include/internal/time.h

   1 /*
   2  * Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #ifndef OSSL_INTERNAL_TIME_H
  11 # define OSSL_INTERNAL_TIME_H
  12 # pragma once
  13
  14 # include <openssl/e_os2.h>     /* uint64_t */
  15 # include "internal/e_os.h"     /* for struct timeval */
  16 # include "internal/safe_math.h"
  17
  18 /*
  19  * Internal type defining a time.
  20  * This should be treated as an opaque structure.
  21  *
  22  * The time datum is Unix's 1970 and at nanosecond precision, this gives
  23  * a range of 584 years roughly.
  24  */
  25 typedef struct {
  26     uint64_t t;     /* Ticks since the epoch */
  27 } OSSL_TIME;
  28
  29 /* The precision of times allows this many values per second */
  30 # define OSSL_TIME_SECOND ((uint64_t)1000000000)
  31
  32 /* One millisecond. */
  33 # define OSSL_TIME_MS     (OSSL_TIME_SECOND / 1000)
  34
  35 /* One microsecond. */
  36 # define OSSL_TIME_US     (OSSL_TIME_MS     / 1000)
  37
  38 /* Convert a tick count into a time */
  39 static ossl_unused ossl_inline OSSL_TIME ossl_ticks2time(uint64_t ticks)
  40 {
  41     OSSL_TIME r;
  42
  43     r.t = ticks;
  44     return r;
  45 }
  46
  47 /* Convert a time to a tick count */
  48 static ossl_unused ossl_inline uint64_t ossl_time2ticks(OSSL_TIME t)
  49 {
  50     return t.t;
  51 }
  52
  53 /* Get current time */
  54 OSSL_TIME ossl_time_now(void);
  55
  56 /* The beginning and end of the time range */
  57 static ossl_unused ossl_inline OSSL_TIME ossl_time_zero(void)
  58 {
  59     return ossl_ticks2time(0);
  60 }
  61
  62 static ossl_unused ossl_inline OSSL_TIME ossl_time_infinite(void)
  63 {
  64     return ossl_ticks2time(~(uint64_t)0);
  65 }
  66
  67
  68 /* Convert time to timeval */
  69 static ossl_unused ossl_inline
  70 void ossl_time_time_to_timeval(OSSL_TIME t, struct timeval *out)
  71 {
  72 #ifdef _WIN32
  73     out->tv_sec = (long int)(t.t / OSSL_TIME_SECOND);
  74 #else
  75     out->tv_sec = (time_t)(t.t / OSSL_TIME_SECOND);
  76 #endif
  77     out->tv_usec = (t.t % OSSL_TIME_SECOND) / (OSSL_TIME_SECOND / 1000000);
  78 }
  79
  80 /* Compare two time values, return -1 if less, 1 if greater and 0 if equal */
  81 static ossl_unused ossl_inline
  82 int ossl_time_compare(OSSL_TIME a, OSSL_TIME b)
  83 {
  84     if (a.t > b.t)
  85         return 1;
  86     if (a.t < b.t)
  87         return -1;
  88     return 0;
  89 }
  90
  91 /*
  92  * Arithmetic operations on times.
  93  * These operations are saturating, in that an overflow or underflow returns
  94  * the largest or smallest value respectively.
  95  */
  96 OSSL_SAFE_MATH_UNSIGNED(time, uint64_t)
  97
  98 static ossl_unused ossl_inline
  99 OSSL_TIME ossl_time_add(OSSL_TIME a, OSSL_TIME b)
 100 {
 101     OSSL_TIME r;
 102     int err = 0;
 103
 104     r.t = safe_add_time(a.t, b.t, &err);
 105     return err ? ossl_time_infinite() : r;
 106 }
 107
 108 static ossl_unused ossl_inline
 109 OSSL_TIME ossl_time_subtract(OSSL_TIME a, OSSL_TIME b)
 110 {
 111     OSSL_TIME r;
 112     int err = 0;
 113
 114     r.t = safe_sub_time(a.t, b.t, &err);
 115     return err ? ossl_time_zero() : r;
 116 }
 117
 118 /* Returns |a - b|. */
 119 static ossl_unused ossl_inline
 120 OSSL_TIME ossl_time_abs_difference(OSSL_TIME a, OSSL_TIME b)
 121 {
 122     return a.t > b.t ? ossl_time_subtract(a, b)
 123                      : ossl_time_subtract(b, a);
 124 }
 125
 126 static ossl_unused ossl_inline
 127 OSSL_TIME ossl_time_multiply(OSSL_TIME a, uint64_t b)
 128 {
 129     OSSL_TIME r;
 130     int err = 0;
 131
 132     r.t = safe_mul_time(a.t, b, &err);
 133     return err ? ossl_time_infinite() : r;
 134 }
 135
 136 static ossl_unused ossl_inline
 137 OSSL_TIME ossl_time_divide(OSSL_TIME a, uint64_t b)
 138 {
 139     OSSL_TIME r;
 140     int err = 0;
 141
 142     r.t = safe_div_time(a.t, b, &err);
 143     return err ? ossl_time_zero() : r;
 144 }
 145
 146 /* Return higher of the two given time values. */
 147 static ossl_unused ossl_inline
 148 OSSL_TIME ossl_time_max(OSSL_TIME a, OSSL_TIME b)
 149 {
 150     return a.t > b.t ? a : b;
 151 }
 152
 153 /* Return the lower of the two given time values. */
 154 static ossl_unused ossl_inline
 155 OSSL_TIME ossl_time_min(OSSL_TIME a, OSSL_TIME b)
 156 {
 157     return a.t < b.t ? a : b;
 158 }
 159
 160 #endif