/*
 * $Id: ggep.h,v 1.5 2005/05/03 21:01:07 cbiere Exp $
 *
 * Copyright (c) 2002-2003, Raphael Manfredi
 *
 * Gnutella Generic Extension Protocol (GGEP).
 *
 *----------------------------------------------------------------------
 * This file is part of gtk-gnutella.
 *
 *  gtk-gnutella 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 of the License, or
 *  (at your option) any later version.
 *
 *  gtk-gnutella 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 gtk-gnutella; if not, write to the Free Software
 *  Foundation, Inc.:
 *      59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *----------------------------------------------------------------------
 */

#ifndef _core_ggep_h_
#define _core_ggep_h_

#include "extensions.h"
#include "lib/cobs.h"
#include "lib/zlib_util.h"

#include <glib.h>

#define GGEP_MAGIC		'\xc3'		/* GGEP extension prefix */

/*
 * GGEP Extension Header Flags.
 */

#define GGEP_F_LAST		0x80U		/* Last extension in GGEP block */
#define GGEP_F_COBS		0x40U		/* Whether COBS was used on payload */
#define GGEP_F_DEFLATE	0x20U		/* Whether payload was deflated */
#define GGEP_F_MBZ		0x10U		/* Bits that Must Be Zero */
#define GGEP_F_IDLEN	0x0fU		/* Where ID length is stored */

/*
 * GGEP Length Encoding.
 */

#define GGEP_L_CONT		'\x80'		/* Continuation present */
#define GGEP_L_LAST		'\x40'		/* Last byte */
#define GGEP_L_VALUE	'\x3f'		/* Value */
#define GGEP_L_VSHIFT	6

#define GGEP_L_XFLAGS	(GGEP_L_CONT | GGEP_L_LAST)

/*
 * The "H" extension
 */

#define GGEP_H_SHA1		0x01		/* Binary SHA1 */
#define GGEP_H_BITPRINT	0x02		/* Bitprint (SHA1 + Tiger tree root) */
#define GGEP_H_MD5		0x03		/* Binary MD5 */
#define GGEP_H_UUID		0x04		/* Binary UUID (GUID-like) */
#define GGEP_H_MD4		0x05		/* Binary MD4 */

/*
 * Flags for ggep_ext_write() and friends.
 */

#define GGEP_W_LAST		0x00000001	/* This is the last extension */
#define GGEP_W_COBS		0x00000002	/* Attempt COBS encoding, if needed */
#define GGEP_W_DEFLATE	0x00000004	/* Attempt payload compression */
#define GGEP_W_FIRST	0x00000008	/* First extension, write GGEP_MAGIC */

/*
 * Structure keeping track of incremental GGEP writes.
 */
typedef struct ggep_stream {
	gchar *outbuf;				/* Base address of output buffer */
	gchar *end;					/* First address beyond output buffer */
	gchar *o;					/* Where next output should go */
	gchar *fp;					/* Where flags for current extension are */
	gchar *lp;					/* Where length should be written when known */
	gchar *last_fp;				/* Flags of last successfully written ext. */
	size_t size;				/* Size of the outbuf buffer */
	guint8 flags;				/* Extension flags (COBS / DEFLATE) */
	gboolean magic_emitted;		/* Whether leading magic was emitted */
	gboolean begun;				/* Whether extension was correctly begun */
	cobs_stream_t cs;			/* Used if COBS needed */
	zlib_deflater_t *zd;		/* Allocated and used if deflation needed */
} ggep_stream_t;

/*
 * Public interface.
 */

struct iovec;

gint ggep_decode_into(extvec_t *exv, gchar *buf, size_t len);

void ggep_stream_init(ggep_stream_t *gs, gpointer data, size_t len);
gboolean ggep_stream_begin(ggep_stream_t *gs, gchar *id, guint32 wflags);
gboolean ggep_stream_writev(ggep_stream_t *gs, struct iovec *iov, gint iovcnt);
gboolean ggep_stream_write(ggep_stream_t *gs, gpointer data, size_t len);
gboolean ggep_stream_end(ggep_stream_t *gs);
size_t ggep_stream_close(ggep_stream_t *gs);
gboolean ggep_stream_packv(ggep_stream_t *gs,
	gchar *id, struct iovec *iov, gint iovcnt, guint32 wflags);
gboolean ggep_stream_pack(ggep_stream_t *gs,
	gchar *id, gchar *payload, size_t plen, guint32 wflags);

#endif	/* _core_ggep_h_ */

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