/*
 * Buffering to output and input. 
 * Copyright (C) 1998 Kunihiro Ishiguro
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra 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.
 *
 * GNU Zebra 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 GNU Zebra; see the file COPYING.  If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#ifndef _ZEBRA_BUFFER_H
#define _ZEBRA_BUFFER_H

/* Buffer master. */
struct buffer
{
  /* Data list. */
  struct buffer_data *head;
  struct buffer_data *tail;
  
  /* XXX: These unsigned longs should be size_t's */
  /* Current allocated data. */
  unsigned long alloc;

  /* Size of each buffer_data chunk. */
  unsigned long size;

  /* For allocation. */
  struct buffer_data *unused_head;
  struct buffer_data *unused_tail;

  /* Current total length of this buffer. */
  unsigned long length;
};

/* Data container. */
struct buffer_data
{
  struct buffer_data *next;
  struct buffer_data *prev;

  /* Current pointer. */
  unsigned long cp;

  /* Start pointer. */
  unsigned long sp;

  /* Actual data stream (variable length). */
  unsigned char data[0];  /* real dimension is buffer->size */
};

/* Buffer prototypes. */
struct buffer *buffer_new (size_t);
int buffer_write (struct buffer *, const void *, size_t);
void buffer_free (struct buffer *);

/* Combine all accumulated (and unflushed) data inside the buffer into a
   single NUL-terminated string allocated using malloc (N.B. should be changed
   to use XMALLOC(MTYPE_TMP)).  Note that this function does not alter
   the state of the buffer, so the data is still inside waiting to be
   flushed. */
char *buffer_getstr (struct buffer *);

int buffer_putc (struct buffer *, u_char);
int buffer_putstr (struct buffer *, const char *);
void buffer_reset (struct buffer *);
int buffer_flush_all (struct buffer *, int);
int buffer_flush_vty_all (struct buffer *, int, int, int);
int buffer_flush_window (struct buffer *, int, int, int, int, int);
int buffer_empty (struct buffer *);

/* buffer_flush_available attempts to flush the queued data to the given
   file descriptor.  It returns 0 if the buffers are now empty (after
   flushing), or 1 if more data remains on the buffer queue (must be flushed
   later).  This function (unlike the other buffer_flush* functions) is
   designed to work with non-blocking file descriptors. */
int buffer_flush_available(struct buffer *, int fd);

#endif /* _ZEBRA_BUFFER_H */