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| | // SPDX-License-Identifier: GPL-2.0-or-later
/*
* iov.c - helpers for using (partial) iovecs.
*
* Copyrigh Red Hat
* Author: Laurent Vivier <lvivier@redhat.com>
*
* This file also contains code originally from QEMU include/qemu/iov.h:
*
* Author(s):
* Amit Shah <amit.shah@redhat.com>
* Michael Tokarev <mjt@tls.msk.ru>
*/
#ifndef IOVEC_H
#define IOVEC_H
#include <unistd.h>
#include <string.h>
#define IOV_OF_LVALUE(lval) \
(struct iovec){ .iov_base = &(lval), .iov_len = sizeof(lval) }
size_t iov_skip_bytes(const struct iovec *iov, size_t n,
size_t skip, size_t *offset);
size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
size_t offset, const void *buf, size_t bytes);
size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
size_t offset, void *buf, size_t bytes);
size_t iov_size(const struct iovec *iov, size_t iov_cnt);
/**
* struct iov_tail - Represents the fail portion of an IO vector
* @iov: IO vector
* @cnt: Number of entries in @iov
* @off: Current offset in @iov
*/
struct iov_tail {
const struct iovec *iov;
size_t cnt, off;
};
#define IOV_TAIL(iov_, cnt_, off_) \
(struct iov_tail){ .iov = (iov_), .cnt = (cnt_), .off = (off_) }
bool iov_tail_shorten(struct iov_tail *tail);
size_t iov_tail_size(struct iov_tail *tail);
void *iov_peek_header_(struct iov_tail *tail, size_t len, size_t align);
#define IOV_PEEK_HEADER(tail_, ty_) \
((ty_ *)(iov_peek_header_((tail_), sizeof(ty_), __alignof__(ty_))))
void *iov_pull_header_(struct iov_tail *tail, size_t len, size_t align);
#define IOV_PULL_HEADER(tail_, ty_) \
((ty_ *)(iov_pull_header_((tail_), sizeof(ty_), __alignof__(ty_))))
#endif /* IOVEC_H */
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