LXR qemu/util/fifo8.c

   1/*
   2 * Generic FIFO component, implemented as a circular buffer.
   3 *
   4 * Copyright (c) 2012 Peter A. G. Crosthwaite
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 *
  11 * You should have received a copy of the GNU General Public License along
  12 * with this program; if not, see <http://www.gnu.org/licenses/>.
  13 */
  14
  15#include "qemu/osdep.h"
  16#include "migration/vmstate.h"
  17#include "qemu/fifo8.h"
  18
  19void fifo8_create(Fifo8 *fifo, uint32_t capacity)
  20{
  21    fifo->data = g_new(uint8_t, capacity);
  22    fifo->capacity = capacity;
  23    fifo->head = 0;
  24    fifo->num = 0;
  25}
  26
  27void fifo8_destroy(Fifo8 *fifo)
  28{
  29    g_free(fifo->data);
  30}
  31
  32void fifo8_push(Fifo8 *fifo, uint8_t data)
  33{
  34    assert(fifo->num < fifo->capacity);
  35    fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data;
  36    fifo->num++;
  37}
  38
  39void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num)
  40{
  41    uint32_t start, avail;
  42
  43    assert(fifo->num + num <= fifo->capacity);
  44
  45    start = (fifo->head + fifo->num) % fifo->capacity;
  46
  47    if (start + num <= fifo->capacity) {
  48        memcpy(&fifo->data[start], data, num);
  49    } else {
  50        avail = fifo->capacity - start;
  51        memcpy(&fifo->data[start], data, avail);
  52        memcpy(&fifo->data[0], &data[avail], num - avail);
  53    }
  54
  55    fifo->num += num;
  56}
  57
  58uint8_t fifo8_pop(Fifo8 *fifo)
  59{
  60    uint8_t ret;
  61
  62    assert(fifo->num > 0);
  63    ret = fifo->data[fifo->head++];
  64    fifo->head %= fifo->capacity;
  65    fifo->num--;
  66    return ret;
  67}
  68
  69const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num)
  70{
  71    uint8_t *ret;
  72
  73    assert(max > 0 && max <= fifo->num);
  74    *num = MIN(fifo->capacity - fifo->head, max);
  75    ret = &fifo->data[fifo->head];
  76    fifo->head += *num;
  77    fifo->head %= fifo->capacity;
  78    fifo->num -= *num;
  79    return ret;
  80}
  81
  82void fifo8_reset(Fifo8 *fifo)
  83{
  84    fifo->num = 0;
  85    fifo->head = 0;
  86}
  87
  88bool fifo8_is_empty(Fifo8 *fifo)
  89{
  90    return (fifo->num == 0);
  91}
  92
  93bool fifo8_is_full(Fifo8 *fifo)
  94{
  95    return (fifo->num == fifo->capacity);
  96}
  97
  98uint32_t fifo8_num_free(Fifo8 *fifo)
  99{
 100    return fifo->capacity - fifo->num;
 101}
 102
 103uint32_t fifo8_num_used(Fifo8 *fifo)
 104{
 105    return fifo->num;
 106}
 107
 108const VMStateDescription vmstate_fifo8 = {
 109    .name = "Fifo8",
 110    .version_id = 1,
 111    .minimum_version_id = 1,
 112    .fields = (VMStateField[]) {
 113        VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, capacity),
 114        VMSTATE_UINT32(head, Fifo8),
 115        VMSTATE_UINT32(num, Fifo8),
 116        VMSTATE_END_OF_LIST()
 117    }
 118};
 119