1  /* Compare strings while treating digits characters numerically.
       2     Copyright (C) 1997-2021 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4     Contributed by Jean-François Bignolles <bignolle@ecoledoc.ibp.fr>, 1997.
       5  
       6     The GNU C Library is free software; you can redistribute it and/or
       7     modify it under the terms of the GNU Lesser General Public
       8     License as published by the Free Software Foundation; either
       9     version 2.1 of the License, or (at your option) any later version.
      10  
      11     The GNU C Library is distributed in the hope that it will be useful,
      12     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14     Lesser General Public License for more details.
      15  
      16     You should have received a copy of the GNU Lesser General Public
      17     License along with the GNU C Library; if not, see
      18     <https://www.gnu.org/licenses/>.  */
      19  
      20  #ifndef _LIBC
      21  # include <libc-config.h>
      22  # define __strverscmp strverscmp
      23  #endif
      24  
      25  #include <stdint.h>
      26  #include <string.h>
      27  #include <ctype.h>
      28  
      29  /* states: S_N: normal, S_I: comparing integral part, S_F: comparing
      30             fractional parts, S_Z: idem but with leading Zeroes only */
      31  #define  S_N    0x0
      32  #define  S_I    0x3
      33  #define  S_F    0x6
      34  #define  S_Z    0x9
      35  
      36  /* result_type: CMP: return diff; LEN: compare using len_diff/diff */
      37  #define  CMP    2
      38  #define  LEN    3
      39  
      40  
      41  /* Compare S1 and S2 as strings holding indices/version numbers,
      42     returning less than, equal to or greater than zero if S1 is less than,
      43     equal to or greater than S2 (for more info, see the texinfo doc).
      44  */
      45  
      46  int
      47  __strverscmp (const char *s1, const char *s2)
      48  {
      49    const unsigned char *p1 = (const unsigned char *) s1;
      50    const unsigned char *p2 = (const unsigned char *) s2;
      51  
      52    /* Symbol(s)    0       [1-9]   others
      53       Transition   (10) 0  (01) d  (00) x   */
      54    static const uint_least8_t next_state[] =
      55    {
      56        /* state    x    d    0  */
      57        /* S_N */  S_N, S_I, S_Z,
      58        /* S_I */  S_N, S_I, S_I,
      59        /* S_F */  S_N, S_F, S_F,
      60        /* S_Z */  S_N, S_F, S_Z
      61    };
      62  
      63    static const int_least8_t result_type[] =
      64    {
      65        /* state   x/x  x/d  x/0  d/x  d/d  d/0  0/x  0/d  0/0  */
      66  
      67        /* S_N */  CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
      68        /* S_I */  CMP, -1,  -1,  +1,  LEN, LEN, +1,  LEN, LEN,
      69        /* S_F */  CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
      70        /* S_Z */  CMP, +1,  +1,  -1,  CMP, CMP, -1,  CMP, CMP
      71    };
      72  
      73    if (p1 == p2)
      74      return 0;
      75  
      76    unsigned char c1 = *p1++;
      77    unsigned char c2 = *p2++;
      78    /* Hint: '0' is a digit too.  */
      79    int state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
      80  
      81    int diff;
      82    while ((diff = c1 - c2) == 0)
      83      {
      84        if (c1 == '\0')
      85  	return diff;
      86  
      87        state = next_state[state];
      88        c1 = *p1++;
      89        c2 = *p2++;
      90        state += (c1 == '0') + (isdigit (c1) != 0);
      91      }
      92  
      93    state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
      94  
      95    switch (state)
      96    {
      97      case CMP:
      98        return diff;
      99  
     100      case LEN:
     101        while (isdigit (*p1++))
     102  	if (!isdigit (*p2++))
     103  	  return 1;
     104  
     105        return isdigit (*p2) ? -1 : diff;
     106  
     107      default:
     108        return state;
     109    }
     110  }
     111  libc_hidden_def (__strverscmp)
     112  weak_alias (__strverscmp, strverscmp)