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/************************************************************************
* IRC - Internet Relay Chat, common/dbuf_def.h
* Copyright (C) 1990 Markku Savela
*
* 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 1, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#define DBUF_TAIL
/*
** dbuf is a collection of functions which can be used to
** maintain a dynamic buffering of a byte stream.
** Functions allocate and release memory dynamically as
** required [Actually, there is nothing that prevents
** this package maintaining the buffer on disk, either]
*/
/*
** These structure definitions are only here to be used
** as a whole, *DO NOT EVER REFER TO THESE FIELDS INSIDE
** THE STRUCTURES*! It must be possible to change the internal
** implementation of this package without changing the
** interface.
*/
#if !defined(_SEQUENT_)
typedef struct dbuf
{
u_int length; /* Current number of bytes stored */
u_int offset; /* Offset to the first byte */
struct dbufbuf *head; /* First data buffer, if length > 0 */
#ifdef DBUF_TAIL
/* added by mnystrom@mit.edu: */
struct dbufbuf *tail; /* last data buffer, if length > 0 */
#endif
} dbuf;
#else
typedef struct dbuf
{
uint length; /* Current number of bytes stored */
uint offset; /* Offset to the first byte */
struct dbufbuf *head; /* First data buffer, if length > 0 */
#ifdef DBUF_TAIL
/* added by mnystrom@mit.edu: */
struct dbufbuf *tail; /* last data buffer, if length > 0 */
#endif
} dbuf;
#endif
/*
** And this 'dbufbuf' should never be referenced outside the
** implementation of 'dbuf'--would be "hidden" if C had such
** keyword...
** If it was possible, this would compile to be exactly 1 memory
** page in size. 2048 bytes seems to be the most common size, so
** as long as a pointer is 4 bytes, we get 2032 bytes for buffer
** data after we take away a bit for malloc to play with. -avalon
*/
typedef struct dbufbuf
{
struct dbufbuf *next; /* Next data buffer, NULL if this is last */
char data[2032]; /* Actual data stored here */
} dbufbuf;
/*
** DBufLength
** Return the current number of bytes stored into the buffer.
** (One should use this instead of referencing the internal
** length field explicitly...)
*/
#define DBufLength(dyn) ((dyn)->length)
/*
** DBufClear
** Scratch the current content of the buffer. Release all
** allocated buffers and make it empty.
*/
#define DBufClear(dyn) dbuf_delete((dyn),DBufLength(dyn))
/* This is a dangerous define because a broken compiler will set DBUFSIZ
** to 4, which will work but will be very inefficient. However, there
** are other places where the code breaks badly if this is screwed
** up, so... -- Wumpus
*/
#define DBUFSIZ sizeof(((dbufbuf *)0)->data)
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