_relative_hton (struct
 391                                                           GNUNET_TIME_Relative
 392                                                           a);
 393
 394 /**
 395  * Convert relative time from network byte order.
 396  *
 397  * @param a time to convert
 398  * @return converted time value
 399  */
 400 struct GNUNET_TIME_Relative GNUNET_TIME_relative_ntoh (struct
 401                                                        GNUNET_TIME_RelativeNBO
 402                                                        a);
 403
 404 /**
 405  * Convert relative time to network byte order.
 406  *
 407  * @param a time to convert
 408  * @return converted time value
 409  */
 410 struct GNUNET_TIME_AbsoluteNBO GNUNET_TIME_absolute_hton (struct
 411                                                           GNUNET_TIME_Absolute
 412                                                           a);
 413
 414 /**
 415  * Convert relative time from network byte order.
 416  *
 417  * @param a time to convert
 418  * @return converted time value
 419  */
 420 struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_ntoh (struct
 421                                                        GNUNET_TIME_AbsoluteNBO
 422                                                        a);
 423
 424 #if 0                           /* keep Emacsens' auto-indent happy */
 425 {
 426 #endif
 427 #ifdef __cplusplus
 428 }
 429 #endif
 430
 431 /* ifndef GNUNET_TIME_LIB_H */
 432 #endif
 433 /* end of gnunet_time_lib.h */