locale/indigits.h

   1 /* Copyright (C) 2000-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.org>, 2000.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <assert.h>
  20 #include <langinfo.h>
  21 #include <string.h>
  22
  23 /* Look up the value of the next multibyte character and return its numerical
  24    value if it is one of the digits known in the locale.  If *DECIDED is
  25    -1 this means it is not yet decided which form it is and we have to
  26    search through all available digits.  Otherwise we know which script
  27    the digits are from.  */
  28 static inline int
  29 indigit_value (const char **s, size_t *len, int *decided)
  30 {
  31   int from_level;
  32   int to_level;
  33   const char *mbdigits[10];
  34   int i;
  35   int n;
  36
  37   if (*decided != -1)
  38     from_level = to_level = *decided;
  39   else
  40     {
  41       from_level = 0;
  42       to_level = _NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_INDIGITS_MB_LEN) - 1;
  43       assert (from_level <= to_level);
  44     }
  45
  46   /* In this round we get the pointer to the digit strings and also perform
  47      the first round of comparisons.  */
  48   for (n = 0; n < 10; ++n)
  49     {
  50       size_t dlen;
  51
  52       /* Get the string for the digits with value N.  */
  53       mbdigits[n] = _NL_CURRENT (LC_CTYPE, _NL_CTYPE_INDIGITS0_MB + n);
  54       dlen = strlen (mbdigits[n]);
  55
  56       if (from_level == 0 && dlen <= *len
  57           && memcmp (*s, mbdigits[n], dlen) == 0)
  58         {
  59           /* Found it.  */
  60           *s += dlen;
  61           *len -= dlen;
  62           if (*decided == -1)
  63             *decided = 0;
  64           return n;
  65         }
  66
  67       /* Advance the pointer to the next string.  */
  68       mbdigits[n] += dlen + 1;
  69     }
  70
  71   /* Now perform the remaining tests.  */
  72   for (i = 1; i <= to_level; ++i)
  73     {
  74       /* Search all ten digits of this level.  */
  75       for (n = 0; n < 10; ++n)
  76         {
  77           size_t dlen = strlen (mbdigits[n]);
  78
  79           if (i >= from_level && dlen <= *len
  80               && memcmp (*s, mbdigits[n], dlen) == 0)
  81             {
  82               /* Found it.  */
  83               *s += dlen;
  84               *len -= dlen;
  85               if (*decided == -1)
  86                 *decided = from_level;
  87               return n;
  88             }
  89
  90           /* Advance the pointer to the next string.  */
  91           mbdigits[n] += dlen + 1;
  92         }
  93     }
  94
  95   /* If we reach this point no matching digit was found.  */
  96   return -1;
  97 }