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/*
DeaDBeeF - ultimate music player for GNU/Linux systems with X11
Copyright (C) 2009-2012 Alexey Yakovenko <waker@users.sourceforge.net>
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; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <string.h>
#include "ringbuf.h"
void
ringbuf_init (ringbuf_t *p, char *buffer, size_t size) {
memset (p, 0, sizeof (ringbuf_t));
p->bytes = buffer;
p->cursor = 0;
p->size = size;
p->remaining = 0;
}
int
ringbuf_write (ringbuf_t *p, char *bytes, size_t size) {
if (p->size - p->remaining < size) {
return -1;
}
size_t cursor = p->cursor + p->remaining;
cursor %= p->size;
if (p->size - cursor >= size) { // split
memcpy (p->bytes + cursor, bytes, size);
p->remaining += size;
}
else {
size_t n = p->size - cursor;
if (n > 0) {
memcpy (p->bytes + cursor, bytes, n);
p->remaining += n;
size -= n;
bytes += n;
}
memcpy (p->bytes, bytes, size);
p->remaining += size;
}
return 0;
}
int
ringbuf_read (ringbuf_t *p, char *bytes, size_t size) {
if (p->remaining < size) {
size = p->remaining;
}
int rb = size;
if (p->size - p->cursor >= size) {
memcpy (bytes, p->bytes + p->cursor, size);
p->cursor += size;
p->remaining -= size;
}
else {
size_t n = p->size - p->cursor;
if (n > 0) {
memcpy (bytes, p->bytes + p->cursor, n);
p->cursor += n;
p->remaining -= n;
bytes += n;
size -= n;
}
memcpy (bytes, p->bytes, size);
p->cursor = size;
p->remaining -= size;
}
return rb;
}
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