locale/weightwc.h

   1 /* Copyright (C) 1996-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Written by Ulrich Drepper, <drepper@cygnus.com>.
   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    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _WEIGHTWC_H_
  20 #define _WEIGHTWC_H_    1
  21
  22 #include <libc-diag.h>
  23
  24 /* Find index of weight.  */
  25 static inline int32_t __attribute__ ((always_inline))
  26 findidx (const int32_t *table,
  27          const int32_t *indirect,
  28          const wint_t *extra,
  29          const wint_t **cpp, size_t len)
  30 {
  31   wint_t ch = *(*cpp)++;
  32   int32_t i = __collidx_table_lookup ((const char *) table, ch);
  33
  34   if (i >= 0)
  35     /* This is an index into the weight table.  Cool.  */
  36     return i;
  37
  38   /* Oh well, more than one sequence starting with this byte.
  39      Search for the correct one.  */
  40   const int32_t *cp = (const int32_t *) &extra[-i];
  41   --len;
  42   while (1)
  43     {
  44       size_t nhere;
  45       const int32_t *usrc = (const int32_t *) *cpp;
  46
  47       /* The first thing is the index.  */
  48       i = *cp++;
  49
  50       /* Next is the length of the byte sequence.  These are always
  51          short byte sequences so there is no reason to call any
  52          function (even if they are inlined).  */
  53       nhere = *cp++;
  54
  55       if (i >= 0)
  56         {
  57           /* It is a single character.  If it matches we found our
  58              index.  Note that at the end of each list there is an
  59              entry of length zero which represents the single byte
  60              sequence.  The first (and here only) byte was tested
  61              already.  */
  62           size_t cnt;
  63
  64           /* With GCC 5.3 when compiling with -Os the compiler warns
  65              that seq2.back_us, which becomes usrc, might be used
  66              uninitialized.  This can't be true because we pass a length
  67              of -1 for len at the same time which means that this loop
  68              never executes.  */
  69           DIAG_PUSH_NEEDS_COMMENT;
  70           DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
  71           for (cnt = 0; cnt < nhere && cnt < len; ++cnt)
  72             if (cp[cnt] != usrc[cnt])
  73               break;
  74           DIAG_POP_NEEDS_COMMENT;
  75
  76           if (cnt == nhere)
  77             {
  78               /* Found it.  */
  79               *cpp += nhere;
  80               return i;
  81             }
  82
  83           /* Up to the next entry.  */
  84           cp += nhere;
  85         }
  86       else
  87         {
  88           /* This is a range of characters.  First decide whether the
  89              current byte sequence lies in the range.  */
  90           size_t cnt;
  91           size_t offset;
  92
  93           /* With GCC 7 when compiling with -Os the compiler warns
  94              that seq1.back_us and seq2.back_us, which become usrc,
  95              might be used uninitialized.  This is impossible for the
  96              same reason as described above.  */
  97           DIAG_PUSH_NEEDS_COMMENT;
  98           DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
  99           for (cnt = 0; cnt < nhere - 1 && cnt < len; ++cnt)
 100             if (cp[cnt] != usrc[cnt])
 101               break;
 102           DIAG_POP_NEEDS_COMMENT;
 103
 104           if (cnt < nhere - 1)
 105             {
 106               cp += 2 * nhere;
 107               continue;
 108             }
 109
 110           if (cp[nhere - 1] > usrc[nhere -1])
 111             {
 112               cp += 2 * nhere;
 113               continue;
 114             }
 115
 116           if (cp[2 * nhere - 1] < usrc[nhere -1])
 117             {
 118               cp += 2 * nhere;
 119               continue;
 120             }
 121
 122           /* This range matches the next characters.  Now find
 123              the offset in the indirect table.  */
 124           offset = usrc[nhere - 1] - cp[nhere - 1];
 125           *cpp += nhere;
 126
 127           return indirect[-i + offset];
 128         }
 129     }
 130
 131   /* NOTREACHED */
 132   return 0x43219876;
 133 }
 134
 135 #endif  /* weightwc.h */