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
|
/**
* @file arith.c
* @date Tue Jul 20 16:12:51 2010
*
* @brief Time format conversion routines and additional math functions.
*
*
*/
#include "ptpd.h"
/* from annex C of the spec */
UInteger32
crc_algorithm(Octet * buf, Integer16 length)
{
Integer16 i;
UInteger8 data;
UInteger32 polynomial = 0xedb88320, crc = 0xffffffff;
while (length-- > 0) {
data = *(UInteger8 *) (buf++);
for (i = 0; i < 8; i++) {
if ((crc ^ data) & 1) {
crc = (crc >> 1);
crc ^= polynomial;
} else {
crc = (crc >> 1);
}
data >>= 1;
}
}
return crc ^ 0xffffffff;
}
UInteger32
sum(Octet * buf, Integer16 length)
{
UInteger32 sum = 0;
while (length-- > 0)
sum += *(UInteger8 *) (buf++);
return sum;
}
void
fromInternalTime(TimeInternal * internal, TimeRepresentation * external, Boolean halfEpoch)
{
external->seconds = labs(internal->seconds) + halfEpoch * INT_MAX;
if (internal->seconds < 0 || internal->nanoseconds < 0) {
external->nanoseconds = labs(internal->nanoseconds) | ~INT_MAX;
} else {
external->nanoseconds = labs(internal->nanoseconds);
}
DBGV("fromInternalTime: %10ds %11dns -> %10us %11dns\n",
internal->seconds, internal->nanoseconds,
external->seconds, external->nanoseconds);
}
void
toInternalTime(TimeInternal * internal, TimeRepresentation * external, Boolean * halfEpoch)
{
*halfEpoch = external->seconds / INT_MAX;
if (external->nanoseconds & ~INT_MAX) {
internal->seconds = -(external->seconds % INT_MAX);
internal->nanoseconds = -(external->nanoseconds & INT_MAX);
} else {
internal->seconds = external->seconds % INT_MAX;
internal->nanoseconds = external->nanoseconds;
}
DBGV("toInternalTime: %10ds %11dns <- %10us %11dns\n",
internal->seconds, internal->nanoseconds,
external->seconds, external->nanoseconds);
}
void
normalizeTime(TimeInternal * r)
{
r->seconds += r->nanoseconds / 1000000000;
r->nanoseconds -= r->nanoseconds / 1000000000 * 1000000000;
if (r->seconds > 0 && r->nanoseconds < 0) {
r->seconds -= 1;
r->nanoseconds += 1000000000;
} else if (r->seconds < 0 && r->nanoseconds > 0) {
r->seconds += 1;
r->nanoseconds -= 1000000000;
}
}
void
addTime(TimeInternal * r, TimeInternal * x, TimeInternal * y)
{
r->seconds = x->seconds + y->seconds;
r->nanoseconds = x->nanoseconds + y->nanoseconds;
normalizeTime(r);
}
void
subTime(TimeInternal * r, TimeInternal * x, TimeInternal * y)
{
r->seconds = x->seconds - y->seconds;
r->nanoseconds = x->nanoseconds - y->nanoseconds;
normalizeTime(r);
}
|
