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-common.h"
  16 #include "qemu/fifo8.h"
  17
  18 void fifo8_create(Fifo8 *fifo, uint32_t capacity)
  19 {
  20     fifo->data = g_new(uint8_t, capacity);
  21     fifo->capacity = capacity;
  22     fifo->head = 0;
  23     fifo->num = 0;
  24 }
  25
  26 void fifo8_destroy(Fifo8 *fifo)
  27 {
  28     g_free(fifo->data);
  29 }
  30
  31 void fifo8_push(Fifo8 *fifo, uint8_t data)
  32 {
  33     if (fifo->num == fifo->capacity) {
  34         abort();
  35     }
  36     fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data;
  37     fifo->num++;
  38 }
  39
  40 uint8_t fifo8_pop(Fifo8 *fifo)
  41 {
  42     uint8_t ret;
  43
  44     if (fifo->num == 0) {
  45         abort();
  46     }
  47     ret = fifo->data[fifo->head++];
  48     fifo->head %= fifo->capacity;
  49     fifo->num--;
  50     return ret;
  51 }
  52
  53 void fifo8_reset(Fifo8 *fifo)
  54 {
  55     fifo->num = 0;
  56 }
  57
  58 bool fifo8_is_empty(Fifo8 *fifo)
  59 {
  60     return (fifo->num == 0);
  61 }
  62
  63 bool fifo8_is_full(Fifo8 *fifo)
  64 {
  65     return (fifo->num == fifo->capacity);
  66 }
  67
  68 const VMStateDescription vmstate_fifo8 = {
  69     .name = "Fifo8",
  70     .version_id = 1,
  71     .minimum_version_id = 1,
  72     .minimum_version_id_old = 1,
  73     .fields      = (VMStateField[]) {
  74         VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, 0, capacity),
  75         VMSTATE_UINT32(head, Fifo8),
  76         VMSTATE_UINT32(num, Fifo8),
  77         VMSTATE_END_OF_LIST()
  78     }
  79 };