1  /* Copyright (C) 1991-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <libc-pointer-arith.h>
      19  #include <string-fzb.h>
      20  #include <string-fzc.h>
      21  #include <string-fzi.h>
      22  #include <string-shift.h>
      23  #include <string.h>
      24  
      25  #undef __strchrnul
      26  #undef strchrnul
      27  
      28  #ifdef STRCHRNUL
      29  # define __strchrnul STRCHRNUL
      30  #endif
      31  
      32  /* Find the first occurrence of C in S or the final NUL byte.  */
      33  char *
      34  __strchrnul (const char *str, int c_in)
      35  {
      36    /* Align pointer to sizeof op_t.  */
      37    uintptr_t s_int = (uintptr_t) str;
      38    const op_t *word_ptr = (const op_t *) PTR_ALIGN_DOWN (str, sizeof (op_t));
      39  
      40    op_t repeated_c = repeat_bytes (c_in);
      41  
      42    op_t word = *word_ptr;
      43    find_t mask = shift_find (find_zero_eq_all (word, repeated_c), s_int);
      44    if (mask != 0)
      45      return (char *) str + index_first (mask);
      46  
      47    do
      48      word = *++word_ptr;
      49    while (! has_zero_eq (word, repeated_c));
      50  
      51    return (char *) word_ptr + index_first_zero_eq (word, repeated_c);
      52  }
      53  #ifndef STRCHRNUL
      54  libc_hidden_def (__strchrnul)
      55  weak_alias (__strchrnul, strchrnul)
      56  #endif