e0dd92729e
New "struct ring" object that implements a basic ring buffer for arbitrary byte-streams. A new basic runtime test is also added. This will be needed for our pty helpers for systemd-console and friends.
60 lines
1.8 KiB
C
60 lines
1.8 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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#pragma once
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/***
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This file is part of systemd.
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Copyright 2014 David Herrmann <dh.herrmann@gmail.com>
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <inttypes.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/uio.h>
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struct ring {
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uint8_t *buf; /* buffer or NULL */
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size_t size; /* actual size of @buf */
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size_t start; /* start position of ring */
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size_t used; /* number of actually used bytes */
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};
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/* flush buffer so it is empty again */
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void ring_flush(struct ring *r);
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/* flush buffer, free allocated data and reset to initial state */
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void ring_clear(struct ring *r);
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/* get pointers to buffer data and their length */
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size_t ring_peek(struct ring *r, struct iovec *vec);
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/* copy data into external linear buffer */
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size_t ring_copy(struct ring *r, void *buf, size_t size);
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/* push data to the end of the buffer */
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int ring_push(struct ring *r, const void *u8, size_t size);
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/* pull data from the front of the buffer */
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void ring_pull(struct ring *r, size_t size);
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/* return size of occupied buffer in bytes */
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static inline size_t ring_get_size(struct ring *r)
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{
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return r->used;
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}
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