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/*
* Circular buffer implementation.
* Copyright (C) 2017 Cumulus Networks
* Quentin Young
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program 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 General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <zebra.h>
#include "ringbuf.h"
#include "memory.h"
DEFINE_MTYPE_STATIC(LIB, RINGBUFFER, "Ring buffer")
struct ringbuf *ringbuf_new(size_t size)
{
struct ringbuf *buf = XCALLOC(MTYPE_RINGBUFFER, sizeof(struct ringbuf));
buf->data = XCALLOC(MTYPE_RINGBUFFER, size);
buf->size = size;
buf->empty = true;
return buf;
}
void ringbuf_del(struct ringbuf *buf)
{
XFREE(MTYPE_RINGBUFFER, buf->data);
XFREE(MTYPE_RINGBUFFER, buf);
}
size_t ringbuf_remain(struct ringbuf *buf)
{
ssize_t diff = buf->end - buf->start;
diff += ((diff == 0) && !buf->empty) ? buf->size : 0;
diff += (diff < 0) ? buf->size : 0;
return (size_t)diff;
}
size_t ringbuf_space(struct ringbuf *buf)
{
return buf->size - ringbuf_remain(buf);
}
size_t ringbuf_put(struct ringbuf *buf, const void *data, size_t size)
{
const uint8_t *dp = data;
size_t space = ringbuf_space(buf);
size_t copysize = MIN(size, space);
size_t tocopy = copysize;
if (tocopy >= buf->size - buf->end) {
size_t ts = buf->size - buf->end;
memcpy(buf->data + buf->end, dp, ts);
buf->end = 0;
tocopy -= ts;
dp += ts;
}
memcpy(buf->data + buf->end, dp, tocopy);
buf->end += tocopy;
buf->empty = (buf->start == buf->end) && (buf->empty && !copysize);
return copysize;
}
size_t ringbuf_get(struct ringbuf *buf, void *data, size_t size)
{
uint8_t *dp = data;
size_t remain = ringbuf_remain(buf);
size_t copysize = MIN(remain, size);
size_t tocopy = copysize;
if (tocopy >= buf->size - buf->start) {
size_t ts = buf->size - buf->start;
memcpy(dp, buf->data + buf->start, ts);
buf->start = 0;
tocopy -= ts;
dp += ts;
}
memcpy(dp, buf->data + buf->start, tocopy);
buf->start = buf->start + tocopy;
buf->empty = (buf->start == buf->end) && (buf->empty || copysize);
return copysize;
}
size_t ringbuf_peek(struct ringbuf *buf, size_t offset, void *data, size_t size)
{
uint8_t *dp = data;
size_t remain = ringbuf_remain(buf);
if (offset >= remain)
return 0;
size_t copysize = MAX(MIN(remain - offset, size), (size_t)0);
size_t tocopy = copysize;
size_t cstart = (buf->start + offset) % buf->size;
if (tocopy >= buf->size - cstart) {
size_t ts = buf->size - cstart;
memcpy(dp, buf->data + cstart, ts);
cstart = 0;
tocopy -= ts;
dp += ts;
}
memcpy(dp, buf->data + cstart, tocopy);
return copysize;
}
size_t ringbuf_copy(struct ringbuf *to, struct ringbuf *from, size_t size)
{
size_t tocopy = MIN(ringbuf_space(to), size);
uint8_t *cbuf = XCALLOC(MTYPE_TMP, tocopy);
tocopy = ringbuf_peek(from, 0, cbuf, tocopy);
size_t put = ringbuf_put(to, cbuf, tocopy);
XFREE(MTYPE_TMP, cbuf);
return put;
}
void ringbuf_reset(struct ringbuf *buf)
{
buf->start = buf->end = 0;
buf->empty = true;
}
void ringbuf_wipe(struct ringbuf *buf)
{
memset(buf->data, 0x00, buf->size);
ringbuf_reset(buf);
}
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