lib/strutil/strverscmp.c

   1 /*
   2    Compare strings while treating digits characters numerically.
   3
   4    Copyright (C) 1997, 2002, 2011
   5    The Free Software Foundation, Inc.
   6
   7    This file is part of the GNU C Library.
   8    Contributed by Jean-Fran�ois Bignolles <bignolle ecoledoc ibp fr>, 1997.
   9
  10    This file is part of the Midnight Commander.
  11
  12    The Midnight Commander is free software: you can redistribute it
  13    and/or modify it under the terms of the GNU General Public License as
  14    published by the Free Software Foundation, either version 3 of the License,
  15    or (at your option) any later version.
  16
  17    The Midnight Commander is distributed in the hope that it will be useful,
  18    but WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20    GNU General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24  */
  25
  26 #include <config.h>
  27
  28 #include <ctype.h>
  29 #ifdef HAVE_STRVERSCMP
  30 #include <string.h>
  31 #endif /* HAVE_STRVERSCMP */
  32
  33 #include "lib/strutil.h"
  34
  35 /* states: S_N: normal, S_I: comparing integral part, S_F: comparing
  36    fractionnal parts, S_Z: idem but with leading Zeroes only */
  37 #define  S_N    0x0
  38 #define  S_I    0x4
  39 #define  S_F    0x8
  40 #define  S_Z    0xC
  41
  42 /* result_type: CMP: return diff; LEN: compare using len_diff/diff */
  43 #define  CMP    2
  44 #define  LEN    3
  45
  46
  47 /* Compare S1 and S2 as strings holding indices/version numbers,
  48    returning less than, equal to or greater than zero if S1 is less than,
  49    equal to or greater than S2 (for more info, see the texinfo doc).
  50  */
  51
  52 int
  53 str_verscmp (const char *s1, const char *s2)
  54 {
  55 #ifdef HAVE_STRVERSCMP
  56     return strverscmp (s1, s2);
  57 #else /* HAVE_STRVERSCMP */
  58     unsigned char *p1 = (unsigned char *) s1;
  59     unsigned char *p2 = (unsigned char *) s2;
  60     unsigned char c1, c2;
  61     int state;
  62     int diff;
  63
  64     /* Symbol(s)    0       [1-9]   others  (padding)
  65        Transition   (10) 0  (01) d  (00) x  (11) -   */
  66     static const unsigned int next_state[] = {
  67         /* state    x    d    0    - */
  68         /* S_N */ S_N, S_I, S_Z, S_N,
  69         /* S_I */ S_N, S_I, S_I, S_I,
  70         /* S_F */ S_N, S_F, S_F, S_F,
  71         /* S_Z */ S_N, S_F, S_Z, S_Z
  72     };
  73
  74     static const int result_type[] = {
  75         /* state   x/x  x/d  x/0  x/-  d/x  d/d  d/0  d/-
  76            0/x  0/d  0/0  0/-  -/x  -/d  -/0  -/- */
  77
  78         /* S_N */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP,
  79         CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
  80         /* S_I */ CMP, -1, -1, CMP, +1, LEN, LEN, CMP,
  81         +1, LEN, LEN, CMP, CMP, CMP, CMP, CMP,
  82         /* S_F */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP,
  83         CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
  84         /* S_Z */ CMP, +1, +1, CMP, -1, CMP, CMP, CMP,
  85         -1, CMP, CMP, CMP
  86     };
  87
  88     if (p1 == p2)
  89         return 0;
  90
  91     c1 = *p1++;
  92     c2 = *p2++;
  93     /* Hint: '0' is a digit too.  */
  94     state = S_N | ((c1 == '0') + (isdigit (c1) != 0));
  95
  96     while ((diff = c1 - c2) == 0 && c1 != '\0')
  97     {
  98         state = next_state[state];
  99         c1 = *p1++;
 100         c2 = *p2++;
 101         state |= (c1 == '0') + (isdigit (c1) != 0);
 102     }
 103
 104     state = result_type[state << 2 | (((c2 == '0') + (isdigit (c2) != 0)))];
 105
 106     switch (state)
 107     {
 108     case CMP:
 109         return diff;
 110
 111     case LEN:
 112         while (isdigit (*p1++))
 113             if (!isdigit (*p2++))
 114                 return 1;
 115
 116         return isdigit (*p2) ? -1 : diff;
 117
 118     default:
 119         return state;
 120     }
 121 #endif /* HAVE_STRVERSCMP */
 122
 123 }