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 General Public License as published by
9   the Free Software Foundation; either version 3, 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 General Public License for more details.
16
17   You should have received a copy of the GNU 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