File: versioncmp.c

package info (click to toggle)
git 1:2.20.1-2+deb10u3
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 45,676 kB
  • sloc: ansic: 210,769; sh: 180,432; perl: 29,102; tcl: 21,663; python: 6,143; makefile: 3,700; sed: 189; php: 120; asm: 98; csh: 45; ruby: 24; lisp: 12
file content (193 lines) | stat: -rw-r--r-- 5,323 bytes parent folder | download | duplicates (7)
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
#include "cache.h"
#include "config.h"
#include "string-list.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

static const struct string_list *prereleases;
static int initialized;

struct suffix_match {
	int conf_pos;
	int start;
	int len;
};

static void find_better_matching_suffix(const char *tagname, const char *suffix,
					int suffix_len, int start, int conf_pos,
					struct suffix_match *match)
{
	/*
	 * A better match either starts earlier or starts at the same offset
	 * but is longer.
	 */
	int end = match->len < suffix_len ? match->start : match->start-1;
	int i;
	for (i = start; i <= end; i++)
		if (starts_with(tagname + i, suffix)) {
			match->conf_pos = conf_pos;
			match->start = i;
			match->len = suffix_len;
			break;
		}
}

/*
 * off is the offset of the first different character in the two strings
 * s1 and s2. If either s1 or s2 contains a prerelease suffix containing
 * that offset or a suffix ends right before that offset, then that
 * string will be forced to be on top.
 *
 * If both s1 and s2 contain a (different) suffix around that position,
 * their order is determined by the order of those two suffixes in the
 * configuration.
 * If any of the strings contains more than one different suffixes around
 * that position, then that string is sorted according to the contained
 * suffix which starts at the earliest offset in that string.
 * If more than one different contained suffixes start at that earliest
 * offset, then that string is sorted according to the longest of those
 * suffixes.
 *
 * Return non-zero if *diff contains the return value for versioncmp()
 */
static int swap_prereleases(const char *s1,
			    const char *s2,
			    int off,
			    int *diff)
{
	int i;
	struct suffix_match match1 = { -1, off, -1 };
	struct suffix_match match2 = { -1, off, -1 };

	for (i = 0; i < prereleases->nr; i++) {
		const char *suffix = prereleases->items[i].string;
		int start, suffix_len = strlen(suffix);
		if (suffix_len < off)
			start = off - suffix_len;
		else
			start = 0;
		find_better_matching_suffix(s1, suffix, suffix_len, start,
					    i, &match1);
		find_better_matching_suffix(s2, suffix, suffix_len, start,
					    i, &match2);
	}
	if (match1.conf_pos == -1 && match2.conf_pos == -1)
		return 0;
	if (match1.conf_pos == match2.conf_pos)
		/* Found the same suffix in both, e.g. "-rc" in "v1.0-rcX"
		 * and "v1.0-rcY": the caller should decide based on "X"
		 * and "Y". */
		return 0;

	if (match1.conf_pos >= 0 && match2.conf_pos >= 0)
		*diff = match1.conf_pos - match2.conf_pos;
	else if (match1.conf_pos >= 0)
		*diff = -1;
	else /* if (match2.conf_pos >= 0) */
		*diff = 1;
	return 1;
}

/*
 * 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);
	}

	if (!initialized) {
		const struct string_list *deprecated_prereleases;
		initialized = 1;
		prereleases = git_config_get_value_multi("versionsort.suffix");
		deprecated_prereleases = git_config_get_value_multi("versionsort.prereleasesuffix");
		if (prereleases) {
			if (deprecated_prereleases)
				warning("ignoring versionsort.prereleasesuffix because versionsort.suffix is set");
		} else
			prereleases = deprecated_prereleases;
	}
	if (prereleases && swap_prereleases(s1, s2, (const char *) p1 - s1 - 1,
					    &diff))
		return diff;

	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;
	}
}