/*	$NetBSD: uio.h,v 1.12 2018/11/30 09:53:40 hannken Exp $	*/

/*-
 * Copyright (c) 2009 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Andrew Doran.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*-
 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: head/sys/cddl/compat/opensolaris/sys/uio.h 219089 2011-02-27 19:41:40Z pjd $
 */

#ifndef _OPENSOLARIS_SYS_UIO_H_
#define	_OPENSOLARIS_SYS_UIO_H_

#include_next <sys/uio.h>
#include <sys/debug.h>

#ifndef _KERNEL
#include <assert.h>
#include <string.h>

#define	FOF_OFFSET	1	/* Use the offset in uio argument */

struct uio {
	struct	iovec *uio_iov;
	int	uio_iovcnt;
	off_t	uio_offset;
	int	uio_resid;
	enum	uio_seg uio_segflg;
	enum	uio_rw uio_rw;
	void	*uio_td;
};
#endif

struct xuio {
	struct uio xu_uio;
	int	xuio_rw;
	void *xuio_priv;
};

#define XUIO_XUZC_PRIV(xuio)	((xuio)->xuio_priv)
#define XUIO_XUZC_RW(xuio)	((xuio)->xuio_rw)

typedef	struct uio	uio_t;
typedef struct xuio	xuio_t;
typedef	struct iovec	iovec_t;

typedef enum uio_seg    uio_seg_t;

#define	uio_loffset	uio_offset

int	uiomove(void *, size_t, struct uio *);

static __inline int
zfs_uiomove(void *cp, size_t n, enum uio_rw dir, uio_t *uio)
{

	assert(uio->uio_rw == dir);
	return (uiomove(cp, n, uio));
}

#define	ZFS_MIN(a,b)	((/*CONSTCOND*/(a)<(b))?(a):(b))

static __inline int
zfs_uiocopy(void *cp, size_t n, enum uio_rw dir, uio_t *uio, size_t *cbytes)
{
	uio_t auio;
	struct iovec aiov;
	size_t cnt;
	int i, error;

	*cbytes = 0;
	memcpy(&auio, uio, sizeof(*uio));
	for (i = 0; i < uio->uio_iovcnt && n > 0; i++) {
		auio.uio_iov = &aiov;
		auio.uio_iovcnt = 1;
		aiov = uio->uio_iov[i];
		cnt = ZFS_MIN(aiov.iov_len, n);
		if (cnt == 0)
			continue;
		error = uiomove(cp, cnt, &auio);
		if (error)
			return error;
		cp = (char *)cp + cnt;
		n -= cnt;
		*cbytes += cnt;
	}

	return 0;
}

static __inline void
zfs_uioskip(uio_t *uiop, size_t n)
{
	if (n > (size_t)uiop->uio_resid)
		return;
	while (n != 0) {
		iovec_t        *iovp = uiop->uio_iov;
		size_t         niovb = ZFS_MIN(iovp->iov_len, n);

		if (niovb == 0) {
			uiop->uio_iov++;
			uiop->uio_iovcnt--;
			continue;
		}
		iovp->iov_base = (char *)iovp->iov_base + niovb;
		uiop->uio_offset += (off_t)niovb;
		iovp->iov_len -= niovb;
		uiop->uio_resid -= (int)niovb;
		n -= niovb;
	}
	
}

#define	uiomove(cp, n, dir, uio)	zfs_uiomove((cp), (n), (dir), (uio))
#define uiocopy(cp, n, dir, uio, cbytes) 	zfs_uiocopy((cp), (n), (dir), (uio), (cbytes))
#define uioskip(uio, size) 		zfs_uioskip((uio), (size))

#endif	/* !_OPENSOLARIS_SYS_UIO_H_ */