/* getndelim2 - Read n characters or less from a stream, stopping at one of up
   to two specified delimiters.

   Copyright (C) 1993, 1996, 1997, 1998, 2000, 2003 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Originally written by Jan Brittenson, bson@gnu.ai.mit.edu.  */

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

/* Specification.  */
#include "getndelim2.h"

#include <stdlib.h>

#include "unlocked-io.h"

/* Always add at least this many bytes when extending the buffer.  */
#define MIN_CHUNK 64

ssize_t
getndelim2 (char **lineptr, size_t *linesize, size_t offset, size_t limit,
            int delim1, int delim2, FILE *stream)
{
  size_t nbytes_avail;		/* Allocated but unused chars in *LINEPTR.  */
  char *read_pos;		/* Where we're reading into *LINEPTR. */

  if (!lineptr || !linesize || !stream)
    return -1;

  if (!*lineptr)
    {
      *linesize = MIN_CHUNK;
      *lineptr = malloc (*linesize);
      if (!*lineptr)
	return -1;
    }

  if (*linesize < offset)
    return -1;

  nbytes_avail = *linesize - offset;
  read_pos = *lineptr + offset;

  for (;;)
    {
      /* Here always *lineptr + *linesize == read_pos + nbytes_avail.  */
      register int c;

      if (limit == 0)
	break;

      c = getc (stream);

      if (limit != GETNDELIM_NO_LIMIT)
	limit--;

      /* We always want at least one char left in the buffer, since we
	 always (unless we get an error while reading the first char)
	 NUL-terminate the line buffer.  */

      if (nbytes_avail < 2)
	{
	  if (*linesize > MIN_CHUNK)
	    *linesize *= 2;
	  else
	    *linesize += MIN_CHUNK;

	  nbytes_avail = *linesize + *lineptr - read_pos;
	  *lineptr = realloc (*lineptr, *linesize);
	  if (!*lineptr)
	    return -1;
	  read_pos = *linesize - nbytes_avail + *lineptr;
	}

      if (c == EOF)
	{
	  /* Return partial line, if any.  */
	  if (read_pos == *lineptr)
	    return -1;
	  else
	    break;
	}

      *read_pos++ = c;
      nbytes_avail--;

      if (c == delim1 || (delim2 && c == delim2))
	/* Return the line.  */
	break;
    }

  /* Done - NUL terminate and return the number of chars read.
     At this point we know that nbytes_avail >= 1.  */
  *read_pos = '\0';

  return read_pos - (*lineptr + offset);
}