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/*
* Generic FIFO component, implemented as a circular buffer.
*
* Copyright (c) 2012 Peter A. G. Crosthwaite
*
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "migration/vmstate.h"
#include "qemu/fifo8.h"
void fifo8_reset(Fifo8 *fifo)
{
fifo->num = 0;
fifo->head = 0;
}
void fifo8_create(Fifo8 *fifo, uint32_t capacity)
{
fifo->data = g_new(uint8_t, capacity);
fifo->capacity = capacity;
fifo8_reset(fifo);
}
void fifo8_destroy(Fifo8 *fifo)
{
g_free(fifo->data);
}
void fifo8_push(Fifo8 *fifo, uint8_t data)
{
assert(fifo->num < fifo->capacity);
fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data;
fifo->num++;
}
void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num)
{
uint32_t start, avail;
assert(fifo->num + num <= fifo->capacity);
start = (fifo->head + fifo->num) % fifo->capacity;
if (start + num <= fifo->capacity) {
memcpy(&fifo->data[start], data, num);
} else {
avail = fifo->capacity - start;
memcpy(&fifo->data[start], data, avail);
memcpy(&fifo->data[0], &data[avail], num - avail);
}
fifo->num += num;
}
uint8_t fifo8_pop(Fifo8 *fifo)
{
uint8_t ret;
assert(fifo->num > 0);
ret = fifo->data[fifo->head++];
fifo->head %= fifo->capacity;
fifo->num--;
return ret;
}
static const uint8_t *fifo8_peekpop_buf(Fifo8 *fifo, uint32_t max,
uint32_t *numptr, bool do_pop)
{
uint8_t *ret;
uint32_t num;
assert(max > 0 && max <= fifo->num);
num = MIN(fifo->capacity - fifo->head, max);
ret = &fifo->data[fifo->head];
if (do_pop) {
fifo->head += num;
fifo->head %= fifo->capacity;
fifo->num -= num;
}
if (numptr) {
*numptr = num;
}
return ret;
}
const uint8_t *fifo8_peek_bufptr(Fifo8 *fifo, uint32_t max, uint32_t *numptr)
{
return fifo8_peekpop_buf(fifo, max, numptr, false);
}
const uint8_t *fifo8_pop_bufptr(Fifo8 *fifo, uint32_t max, uint32_t *numptr)
{
return fifo8_peekpop_buf(fifo, max, numptr, true);
}
uint32_t fifo8_pop_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen)
{
const uint8_t *buf;
uint32_t n1, n2 = 0;
uint32_t len;
if (destlen == 0) {
return 0;
}
len = destlen;
buf = fifo8_pop_bufptr(fifo, len, &n1);
if (dest) {
memcpy(dest, buf, n1);
}
/* Add FIFO wraparound if needed */
len -= n1;
len = MIN(len, fifo8_num_used(fifo));
if (len) {
buf = fifo8_pop_bufptr(fifo, len, &n2);
if (dest) {
memcpy(&dest[n1], buf, n2);
}
}
return n1 + n2;
}
void fifo8_drop(Fifo8 *fifo, uint32_t len)
{
len -= fifo8_pop_buf(fifo, NULL, len);
assert(len == 0);
}
bool fifo8_is_empty(Fifo8 *fifo)
{
return (fifo->num == 0);
}
bool fifo8_is_full(Fifo8 *fifo)
{
return (fifo->num == fifo->capacity);
}
uint32_t fifo8_num_free(Fifo8 *fifo)
{
return fifo->capacity - fifo->num;
}
uint32_t fifo8_num_used(Fifo8 *fifo)
{
return fifo->num;
}
const VMStateDescription vmstate_fifo8 = {
.name = "Fifo8",
.version_id = 1,
.minimum_version_id = 1,
.fields = (const VMStateField[]) {
VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, capacity),
VMSTATE_UINT32(head, Fifo8),
VMSTATE_UINT32(num, Fifo8),
VMSTATE_END_OF_LIST()
}
};
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