qemu-e2k/util/fifo8.c

126 lines
2.7 KiB
C

/*
* 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-common.h"
#include "qemu/fifo8.h"
void fifo8_create(Fifo8 *fifo, uint32_t capacity)
{
fifo->data = g_new(uint8_t, capacity);
fifo->capacity = capacity;
fifo->head = 0;
fifo->num = 0;
}
void fifo8_destroy(Fifo8 *fifo)
{
g_free(fifo->data);
}
void fifo8_push(Fifo8 *fifo, uint8_t data)
{
if (fifo->num == fifo->capacity) {
abort();
}
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;
if (fifo->num + num > fifo->capacity) {
abort();
}
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;
if (fifo->num == 0) {
abort();
}
ret = fifo->data[fifo->head++];
fifo->head %= fifo->capacity;
fifo->num--;
return ret;
}
const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num)
{
uint8_t *ret;
if (max == 0 || max > fifo->num) {
abort();
}
*num = MIN(fifo->capacity - fifo->head, max);
ret = &fifo->data[fifo->head];
fifo->head += *num;
fifo->head %= fifo->capacity;
fifo->num -= *num;
return ret;
}
void fifo8_reset(Fifo8 *fifo)
{
fifo->num = 0;
fifo->head = 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 = (VMStateField[]) {
VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, 0, capacity),
VMSTATE_UINT32(head, Fifo8),
VMSTATE_UINT32(num, Fifo8),
VMSTATE_END_OF_LIST()
}
};