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102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
/*
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* Copyright (C) 2018 Kaspar Schleiser <kaspar@schleiser.de>
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* 2018 Inria
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* 2018 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @defgroup sys_iolist iolist scatter / gather IO
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* @ingroup sys
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* @brief Provides linked-list scatter / gather IO
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*
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* @{
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*
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* @file
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* @brief iolist scatter / gather IO
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*
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* @author Kaspar Schleiser <kaspar@schleiser.de>
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*/
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#ifndef IOLIST_H
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#define IOLIST_H
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#include <unistd.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** @brief iolist forward declaration */
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typedef struct iolist iolist_t;
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/**
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* @brief iolist structure definition
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*/
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struct iolist {
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iolist_t *iol_next; /**< ptr to next list entry */
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void *iol_base; /**< ptr to this list entries data */
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size_t iol_len; /**< size of data pointet to by ptr */
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};
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/**
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* @brief Count number of entries in an iolist_t
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*
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* @param[in] iolist iolist to count
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*
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* @returns number of entries (zero for NULL parameter)
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*/
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unsigned iolist_count(const iolist_t *iolist);
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/**
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* @brief Sum up number of bytes in iolist
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*
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* This function returns the summed ip length values of all entries in @p
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* iolist.
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*
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* @param[in] iolist iolist to sum up
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*
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* @returns summed up number of bytes or zero if @p iolist == NULL
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*/
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size_t iolist_size(const iolist_t *iolist);
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/** @brief struct iovec anonymous declaration */
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struct iovec;
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/**
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* @brief Create struct iovec from iolist
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*
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* This function fills an array of struct iovecs with the contents of @p
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* iolist. It will write the number of used array entries into @p count.
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*
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* The caller *must* ensure that @p iov p points to an array of size >= count!
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*
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* @param[in] iolist iolist to read from
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* @param[out] iov ptr to array of struct iovec that will be filled
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* @param[out] count number of elements in @p iolist
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*
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* @returns iolist_size(iolist)
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*/
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size_t iolist_to_iovec(const iolist_t *iolist, struct iovec *iov, unsigned *count);
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/**
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* @brief Copies the bytes of the iolist to a buffer
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*
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* @param[in] iolist iolist to read from
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* @param[out] dst Destination buffer
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* @param[in] len Size of the destination buffer
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*
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* @returns iolist_size(iolist) on success
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* -ENOBUFS if the buffer is too small
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*/
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ssize_t iolist_to_buffer(const iolist_t *iolist, void *dst, size_t len);
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#ifdef __cplusplus
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}
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#endif
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#endif /* IOLIST_H */
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/** @} */
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