lib/strutil/strverscmp.c

   1 /*
   2    Compare strings while treating digits characters numerically.
   3
   4    Copyright (C) 1997-2016
   5    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 /*** global variables ****************************************************************************/
  36
  37 /*** file scope macro definitions ****************************************************************/
  38
  39 #ifndef HAVE_STRVERSCMP
  40
  41 /* states: S_N: normal, S_I: comparing integral part, S_F: comparing
  42    fractionnal parts, S_Z: idem but with leading Zeroes only */
  43 #define  S_N    0x0
  44 #define  S_I    0x4
  45 #define  S_F    0x8
  46 #define  S_Z    0xC
  47
  48 /* result_type: CMP: return diff; LEN: compare using len_diff/diff */
  49 #define  CMP    2
  50 #define  LEN    3
  51
  52 #endif /* HAVE_STRVERSCMP */
  53
  54 /*** file scope type declarations ****************************************************************/
  55
  56 /*** file scope variables ************************************************************************/
  57
  58 /* --------------------------------------------------------------------------------------------- */
  59 /*** file scope functions ************************************************************************/
  60 /* --------------------------------------------------------------------------------------------- */
  61
  62 /* --------------------------------------------------------------------------------------------- */
  63 /*** public functions ****************************************************************************/
  64 /* --------------------------------------------------------------------------------------------- */
  65 /* Compare S1 and S2 as strings holding indices/version numbers,
  66    returning less than, equal to or greater than zero if S1 is less than,
  67    equal to or greater than S2 (for more info, see the texinfo doc).
  68  */
  69 int
  70 str_verscmp (const char *s1, const char *s2)
  71 {
  72 #ifdef HAVE_STRVERSCMP
  73     return strverscmp (s1, s2);
  74
  75 #else /* HAVE_STRVERSCMP */
  76     unsigned char *p1 = (unsigned char *) s1;
  77     unsigned char *p2 = (unsigned char *) s2;
  78     unsigned char c1, c2;
  79     int state;
  80     int diff;
  81
  82     /* Symbol(s)    0       [1-9]   others  (padding)
  83        Transition   (10) 0  (01) d  (00) x  (11) -   */
  84     static const unsigned int next_state[] = {
  85         /* state    x    d    0    - */
  86         /* S_N */ S_N, S_I, S_Z, S_N,
  87         /* S_I */ S_N, S_I, S_I, S_I,
  88         /* S_F */ S_N, S_F, S_F, S_F,
  89         /* S_Z */ S_N, S_F, S_Z, S_Z
  90     };
  91
  92     static const int result_type[] = {
  93         /* state   x/x  x/d  x/0  x/-  d/x  d/d  d/0  d/-
  94            0/x  0/d  0/0  0/-  -/x  -/d  -/0  -/- */
  95
  96         /* S_N */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP,
  97         CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
  98         /* S_I */ CMP, -1, -1, CMP, +1, LEN, LEN, CMP,
  99         +1, LEN, LEN, CMP, CMP, CMP, CMP, CMP,
 100         /* S_F */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP,
 101         CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
 102         /* S_Z */ CMP, +1, +1, CMP, -1, CMP, CMP, CMP,
 103         -1, CMP, CMP, CMP
 104     };
 105
 106     if (p1 == p2)
 107         return 0;
 108
 109     c1 = *p1++;
 110     c2 = *p2++;
 111     /* Hint: '0' is a digit too.  */
 112     state = S_N | ((c1 == '0') + (isdigit (c1) != 0));
 113
 114     while ((diff = c1 - c2) == 0 && c1 != '\0')
 115     {
 116         state = next_state[state];
 117         c1 = *p1++;
 118         c2 = *p2++;
 119         state |= (c1 == '0') + (isdigit (c1) != 0);
 120     }
 121
 122     state = result_type[state << 2 | (((c2 == '0') + (isdigit (c2) != 0)))];
 123
 124     switch (state)
 125     {
 126     case CMP:
 127         return diff;
 128
 129     case LEN:
 130         while (isdigit (*p1++))
 131             if (!isdigit (*p2++))
 132                 return 1;
 133
 134         return isdigit (*p2) ? -1 : diff;
 135
 136     default:
 137         return state;
 138     }
 139 #endif /* HAVE_STRVERSCMP */
 140 }
 141
 142 /* --------------------------------------------------------------------------------------------- */