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getdelim.c

/* getdelim.c --- Implementation of replacement getdelim function.
   Copyright (C) 1994, 1996, 1997, 1998, 2001, 2003, 2005 Free
   Software Foundation, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program 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
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.  */

/* Ported from glibc by Simon Josefsson. */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "getdelim.h"

#include <limits.h>
#include <stdlib.h>
#include <errno.h>

#ifndef SIZE_MAX
# define SIZE_MAX ((size_t) -1)
#endif
#ifndef SSIZE_MAX
# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
#endif
#if !HAVE_FLOCKFILE
# undef flockfile
# define flockfile(x) ((void) 0)
#endif
#if !HAVE_FUNLOCKFILE
# undef funlockfile
# define funlockfile(x) ((void) 0)
#endif

/* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
   NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
   NULL), pointing to *N characters of space.  It is realloc'ed as
   necessary.  Returns the number of characters read (not including
   the null terminator), or -1 on error or EOF.  */

ssize_t
getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
{
  ssize_t result;
  size_t cur_len = 0;

  if (lineptr == NULL || n == NULL || fp == NULL)
    {
      errno = EINVAL;
      return -1;
    }

  flockfile (fp);

  if (*lineptr == NULL || *n == 0)
    {
      *n = 120;
      *lineptr = (char *) malloc (*n);
      if (*lineptr == NULL)
      {
        result = -1;
        goto unlock_return;
      }
    }

  for (;;)
    {
      int i;

      i = getc (fp);
      if (i == EOF)
      {
        result = -1;
        break;
      }

      /* Make enough space for len+1 (for final NUL) bytes.  */
      if (cur_len + 1 >= *n)
      {
        size_t needed_max =
          SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
        size_t needed = 2 * *n + 1;   /* Be generous. */
        char *new_lineptr;

        if (needed_max < needed)
          needed = needed_max;
        if (cur_len + 1 >= needed)
          {
            result = -1;
            goto unlock_return;
          }

        new_lineptr = (char *) realloc (*lineptr, needed);
        if (new_lineptr == NULL)
          {
            result = -1;
            goto unlock_return;
          }

        *lineptr = new_lineptr;
        *n = needed;
      }

      (*lineptr)[cur_len] = i;
      cur_len++;

      if (i == delimiter)
      break;
    }
  (*lineptr)[cur_len] = '\0';
  result = cur_len ? cur_len : result;

 unlock_return:
  funlockfile (fp);
  return result;
}

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