source: vendor/glibc/2.3.2/string/argz-replace.c

/* String replacement in an argz vector
   Copyright (C) 1997, 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Written by Miles Bader <miles@gnu.ai.mit.edu>

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <stdlib.h>
#include <string.h>
#include <argz.h>

/* Append BUF, of length BUF_LEN to *TO, of length *TO_LEN, reallocating and
   updating *TO & *TO_LEN appropriately.  If an allocation error occurs,
   *TO's old value is freed, and *TO is set to 0.  */
static void
str_append (char **to, size_t *to_len, const char *buf, const size_t buf_len)
{
  size_t new_len = *to_len + buf_len;
  char *new_to = realloc (*to, new_len + 1);

  if (new_to)
    {
      *((char *) __mempcpy (new_to + *to_len, buf, buf_len)) = '\0';
      *to = new_to;
      *to_len = new_len;
    }
  else
    {
      free (*to);
      *to = 0;
    }
}

/* Replace any occurrences of the string STR in ARGZ with WITH, reallocating
   ARGZ as necessary.  If REPLACE_COUNT is non-zero, *REPLACE_COUNT will be
   incremented by number of replacements performed.  */
error_t
__argz_replace (char **argz, size_t *argz_len, const char *str, const char *with,
                unsigned *replace_count)
{
  error_t err = 0;

  if (str && *str)
    {
      char *arg = 0;
      char *src = *argz;
      size_t src_len = *argz_len;
      char *dst = 0;
      size_t dst_len = 0;
      int delayed_copy = 1;     /* True while we've avoided copying anything.  */
      size_t str_len = strlen (str), with_len = strlen (with);

      while (!err && (arg = argz_next (src, src_len, arg)))
        {
          char *match = strstr (arg, str);
          if (match)
            {
              char *from = match + str_len;
              size_t to_len = match - arg;
              char *to = __strndup (arg, to_len);

              while (to && from)
                {
                  str_append (&to, &to_len, with, with_len);
                  if (to)
                    {
                      match = strstr (from, str);
                      if (match)
                        {
                          str_append (&to, &to_len, from, match - from);
                          from = match + str_len;
                        }
                      else
                        {
                          str_append (&to, &to_len, from, strlen (from));
                          from = 0;
                        }
                    }
                }

              if (to)
                {
                  if (delayed_copy)
                    /* We avoided copying SRC to DST until we found a match;
                       now that we've done so, copy everything from the start
                       of SRC.  */
                    {
                      if (arg > src)
                        err = __argz_append (&dst, &dst_len, src, (arg - src));
                      delayed_copy = 0;
                    }
                  if (! err)
                    err = __argz_add (&dst, &dst_len, to);
                  free (to);
                }
              else
                err = ENOMEM;

              if (replace_count)
                (*replace_count)++;
            }
          else if (! delayed_copy)
            err = __argz_add (&dst, &dst_len, arg);
        }

      if (! err)
        {
          if (! delayed_copy)
            /* We never found any instances of str.  */
            {
              if (src)
                free (src);
              *argz = dst;
              *argz_len = dst_len;
            }
        }
      else if (dst_len > 0)
        free (dst);
    }

  return err;
}
weak_alias (__argz_replace, argz_replace)