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
|
/* Compare strings while treating digits characters numerically.
Copyright (C) 1997-2017 Free Software Foundation, Inc.
This file is part of the libiberty library.
Contributed by Jean-François Bignolles <bignolle@ecoledoc.ibp.fr>, 1997.
Libiberty is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Libiberty is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA. */
#include "libiberty.h"
#include "safe-ctype.h"
/*
@deftypefun int strverscmp (const char *@var{s1}, const char *@var{s2})
The @code{strverscmp} function compares the string @var{s1} against
@var{s2}, considering them as holding indices/version numbers. Return
value follows the same conventions as found in the @code{strverscmp}
function. In fact, if @var{s1} and @var{s2} contain no digits,
@code{strverscmp} behaves like @code{strcmp}.
Basically, we compare strings normally (character by character), until
we find a digit in each string - then we enter a special comparison
mode, where each sequence of digits is taken as a whole. If we reach the
end of these two parts without noticing a difference, we return to the
standard comparison mode. There are two types of numeric parts:
"integral" and "fractional" (those begin with a '0'). The types
of the numeric parts affect the way we sort them:
@itemize @bullet
@item
integral/integral: we compare values as you would expect.
@item
fractional/integral: the fractional part is less than the integral one.
Again, no surprise.
@item
fractional/fractional: the things become a bit more complex.
If the common prefix contains only leading zeroes, the longest part is less
than the other one; else the comparison behaves normally.
@end itemize
@smallexample
strverscmp ("no digit", "no digit")
@result{} 0 // @r{same behavior as strcmp.}
strverscmp ("item#99", "item#100")
@result{} <0 // @r{same prefix, but 99 < 100.}
strverscmp ("alpha1", "alpha001")
@result{} >0 // @r{fractional part inferior to integral one.}
strverscmp ("part1_f012", "part1_f01")
@result{} >0 // @r{two fractional parts.}
strverscmp ("foo.009", "foo.0")
@result{} <0 // @r{idem, but with leading zeroes only.}
@end smallexample
This function is especially useful when dealing with filename sorting,
because filenames frequently hold indices/version numbers.
@end deftypefun
*/
/* states: S_N: normal, S_I: comparing integral part, S_F: comparing
fractional parts, S_Z: idem but with leading Zeroes only */
#define S_N 0x0
#define S_I 0x4
#define S_F 0x8
#define S_Z 0xC
/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
#define CMP 2
#define LEN 3
/* 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 Glibc texinfo doc). */
int
strverscmp (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;
int diff;
/* Symbol(s) 0 [1-9] others (padding)
Transition (10) 0 (01) d (00) x (11) - */
static const unsigned int next_state[] =
{
/* state x d 0 - */
/* S_N */ S_N, S_I, S_Z, S_N,
/* S_I */ S_N, S_I, S_I, S_I,
/* S_F */ S_N, S_F, S_F, S_F,
/* S_Z */ S_N, S_F, S_Z, S_Z
};
static const int result_type[] =
{
/* state x/x x/d x/0 x/- d/x d/d d/0 d/-
0/x 0/d 0/0 0/- -/x -/d -/0 -/- */
/* S_N */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP,
CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
/* S_I */ CMP, -1, -1, CMP, +1, LEN, LEN, CMP,
+1, LEN, LEN, CMP, CMP, CMP, CMP, CMP,
/* S_F */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP,
CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
/* S_Z */ CMP, +1, +1, CMP, -1, CMP, CMP, CMP,
-1, CMP, 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 && c1 != '\0')
{
state = next_state[state];
c1 = *p1++;
c2 = *p2++;
state |= (c1 == '0') + (ISDIGIT (c1) != 0);
}
state = result_type[state << 2 | (((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;
}
}
|
