+++ /dev/null
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
- This file is part of systemd.
-
- Copyright 2014 David Herrmann <dh.herrmann@gmail.com>
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd 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
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
-
-#include <errno.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/uio.h>
-#include "macro.h"
-#include "ring.h"
-
-#define RING_MASK(_r, _v) ((_v) & ((_r)->size - 1))
-
-void ring_flush(Ring *r) {
- assert(r);
-
- r->start = 0;
- r->used = 0;
-}
-
-void ring_clear(Ring *r) {
- assert(r);
-
- free(r->buf);
- zero(*r);
-}
-
-/*
- * Get data pointers for current ring-buffer data. @vec must be an array of 2
- * iovec objects. They are filled according to the data available in the
- * ring-buffer. 0, 1 or 2 is returned according to the number of iovec objects
- * that were filled (0 meaning buffer is empty).
- *
- * Hint: "struct iovec" is defined in <sys/uio.h> and looks like this:
- * struct iovec {
- * void *iov_base;
- * size_t iov_len;
- * };
- */
-size_t ring_peek(Ring *r, struct iovec *vec) {
- assert(r);
-
- if (r->used == 0) {
- return 0;
- } else if (r->start + r->used <= r->size) {
- if (vec) {
- vec[0].iov_base = &r->buf[r->start];
- vec[0].iov_len = r->used;
- }
- return 1;
- } else {
- if (vec) {
- vec[0].iov_base = &r->buf[r->start];
- vec[0].iov_len = r->size - r->start;
- vec[1].iov_base = r->buf;
- vec[1].iov_len = r->used - (r->size - r->start);
- }
- return 2;
- }
-}
-
-/*
- * Copy data from the ring buffer into the linear external buffer @buf. Copy
- * at most @size bytes. If the ring buffer size is smaller, copy less bytes and
- * return the number of bytes copied.
- */
-size_t ring_copy(Ring *r, void *buf, size_t size) {
- size_t l;
-
- assert(r);
- assert(buf);
-
- if (size > r->used)
- size = r->used;
-
- if (size > 0) {
- l = r->size - r->start;
- if (size <= l) {
- memcpy(buf, &r->buf[r->start], size);
- } else {
- memcpy(buf, &r->buf[r->start], l);
- memcpy((uint8_t*)buf + l, r->buf, size - l);
- }
- }
-
- return size;
-}
-
-/*
- * Resize ring-buffer to size @nsize. @nsize must be a power-of-2, otherwise
- * ring operations will behave incorrectly.
- */
-static int ring_resize(Ring *r, size_t nsize) {
- uint8_t *buf;
- size_t l;
-
- assert(r);
- assert(nsize > 0);
-
- buf = malloc(nsize);
- if (!buf)
- return -ENOMEM;
-
- if (r->used > 0) {
- l = r->size - r->start;
- if (r->used <= l) {
- memcpy(buf, &r->buf[r->start], r->used);
- } else {
- memcpy(buf, &r->buf[r->start], l);
- memcpy(&buf[l], r->buf, r->used - l);
- }
- }
-
- free(r->buf);
- r->buf = buf;
- r->size = nsize;
- r->start = 0;
-
- return 0;
-}
-
-/*
- * Resize ring-buffer to provide enough room for @add bytes of new data. This
- * resizes the buffer if it is too small. It returns -ENOMEM on OOM and 0 on
- * success.
- */
-static int ring_grow(Ring *r, size_t add) {
- size_t need;
-
- assert(r);
-
- if (r->size - r->used >= add)
- return 0;
-
- need = r->used + add;
- if (need <= r->used)
- return -ENOMEM;
- else if (need < 4096)
- need = 4096;
-
- need = ALIGN_POWER2(need);
- if (need == 0)
- return -ENOMEM;
-
- return ring_resize(r, need);
-}
-
-/*
- * Push @len bytes from @u8 into the ring buffer. The buffer is resized if it
- * is too small. -ENOMEM is returned on OOM, 0 on success.
- */
-int ring_push(Ring *r, const void *u8, size_t size) {
- int err;
- size_t pos, l;
-
- assert(r);
- assert(u8);
-
- if (size == 0)
- return 0;
-
- err = ring_grow(r, size);
- if (err < 0)
- return err;
-
- pos = RING_MASK(r, r->start + r->used);
- l = r->size - pos;
- if (l >= size) {
- memcpy(&r->buf[pos], u8, size);
- } else {
- memcpy(&r->buf[pos], u8, l);
- memcpy(r->buf, (const uint8_t*)u8 + l, size - l);
- }
-
- r->used += size;
-
- return 0;
-}
-
-/*
- * Remove @len bytes from the start of the ring-buffer. Note that we protect
- * against overflows so removing more bytes than available is safe.
- */
-void ring_pull(Ring *r, size_t size) {
- assert(r);
-
- if (size > r->used)
- size = r->used;
-
- r->start = RING_MASK(r, r->start + size);
- r->used -= size;
-}
~ianmdlvl / elogind.git / blobdiff