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
|
#include "cache.h"
/*
* versioncmp(): copied from string/strverscmp.c in glibc commit
* ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
* style. The implementation is under LGPL-2.1 and Git relicenses it
* to GPLv2.
*/
/*
* states: S_N: normal, S_I: comparing integral part, S_F: comparing
* fractionnal parts, S_Z: idem but with leading Zeroes only
*/
#define S_N 0x0
#define S_I 0x3
#define S_F 0x6
#define S_Z 0x9
/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
#define CMP 2
#define LEN 3
/*
* Compare S1 and S2 as strings holding indices/version numbers,
* returning less than, equal to or greater than zero if S1 is less
* than, equal to or greater than S2 (for more info, see the texinfo
* doc).
*/
int versioncmp(const char *s1, const char *s2)
{
const unsigned char *p1 = (const unsigned char *) s1;
const unsigned char *p2 = (const unsigned char *) s2;
unsigned char c1, c2;
int state, diff;
/*
* Symbol(s) 0 [1-9] others
* Transition (10) 0 (01) d (00) x
*/
static const uint8_t next_state[] = {
/* state x d 0 */
/* S_N */ S_N, S_I, S_Z,
/* S_I */ S_N, S_I, S_I,
/* S_F */ S_N, S_F, S_F,
/* S_Z */ S_N, S_F, S_Z
};
static const int8_t result_type[] = {
/* state x/x x/d x/0 d/x d/d d/0 0/x 0/d 0/0 */
/* S_N */ CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
/* S_I */ CMP, -1, -1, +1, LEN, LEN, +1, LEN, LEN,
/* S_F */ CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
/* S_Z */ CMP, +1, +1, -1, CMP, CMP, -1, CMP, CMP
};
if (p1 == p2)
return 0;
c1 = *p1++;
c2 = *p2++;
/* Hint: '0' is a digit too. */
state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
while ((diff = c1 - c2) == 0) {
if (c1 == '\0')
return diff;
state = next_state[state];
c1 = *p1++;
c2 = *p2++;
state += (c1 == '0') + (isdigit (c1) != 0);
}
state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
switch (state) {
case CMP:
return diff;
case LEN:
while (isdigit (*p1++))
if (!isdigit (*p2++))
return 1;
return isdigit (*p2) ? -1 : diff;
default:
return state;
}
}
|
