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    if (fifo->num == fifo->capacity) {
  35        abort();
  36    }
  37    fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data;
  38    fifo->num++;
  39}
  40
  41void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num)
  42{
  43    uint32_t start, avail;
  44
  45    if (fifo->num + num > fifo->capacity) {
  46        abort();
  47    }
  48
  49    start = (fifo->head + fifo->num) % fifo->capacity;
  50
  51    if (start + num <= fifo->capacity) {
  52        memcpy(&fifo->data[start], data, num);
  53    } else {
  54        avail = fifo->capacity - start;
  55        memcpy(&fifo->data[start], data, avail);
  56        memcpy(&fifo->data[0], &data[avail], num - avail);
  57    }
  58
  59    fifo->num += num;
  60}
  61
  62uint8_t fifo8_pop(Fifo8 *fifo)
  63{
  64    uint8_t ret;
  65
  66    if (fifo->num == 0) {
  67        abort();
  68    }
  69    ret = fifo->data[fifo->head++];
  70    fifo->head %= fifo->capacity;
  71    fifo->num--;
  72    return ret;
  73}
  74
  75const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num)
  76{
  77    uint8_t *ret;
  78
  79    if (max == 0 || max > fifo->num) {
  80        abort();
  81    }
  82    *num = MIN(fifo->capacity - fifo->head, max);
  83    ret = &fifo->data[fifo->head];
  84    fifo->head += *num;
  85    fifo->head %= fifo->capacity;
  86    fifo->num -= *num;
  87    return ret;
  88}
  89
  90void fifo8_reset(Fifo8 *fifo)
  91{
  92    fifo->num = 0;
  93    fifo->head = 0;
  94}
  95
  96bool fifo8_is_empty(Fifo8 *fifo)
  97{
  98    return (fifo->num == 0);
  99}
 100
 101bool fifo8_is_full(Fifo8 *fifo)
 102{
 103    return (fifo->num == fifo->capacity);
 104}
 105
 106uint32_t fifo8_num_free(Fifo8 *fifo)
 107{
 108    return fifo->capacity - fifo->num;
 109}
 110
 111uint32_t fifo8_num_used(Fifo8 *fifo)
 112{
 113    return fifo->num;
 114}
 115
 116const VMStateDescription vmstate_fifo8 = {
 117    .name = "Fifo8",
 118    .version_id = 1,
 119    .minimum_version_id = 1,
 120    .fields = (VMStateField[]) {
 121        VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, capacity),
 122        VMSTATE_UINT32(head, Fifo8),
 123        VMSTATE_UINT32(num, Fifo8),
 124        VMSTATE_END_OF_LIST()
 125    }
 126};
 127