summaryrefslogtreecommitdiff
path: root/EmbeddedPkg/Library/TimeBaseLib/TimeBaseLib.c
blob: c9048d76596087802655a430d0b892953cc40816 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
/** @file
*
*  Copyright (c) 2016, Hisilicon Limited. All rights reserved.
*  Copyright (c) 2016-2019, Linaro Limited. All rights reserved.
*  Copyright (c) 2021, Ampere Computing LLC. All rights reserved.
*
*  SPDX-License-Identifier: BSD-2-Clause-Patent
*
**/

#include <Uefi/UefiBaseType.h>
#include <Uefi/UefiSpec.h>
#include <Library/DebugLib.h>
#include <Library/TimeBaseLib.h>

/**
  Converts Epoch seconds (elapsed since 1970 JANUARY 01, 00:00:00 UTC) to EFI_TIME.

  @param  EpochSeconds   Epoch seconds.
  @param  Time           The time converted to UEFI format.

**/
VOID
EFIAPI
EpochToEfiTime (
  IN  UINTN     EpochSeconds,
  OUT EFI_TIME  *Time
  )
{
  UINTN         a;
  UINTN         b;
  UINTN         c;
  UINTN         d;
  UINTN         g;
  UINTN         j;
  UINTN         m;
  UINTN         y;
  UINTN         da;
  UINTN         db;
  UINTN         dc;
  UINTN         dg;
  UINTN         hh;
  UINTN         mm;
  UINTN         ss;
  UINTN         J;

  J  = (EpochSeconds / 86400) + 2440588;
  j  = J + 32044;
  g  = j / 146097;
  dg = j % 146097;
  c  = (((dg / 36524) + 1) * 3) / 4;
  dc = dg - (c * 36524);
  b  = dc / 1461;
  db = dc % 1461;
  a  = (((db / 365) + 1) * 3) / 4;
  da = db - (a * 365);
  y  = (g * 400) + (c * 100) + (b * 4) + a;
  m  = (((da * 5) + 308) / 153) - 2;
  d  = da - (((m + 4) * 153) / 5) + 122;

  Time->Year  = (UINT16)(y - 4800 + ((m + 2) / 12));
  Time->Month = ((m + 2) % 12) + 1;
  Time->Day   = (UINT8)(d + 1);

  ss = EpochSeconds % 60;
  a  = (EpochSeconds - ss) / 60;
  mm = a % 60;
  b = (a - mm) / 60;
  hh = b % 24;

  Time->Hour        = (UINT8)hh;
  Time->Minute      = (UINT8)mm;
  Time->Second      = (UINT8)ss;
  Time->Nanosecond  = 0;

}

/**
  Calculate Epoch days.

  @param    Time  The UEFI time to be calculated.

  @return   Number of days.

**/
UINTN
EFIAPI
EfiGetEpochDays (
  IN  EFI_TIME  *Time
  )
{
  UINTN a;
  UINTN y;
  UINTN m;
  UINTN JulianDate;  // Absolute Julian Date representation of the supplied Time
  UINTN EpochDays;   // Number of days elapsed since EPOCH_JULIAN_DAY

  a = (14 - Time->Month) / 12 ;
  y = Time->Year + 4800 - a;
  m = Time->Month + (12*a) - 3;

  JulianDate = Time->Day + ((153*m + 2)/5) + (365*y) + (y/4) - (y/100) + (y/400) - 32045;

  ASSERT (JulianDate >= EPOCH_JULIAN_DATE);
  EpochDays = JulianDate - EPOCH_JULIAN_DATE;

  return EpochDays;
}

/**
  Converts EFI_TIME to Epoch seconds (elapsed since 1970 JANUARY 01, 00:00:00 UTC).

  @param    Time  The UEFI time to be converted.

  @return   Number of seconds.

**/
UINTN
EFIAPI
EfiTimeToEpoch (
  IN  EFI_TIME  *Time
  )
{
  UINTN EpochDays;   // Number of days elapsed since EPOCH_JULIAN_DAY
  UINTN EpochSeconds;

  EpochDays = EfiGetEpochDays (Time);

  EpochSeconds = (EpochDays * SEC_PER_DAY) + ((UINTN)Time->Hour * SEC_PER_HOUR) + (Time->Minute * SEC_PER_MIN) + Time->Second;

  return EpochSeconds;
}

/**
  Get the day of the week from the UEFI time.

  @param    Time  The UEFI time to be calculated.

  @return   The day of the week: Sunday=0, Monday=1, ... Saturday=6

**/
UINTN
EfiTimeToWday (
  IN  EFI_TIME  *Time
  )
{
  UINTN EpochDays;   // Number of days elapsed since EPOCH_JULIAN_DAY

  EpochDays = EfiGetEpochDays (Time);

  // 4=1/1/1970 was a Thursday

  return (EpochDays + 4) % 7;
}

/**
  Check if it is a leap year.

  @param    Time  The UEFI time to be checked.

  @retval   TRUE  It is a leap year.
  @retval   FALSE It is NOT a leap year.

**/
BOOLEAN
EFIAPI
IsLeapYear (
  IN EFI_TIME   *Time
  )
{
  if (Time->Year % 4 == 0) {
    if (Time->Year % 100 == 0) {
      if (Time->Year % 400 == 0) {
        return TRUE;
      } else {
        return FALSE;
      }
    } else {
      return TRUE;
    }
  } else {
    return FALSE;
  }
}

/**
  Check if the day in the UEFI time is valid.

  @param    Time    The UEFI time to be checked.

  @retval   TRUE    Valid.
  @retval   FALSE   Invalid.

**/
BOOLEAN
EFIAPI
IsDayValid (
  IN  EFI_TIME  *Time
  )
{
  STATIC CONST INTN DayOfMonth[12] = { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

  if (Time->Day < 1 ||
      Time->Day > DayOfMonth[Time->Month - 1] ||
      (Time->Month == 2 && (!IsLeapYear (Time) && Time->Day > 28))
     ) {
    return FALSE;
  }

  return TRUE;
}

/**
  Check if the UEFI time is valid.

  @param    Time    The UEFI time to be checked.

  @retval   TRUE    Valid.
  @retval   FALSE   Invalid.

**/
BOOLEAN
EFIAPI
IsTimeValid(
  IN EFI_TIME *Time
  )
{
  // Check the input parameters are within the range specified by UEFI
  if ((Time->Year   < 2000) ||
     (Time->Year   > 2099) ||
     (Time->Month  < 1   ) ||
     (Time->Month  > 12  ) ||
     (!IsDayValid (Time)    ) ||
     (Time->Hour   > 23  ) ||
     (Time->Minute > 59  ) ||
     (Time->Second > 59  ) ||
     (Time->Nanosecond > 999999999) ||
     (!((Time->TimeZone == EFI_UNSPECIFIED_TIMEZONE) || ((Time->TimeZone >= -1440) && (Time->TimeZone <= 1440)))) ||
     (Time->Daylight & (~(EFI_TIME_ADJUST_DAYLIGHT | EFI_TIME_IN_DAYLIGHT)))
  ) {
    return FALSE;
  }

  return TRUE;
}