library/weight.h

/* Copyright (C) 1996-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Written by Ulrich Drepper, <drepper@cygnus.com>.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <stddef.h>
#include <stdint.h>

#include "third_party/glibc_locales/common/localeinfo.h"

/* Find index of weight.  */
static int32_t findidx(const int32_t *table, const unsigned char *extra,
                       const int32_t *indirect, const unsigned char **cpp,
                       size_t len) {
  int_fast32_t i = table[*(*cpp)++];
  const unsigned char *cp;
  const unsigned char *usrc;

  if (i >= 0) /* This is an index into the weight table.  Cool.  */
    return i;

  /* Oh well, more than one sequence starting with this byte.
     Search for the correct one.  */
  cp = &extra[-i];
  usrc = *cpp;
  --len;
  while (1) {
    size_t nhere;

    /* The first thing is the index.  */
    i = *((const int32_t *)cp);
    cp += sizeof(int32_t);

    /* Next is the length of the byte sequence.  These are always
       short byte sequences so there is no reason to call any
       function (even if they are inlined).  */
    nhere = *cp++;

    if (i >= 0) {
      /* It is a single character.  If it matches we found our
         index.  Note that at the end of each list there is an
         entry of length zero which represents the single byte
         sequence.  The first (and here only) byte was tested
         already.  */
      size_t cnt;

      for (cnt = 0; cnt < nhere && cnt < len; ++cnt)
        if (cp[cnt] != usrc[cnt]) break;

      if (cnt == nhere) {
        /* Found it.  */
        *cpp += nhere;
        return i;
      }

      /* Up to the next entry.  */
      cp += nhere;
      if (!LOCFILE_ALIGNED_P(1 + nhere))
        cp += LOCFILE_ALIGN - (1 + nhere) % LOCFILE_ALIGN;
    } else {
      /* This is a range of characters.  First decide whether the
         current byte sequence lies in the range.  */
      size_t cnt;
      size_t offset = 0;

      for (cnt = 0; cnt < nhere && cnt < len; ++cnt)
        if (cp[cnt] != usrc[cnt]) break;

      if (cnt != nhere) {
        if (cnt == len || cp[cnt] > usrc[cnt]) {
          /* Cannot be in this range.  */
          cp += 2 * nhere;
          if (!LOCFILE_ALIGNED_P(1 + 2 * nhere))
            cp += (LOCFILE_ALIGN - (1 + 2 * nhere) % LOCFILE_ALIGN);
          continue;
        }

        /* Test against the end of the range.  */
        for (cnt = 0; cnt < nhere; ++cnt)
          if (cp[nhere + cnt] != usrc[cnt]) break;

        if (cnt != nhere && cp[nhere + cnt] < usrc[cnt]) {
          /* Cannot be in this range.  */
          cp += 2 * nhere;
          if (!LOCFILE_ALIGNED_P(1 + 2 * nhere))
            cp += (LOCFILE_ALIGN - (1 + 2 * nhere) % LOCFILE_ALIGN);
          continue;
        }

        /* This range matches the next characters.  Now find
           the offset in the indirect table.  */
        for (cnt = 0; cp[cnt] == usrc[cnt]; ++cnt)
          ;

        do {
          offset <<= 8;
          offset += usrc[cnt] - cp[cnt];
        } while (++cnt < nhere);
      }

      *cpp += nhere;
      return indirect[-i + offset];
    }
  }

  /* NOTREACHED */
  return 0x43219876;
}