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0683223a MW |
1 | /* -*-c-*- |
2 | * | |
3 | * $Id$ | |
4 | * | |
5 | * Compare version numbers using the Debian algorithm | |
6 | * | |
7 | * (c) 2007 Straylight/Edgeware | |
8 | */ | |
9 | ||
d4efbcd9 | 10 | /*----- Licensing notice --------------------------------------------------* |
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11 | * |
12 | * This file is part of the mLib utilities library. | |
13 | * | |
14 | * mLib is free software; you can redistribute it and/or modify | |
15 | * it under the terms of the GNU Library General Public License as | |
16 | * published by the Free Software Foundation; either version 2 of the | |
17 | * License, or (at your option) any later version. | |
d4efbcd9 | 18 | * |
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19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
22 | * GNU Library General Public License for more details. | |
d4efbcd9 | 23 | * |
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24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with mLib; if not, write to the Free | |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
27 | * MA 02111-1307, USA. | |
28 | */ | |
29 | ||
30 | /*----- Header files ------------------------------------------------------*/ | |
31 | ||
32 | #include <ctype.h> | |
33 | #include <string.h> | |
34 | ||
35 | #include "versioncmp.h" | |
36 | ||
37 | /*----- Main code ---------------------------------------------------------*/ | |
38 | ||
39 | /* --- @versioncmp@ --- * | |
40 | * | |
41 | * Arguments: @const char *va, *vb@ = two version strings | |
42 | * | |
43 | * Returns: Less than, equal to, or greater than zero, according to | |
44 | * whether @va@ is less than, equal to, or greater than @vb@. | |
45 | * | |
46 | * Use: Compares version number strings. | |
47 | * | |
48 | * The algorithm is an extension of the Debian version | |
49 | * comparison algorithm. A version number consists of three | |
50 | * components: | |
51 | * | |
52 | * [EPOCH :] MAIN [- SUB] | |
53 | * | |
54 | * The MAIN part may contain colons or hyphens if there is an | |
55 | * EPOCH or SUB, respectively. Version strings are compared | |
56 | * componentwise: first epochs, then main parts, and finally | |
57 | * subparts. | |
58 | * | |
59 | * The component comparison is done as follows. First, the | |
60 | * initial subsequence of nondigit characters is extracted from | |
61 | * each string, and these are compared lexicographically, using | |
62 | * ASCII ordering, except that letters precede non-letters. If | |
63 | * both are the same, an initial sequence of digits is extracted | |
64 | * from the remaining parts of the version strings, and these | |
65 | * are compared numerically (an empty sequence being considered | |
66 | * to have the value zero). This process is repeated until we | |
67 | * have a winner or until both strings are exhausted. | |
68 | */ | |
69 | ||
70 | struct vinfo { | |
71 | const char *e, *el; | |
72 | const char *m, *ml; | |
73 | const char *s, *sl; | |
74 | }; | |
75 | ||
76 | static int vint(const char **vv, const char *vl) | |
77 | { | |
78 | int n = 0; | |
79 | const char *v = *vv; | |
80 | int ch; | |
81 | ||
82 | while (v < vl) { | |
83 | ch = *v; | |
84 | if (!isdigit((unsigned char)ch)) | |
85 | break; | |
86 | v++; | |
87 | n = n * 10 + (ch - '0'); | |
88 | } | |
89 | *vv = v; | |
90 | return (n); | |
91 | } | |
92 | ||
93 | static const char *vchr(const char **vv, const char *vl) | |
94 | { | |
95 | const char *v = *vv; | |
96 | const char *b = v; | |
97 | int ch; | |
98 | ||
99 | while (v < vl) { | |
100 | ch = *v; | |
101 | if (isdigit((unsigned char)ch)) | |
102 | break; | |
103 | v++; | |
104 | } | |
105 | *vv = v; | |
106 | return (b); | |
107 | } | |
108 | ||
109 | #define CMP(x, y) ((x) < (y) ? -1 : +1) | |
110 | ||
111 | static int vcmp(const char *va, const char *val, | |
112 | const char *vb, const char *vbl) | |
113 | { | |
114 | const char *pa, *pb; | |
115 | int ia, ib; | |
116 | ||
117 | for (;;) { | |
118 | ||
119 | /* --- See if we're done --- */ | |
120 | ||
121 | if (va == val && vb == vbl) | |
122 | return (0); | |
123 | ||
124 | /* --- Compare nondigit portions --- */ | |
125 | ||
126 | pa = vchr(&va, val); pb = vchr(&vb, vbl); | |
127 | for (;;) { | |
3048fcf9 MW |
128 | if (pa == va) ia = 1; |
129 | else if (isalpha((unsigned char)*pa)) ia = 2; | |
130 | else if (*pa == '~') ia = 0; | |
131 | else ia = 3; | |
132 | ||
133 | if (pb == vb) ib = 1; | |
134 | else if (isalpha((unsigned char)*pb)) ib = 2; | |
135 | else if (*pb == '~') ib = 0; | |
136 | else ib = 3; | |
137 | ||
138 | if (ia != ib) return (CMP(ia, ib)); | |
139 | else if (pa == va && pb == vb) break; | |
140 | else if (*pa != *pb) return (CMP(*pa, *pb)); | |
141 | pa++; pb++; | |
0683223a MW |
142 | } |
143 | ||
144 | /* --- Compare digit portions --- */ | |
145 | ||
146 | ia = vint(&va, val); ib = vint(&vb, vbl); | |
3048fcf9 | 147 | if (ia != ib) return (CMP(ia, ib)); |
0683223a MW |
148 | } |
149 | } | |
150 | ||
151 | static void vsplit(const char *v, struct vinfo *vi) | |
152 | { | |
153 | const char *p; | |
154 | size_t n; | |
155 | ||
156 | if ((p = strchr(v, ':')) == 0) | |
157 | vi->e = vi->el = 0; | |
158 | else { | |
159 | vi->e = v; | |
160 | vi->el = p; | |
161 | v = p + 1; | |
162 | } | |
163 | ||
164 | n = strlen(v); | |
165 | if ((p = strrchr(v, '-')) == 0) | |
166 | vi->s = vi->sl = 0; | |
d4efbcd9 | 167 | else { |
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168 | vi->s = p + 1; |
169 | vi->sl = v + n; | |
170 | n = p - v; | |
171 | } | |
172 | ||
173 | vi->m = v; | |
174 | vi->ml = v + n; | |
175 | } | |
176 | ||
177 | int versioncmp(const char *va, const char *vb) | |
178 | { | |
179 | struct vinfo via, vib; | |
180 | int rc; | |
181 | ||
182 | vsplit(va, &via); vsplit(vb, &vib); | |
183 | if ((rc = vcmp(via.e, via.el, vib.e, vib.el)) != 0 || | |
184 | (rc = vcmp(via.m, via.ml, vib.m, vib.ml)) != 0 || | |
185 | (rc = vcmp(via.s, via.sl, vib.s, vib.sl)) != 0) | |
186 | return (rc); | |
187 | return (0); | |
188 | } | |
189 | ||
190 | /*----- That's all, folks -------------------------------------------------*/ |