Documentation/stash: remove mention of git reset --hard
[git.git] / versioncmp.c
blob80bfd109fa1285a24dbfa8e9aabdfc3b3bd59801
1 #include "cache.h"
2 #include "string-list.h"
4 /*
5 * versioncmp(): copied from string/strverscmp.c in glibc commit
6 * ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
7 * style. The implementation is under LGPL-2.1 and Git relicenses it
8 * to GPLv2.
9 */
12 * states: S_N: normal, S_I: comparing integral part, S_F: comparing
13 * fractionnal parts, S_Z: idem but with leading Zeroes only
15 #define S_N 0x0
16 #define S_I 0x3
17 #define S_F 0x6
18 #define S_Z 0x9
20 /* result_type: CMP: return diff; LEN: compare using len_diff/diff */
21 #define CMP 2
22 #define LEN 3
24 static const struct string_list *prereleases;
25 static int initialized;
28 * p1 and p2 point to the first different character in two strings. If
29 * either p1 or p2 starts with a prerelease suffix, it will be forced
30 * to be on top.
32 * If both p1 and p2 start with (different) suffix, the order is
33 * determined by config file.
35 * Note that we don't have to deal with the situation when both p1 and
36 * p2 start with the same suffix because the common part is already
37 * consumed by the caller.
39 * Return non-zero if *diff contains the return value for versioncmp()
41 static int swap_prereleases(const void *p1_,
42 const void *p2_,
43 int *diff)
45 const char *p1 = p1_;
46 const char *p2 = p2_;
47 int i, i1 = -1, i2 = -1;
49 for (i = 0; i < prereleases->nr; i++) {
50 const char *suffix = prereleases->items[i].string;
51 if (i1 == -1 && starts_with(p1, suffix))
52 i1 = i;
53 if (i2 == -1 && starts_with(p2, suffix))
54 i2 = i;
56 if (i1 == -1 && i2 == -1)
57 return 0;
58 if (i1 >= 0 && i2 >= 0)
59 *diff = i1 - i2;
60 else if (i1 >= 0)
61 *diff = -1;
62 else /* if (i2 >= 0) */
63 *diff = 1;
64 return 1;
68 * Compare S1 and S2 as strings holding indices/version numbers,
69 * returning less than, equal to or greater than zero if S1 is less
70 * than, equal to or greater than S2 (for more info, see the texinfo
71 * doc).
74 int versioncmp(const char *s1, const char *s2)
76 const unsigned char *p1 = (const unsigned char *) s1;
77 const unsigned char *p2 = (const unsigned char *) s2;
78 unsigned char c1, c2;
79 int state, diff;
82 * Symbol(s) 0 [1-9] others
83 * Transition (10) 0 (01) d (00) x
85 static const uint8_t next_state[] = {
86 /* state x d 0 */
87 /* S_N */ S_N, S_I, S_Z,
88 /* S_I */ S_N, S_I, S_I,
89 /* S_F */ S_N, S_F, S_F,
90 /* S_Z */ S_N, S_F, S_Z
93 static const int8_t result_type[] = {
94 /* state x/x x/d x/0 d/x d/d d/0 0/x 0/d 0/0 */
96 /* S_N */ CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
97 /* S_I */ CMP, -1, -1, +1, LEN, LEN, +1, LEN, LEN,
98 /* S_F */ CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
99 /* S_Z */ CMP, +1, +1, -1, CMP, CMP, -1, CMP, CMP
102 if (p1 == p2)
103 return 0;
105 c1 = *p1++;
106 c2 = *p2++;
107 /* Hint: '0' is a digit too. */
108 state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
110 while ((diff = c1 - c2) == 0) {
111 if (c1 == '\0')
112 return diff;
114 state = next_state[state];
115 c1 = *p1++;
116 c2 = *p2++;
117 state += (c1 == '0') + (isdigit (c1) != 0);
120 if (!initialized) {
121 initialized = 1;
122 prereleases = git_config_get_value_multi("versionsort.prereleasesuffix");
124 if (prereleases && swap_prereleases(p1 - 1, p2 - 1, &diff))
125 return diff;
127 state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
129 switch (state) {
130 case CMP:
131 return diff;
133 case LEN:
134 while (isdigit (*p1++))
135 if (!isdigit (*p2++))
136 return 1;
138 return isdigit (*p2) ? -1 : diff;
140 default:
141 return state;