/* Compatibility symbols for the obsolete <regexp.h> interface.
   Copyright (C) 1996-2025 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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
   <https://www.gnu.org/licenses/>.  */

/* regexp.h now contains only an #error directive, so it cannot be
   used in this file.

   The function that would produce an 'expbuf' to use as the second
   argument to 'step' and 'advance' was defined only in regexp.h,
   as its definition depended on macros defined by the user.  */

#include <stdint.h>
#include <regex.h>
#include <shlib-compat.h>

#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)

/* Define the variables used for the interface.  */
char *loc1;
char *loc2;
compat_symbol (libc, loc1, loc1, GLIBC_2_0);
compat_symbol (libc, loc2, loc2, GLIBC_2_0);

/* Although we do not support the use we define this variable as well.  */
char *locs;
compat_symbol (libc, locs, locs, GLIBC_2_0);


/* Find the next match in STRING.  The compiled regular expression is
   found in the buffer starting at EXPBUF.  `loc1' will return the
   first character matched and `loc2' points to the next unmatched
   character.  */
int
weak_function attribute_compat_text_section
step (const char *string, const char *expbuf)
{
  regmatch_t match;	/* We only need info about the full match.  */

  expbuf += __alignof (regex_t *);
  expbuf -= ((uintptr_t) expbuf) % __alignof__ (regex_t *);

  if (__regexec ((const regex_t *) expbuf, string, 1, &match, REG_NOTEOL)
      == REG_NOMATCH)
    return 0;

  loc1 = (char *) string + match.rm_so;
  loc2 = (char *) string + match.rm_eo;
  return 1;
}
compat_symbol (libc, step, step, GLIBC_2_0);


/* Match the beginning of STRING with the compiled regular expression
   in EXPBUF.  If the match is successful `loc2' will contain the
   position of the first unmatched character.  */
int
weak_function attribute_compat_text_section
advance (const char *string, const char *expbuf)
{
  regmatch_t match;	/* We only need info about the full match.  */

  expbuf += __alignof__ (regex_t *);
  expbuf -= ((uintptr_t) expbuf) % __alignof__ (regex_t *);

  if (__regexec ((const regex_t *) expbuf, string, 1, &match, REG_NOTEOL)
      == REG_NOMATCH
      /* We have to check whether the check is at the beginning of the
	 buffer.  */
      || match.rm_so != 0)
    return 0;

  loc2 = (char *) string + match.rm_eo;
  return 1;
}
compat_symbol (libc, advance, advance, GLIBC_2_0);


#endif /* SHLIB_COMPAT (2.0, 2.23) */
