1 /*
2 FUNCTION
3 <<strverscmp>>---version string compare
4
5 INDEX
6 strverscmp
7
8 SYNOPSIS
9 #define _GNU_SOURCE
10 #include <string.h>
11 int strverscmp(const char *<[a]>, const char *<[b]>);
12
13 DESCRIPTION
14 <<strverscmp>> compares the string at <[a]> to
15 the string at <[b]> in a version-logical order.
16
17 RETURNS
18
19 If <<*<[a]>>> version-sorts after <<*<[b]>>>, <<strverscmp>> returns
20 a number greater than zero. If the two strings match, <<strverscmp>>
21 returns zero. If <<*<[a]>>> version-sorts before <<*<[b]>>>,
22 <<strverscmp>> returns a number less than zero.
23
24 PORTABILITY
25 <<strverscmp>> is a GNU extension.
26
27 <<strverscmp>> requires no supporting OS subroutines. It uses
28 isdigit() from elsewhere in this library.
29
30 QUICKREF
31 strverscmp
32 */
33
34 /*
35 From musl src/string/strverscmp.c
36
37 Copyright © 2005-2014 Rich Felker, et al.
38
39 Permission is hereby granted, free of charge, to any person obtaining
40 a copy of this software and associated documentation files (the
41 "Software"), to deal in the Software without restriction, including
42 without limitation the rights to use, copy, modify, merge, publish,
43 distribute, sublicense, and/or sell copies of the Software, and to
44 permit persons to whom the Software is furnished to do so, subject to
45 the following conditions:
46
47 The above copyright notice and this permission notice shall be
48 included in all copies or substantial portions of the Software.
49
50 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
51 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
52 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
53 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
54 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
55 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
56 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
57 */
58
59 #define _GNU_SOURCE
60 #include <ctype.h>
61 #include <string.h>
62
strverscmp(const char * l0,const char * r0)63 int strverscmp(const char *l0, const char *r0)
64 {
65 const unsigned char *l = (const void *)l0;
66 const unsigned char *r = (const void *)r0;
67 size_t i, dp, j;
68 int z = 1;
69
70 /* Find maximal matching prefix and track its maximal digit
71 * suffix and whether those digits are all zeros. */
72 for (dp=i=0; l[i]==r[i]; i++) {
73 int c = l[i];
74 if (!c) return 0;
75 if (!isdigit(c)) dp=i+1, z=1;
76 else if (c!='0') z=0;
77 }
78
79 if (l[dp]!='0' && r[dp]!='0') {
80 /* If we're not looking at a digit sequence that began
81 * with a zero, longest digit string is greater. */
82 for (j=i; isdigit(l[j]); j++)
83 if (!isdigit(r[j])) return 1;
84 if (isdigit(r[j])) return -1;
85 } else if (z && dp<i && (isdigit(l[i]) || isdigit(r[i]))) {
86 /* Otherwise, if common prefix of digit sequence is
87 * all zeros, digits order less than non-digits. */
88 return (unsigned char)(l[i]-'0') - (unsigned char)(r[i]-'0');
89 }
90
91 return l[i] - r[i];
92 }
93
