1  /* Zero byte detection; indexes.  Generic C version.
       2     Copyright (C) 2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       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 _STRING_FZC_H
      20  #define _STRING_FZC_H 1
      21  
      22  #include <endian.h>
      23  #include <string-fza.h>
      24  #include <string-fzi.h>
      25  
      26  
      27  /* Given a word X that is known to contain a zero byte, return the index of
      28     the first such within the word in memory order.  */
      29  static __always_inline unsigned int
      30  index_first_zero (op_t x)
      31  {
      32    if (__BYTE_ORDER == __LITTLE_ENDIAN)
      33      x = find_zero_low (x);
      34    else
      35      x = find_zero_all (x);
      36    return index_first (x);
      37  }
      38  
      39  /* Similarly, but perform the search for byte equality between X1 and X2.  */
      40  static __always_inline unsigned int
      41  index_first_eq (op_t x1, op_t x2)
      42  {
      43    if (__BYTE_ORDER == __LITTLE_ENDIAN)
      44      x1 = find_eq_low (x1, x2);
      45    else
      46      x1 = find_eq_all (x1, x2);
      47    return index_first (x1);
      48  }
      49  
      50  /* Similarly, but perform the search for zero within X1 or equality between
      51     X1 and X2.  */
      52  static __always_inline unsigned int
      53  index_first_zero_eq (op_t x1, op_t x2)
      54  {
      55    if (__BYTE_ORDER == __LITTLE_ENDIAN)
      56      x1 = find_zero_eq_low (x1, x2);
      57    else
      58      x1 = find_zero_eq_all (x1, x2);
      59    return index_first (x1);
      60  }
      61  
      62  /* Similarly, but perform the search for zero within X1 or inequality between
      63     X1 and X2.  */
      64  static __always_inline unsigned int
      65  index_first_zero_ne (op_t x1, op_t x2)
      66  {
      67    return index_first (find_zero_ne_all (x1, x2));
      68  }
      69  
      70  /* Similarly, but search for the last zero within X.  */
      71  static __always_inline unsigned int
      72  index_last_zero (op_t x)
      73  {
      74    if (__BYTE_ORDER == __LITTLE_ENDIAN)
      75      x = find_zero_all (x);
      76    else
      77      x = find_zero_low (x);
      78    return index_last (x);
      79  }
      80  
      81  static __always_inline unsigned int
      82  index_last_eq (op_t x1, op_t x2)
      83  {
      84    return index_last_zero (x1 ^ x2);
      85  }
      86  
      87  #endif /* STRING_FZC_H */