lib/strutil/strverscmp.c

   1 /*
   2    Compare strings while treating digits characters numerically.
   3
   4    Copyright (C) 1997-2019
   5    Free Software Foundation, Inc.
   6
   7    This file is part of the GNU C Library.
   8    Contributed by Jean-François Bignolles <bignolle@ecoledoc.ibp.fr>, 1997.
   9
  10    The GNU C Library is free software; you can redistribute it and/or
  11    modify it under the terms of the GNU Lesser General Public
  12    License as published by the Free Software Foundation; either
  13    version 2.1 of the License, or (at your option) any later version.
  14
  15    The GNU C Library is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18    Lesser General Public License for more details.
  19
  20    You should have received a copy of the GNU Lesser General Public
  21    License along with the GNU C Library; if not, see
  22    <https://www.gnu.org/licenses/>.
  23
  24    This file is part of the Midnight Commander.
  25
  26    The Midnight Commander is free software: you can redistribute it
  27    and/or modify it under the terms of the GNU General Public License as
  28    published by the Free Software Foundation, either version 3 of the License,
  29    or (at your option) any later version.
  30
  31    The Midnight Commander is distributed in the hope that it will be useful,
  32    but WITHOUT ANY WARRANTY; without even the implied warranty of
  33    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  34    GNU General Public License for more details.
  35
  36    You should have received a copy of the GNU General Public License
  37    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  38  */
  39
  40 #include <config.h>
  41
  42 #include <ctype.h>
  43 #ifdef HAVE_STRVERSCMP
  44 #include <string.h>
  45 #endif /* HAVE_STRVERSCMP */
  46
  47 #include "lib/strutil.h"
  48
  49 /*** global variables ****************************************************************************/
  50
  51 /*** file scope macro definitions ****************************************************************/
  52
  53 #ifndef HAVE_STRVERSCMP
  54
  55 /* states: S_N: normal, S_I: comparing integral part, S_F: comparing
  56    fractional parts, S_Z: idem but with leading Zeroes only */
  57 #define  S_N    0x0
  58 #define  S_I    0x3
  59 #define  S_F    0x6
  60 #define  S_Z    0x9
  61
  62 /* result_type: CMP: return diff; LEN: compare using len_diff/diff */
  63 #define  CMP    2
  64 #define  LEN    3
  65
  66 #endif /* HAVE_STRVERSCMP */
  67
  68 /*** file scope type declarations ****************************************************************/
  69
  70 /*** file scope variables ************************************************************************/
  71
  72 /* --------------------------------------------------------------------------------------------- */
  73 /*** file scope functions ************************************************************************/
  74 /* --------------------------------------------------------------------------------------------- */
  75
  76 /* --------------------------------------------------------------------------------------------- */
  77 /*** public functions ****************************************************************************/
  78 /* --------------------------------------------------------------------------------------------- */
  79 /* Compare S1 and S2 as strings holding indices/version numbers,
  80    returning less than, equal to or greater than zero if S1 is less than,
  81    equal to or greater than S2 (for more info, see the texinfo doc).
  82  */
  83 int
  84 str_verscmp (const char *s1, const char *s2)
  85 {
  86 #ifdef HAVE_STRVERSCMP
  87     return strverscmp (s1, s2);
  88
  89 #else /* HAVE_STRVERSCMP */
  90     const unsigned char *p1 = (const unsigned char *) s1;
  91     const unsigned char *p2 = (const unsigned char *) s2;
  92     unsigned char c1, c2;
  93     int state;
  94     int diff;
  95
  96     /* *INDENT-OFF* */
  97     /* Symbol(s)    0       [1-9]   others
  98        Transition   (10) 0  (01) d  (00) x   */
  99     static const unsigned char next_state[] =
 100     {
 101         /* state    x    d    0  */
 102         /* S_N */ S_N, S_I, S_Z,
 103         /* S_I */ S_N, S_I, S_I,
 104         /* S_F */ S_N, S_F, S_F,
 105         /* S_Z */ S_N, S_F, S_Z
 106     };
 107
 108     static const signed char result_type[] =
 109     {
 110         /* state  x/x  x/d  x/0  d/x  d/d  d/0  0/x  0/d  0/0  */
 111
 112         /* S_N */ CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
 113         /* S_I */ CMP,  -1,  -1,  +1, LEN, LEN,  +1, LEN, LEN,
 114         /* S_F */ CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
 115         /* S_Z */ CMP,  +1,  +1,  -1, CMP, CMP,  -1, CMP, CMP
 116     };
 117     /* *INDENT-ON* */
 118
 119     if (p1 == p2)
 120         return 0;
 121
 122     c1 = *p1++;
 123     c2 = *p2++;
 124     /* Hint: '0' is a digit too.  */
 125     state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
 126
 127     while ((diff = c1 - c2) == 0)
 128     {
 129         if (c1 == '\0')
 130             return diff;
 131
 132         state = next_state[state];
 133         c1 = *p1++;
 134         c2 = *p2++;
 135         state += (c1 == '0') + (isdigit (c1) != 0);
 136     }
 137
 138     state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
 139
 140     switch (state)
 141     {
 142     case CMP:
 143         return diff;
 144
 145     case LEN:
 146         while (isdigit (*p1++))
 147             if (!isdigit (*p2++))
 148                 return 1;
 149
 150         return isdigit (*p2) ? -1 : diff;
 151
 152     default:
 153         return state;
 154     }
 155 #endif /* HAVE_STRVERSCMP */
 156 }
 157
 158 /* --------------------------------------------------------------------------------------------- */