1/* Compare strings while treating digits characters numerically.
2 Copyright (C) 1997, 2000, 2002, 2004, 2006, 2009-2012 Free Software
3 Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Jean-François Bignolles <bignolle@ecoledoc.ibp.fr>, 1997.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 2.1, or (at your option)
10 any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public License along
18 with this program; if not, see <http://www.gnu.org/licenses/>. */
19
20#if !_LIBC
21# include <config.h>
22#endif
23
24#include <string.h>
25#include <ctype.h>
26
27/* states: S_N: normal, S_I: comparing integral part, S_F: comparing
28 fractional parts, S_Z: idem but with leading Zeroes only */
29#define S_N 0x0
30#define S_I 0x4
31#define S_F 0x8
32#define S_Z 0xC
33
34/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
35#define CMP 2
36#define LEN 3
37
38
39/* ISDIGIT differs from isdigit, as follows:
40 - Its arg may be any int or unsigned int; it need not be an unsigned char
41 or EOF.
42 - It's typically faster.
43 POSIX says that only '0' through '9' are digits. Prefer ISDIGIT to
44 isdigit unless it's important to use the locale's definition
45 of "digit" even when the host does not conform to POSIX. */
46#define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)
47
48#undef __strverscmp
49#undef strverscmp
50
51#ifndef weak_alias
52# define __strverscmp strverscmp
53#endif
54
55/* Compare S1 and S2 as strings holding indices/version numbers,
56 returning less than, equal to or greater than zero if S1 is less than,
57 equal to or greater than S2 (for more info, see the texinfo doc).
58*/
59
60int
61__strverscmp (const char *s1, const char *s2)
62{
63 const unsigned char *p1 = (const unsigned char *) s1;
64 const unsigned char *p2 = (const unsigned char *) s2;
65 unsigned char c1, c2;
66 int state;
67 int diff;
68
69 /* Symbol(s) 0 [1-9] others (padding)
70 Transition (10) 0 (01) d (00) x (11) - */
71 static const unsigned int next_state[] =
72 {
73 /* state x d 0 - */
74 /* S_N */ S_N, S_I, S_Z, S_N,
75 /* S_I */ S_N, S_I, S_I, S_I,
76 /* S_F */ S_N, S_F, S_F, S_F,
77 /* S_Z */ S_N, S_F, S_Z, S_Z
78 };
79
80 static const int result_type[] =
81 {
82 /* state x/x x/d x/0 x/- d/x d/d d/0 d/-
83 0/x 0/d 0/0 0/- -/x -/d -/0 -/- */
84
85 /* S_N */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP,
86 CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
87 /* S_I */ CMP, -1, -1, CMP, 1, LEN, LEN, CMP,
88 1, LEN, LEN, CMP, CMP, CMP, CMP, CMP,
89 /* S_F */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP,
90 CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
91 /* S_Z */ CMP, 1, 1, CMP, -1, CMP, CMP, CMP,
92 -1, CMP, CMP, CMP
93 };
94
95 if (p1 == p2)
96 return 0;
97
98 c1 = *p1++;
99 c2 = *p2++;
100 /* Hint: '0' is a digit too. */
101 state = S_N | ((c1 == '0') + (ISDIGIT (c1) != 0));
102
103 while ((diff = c1 - c2) == 0 && c1 != '\0')
104 {
105 state = next_state[state];
106 c1 = *p1++;
107 c2 = *p2++;
108 state |= (c1 == '0') + (ISDIGIT (c1) != 0);
109 }
110
111 state = result_type[state << 2 | ((c2 == '0') + (ISDIGIT (c2) != 0))];
112
113 switch (state)
114 {
115 case CMP:
116 return diff;
117
118 case LEN:
119 while (ISDIGIT (*p1++))
120 if (!ISDIGIT (*p2++))
121 return 1;
122
123 return ISDIGIT (*p2) ? -1 : diff;
124
125 default:
126 return state;
127 }
128}
129#ifdef weak_alias
130weak_alias (__strverscmp, strverscmp)
131#endif
132