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 "qemu/fifo8.h"
  17
  18void 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
  26void fifo8_destroy(Fifo8 *fifo)
  27{
  28    g_free(fifo->data);
  29}
  30
  31void 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
  40void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num)
  41{
  42    uint32_t start, avail;
  43
  44    if (fifo->num + num > fifo->capacity) {
  45        abort();
  46    }
  47
  48    start = (fifo->head + fifo->num) % fifo->capacity;
  49
  50    if (start + num <= fifo->capacity) {
  51        memcpy(&fifo->data[start], data, num);
  52    } else {
  53        avail = fifo->capacity - start;
  54        memcpy(&fifo->data[start], data, avail);
  55        memcpy(&fifo->data[0], &data[avail], num - avail);
  56    }
  57
  58    fifo->num += num;
  59}
  60
  61uint8_t fifo8_pop(Fifo8 *fifo)
  62{
  63    uint8_t ret;
  64
  65    if (fifo->num == 0) {
  66        abort();
  67    }
  68    ret = fifo->data[fifo->head++];
  69    fifo->head %= fifo->capacity;
  70    fifo->num--;
  71    return ret;
  72}
  73
  74const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num)
  75{
  76    uint8_t *ret;
  77
  78    if (max == 0 || max > fifo->num) {
  79        abort();
  80    }
  81    *num = MIN(fifo->capacity - fifo->head, max);
  82    ret = &fifo->data[fifo->head];
  83    fifo->head += *num;
  84    fifo->head %= fifo->capacity;
  85    fifo->num -= *num;
  86    return ret;
  87}
  88
  89void fifo8_reset(Fifo8 *fifo)
  90{
  91    fifo->num = 0;
  92    fifo->head = 0;
  93}
  94
  95bool fifo8_is_empty(Fifo8 *fifo)
  96{
  97    return (fifo->num == 0);
  98}
  99
 100bool fifo8_is_full(Fifo8 *fifo)
 101{
 102    return (fifo->num == fifo->capacity);
 103}
 104
 105uint32_t fifo8_num_free(Fifo8 *fifo)
 106{
 107    return fifo->capacity - fifo->num;
 108}
 109
 110uint32_t fifo8_num_used(Fifo8 *fifo)
 111{
 112    return fifo->num;
 113}
 114
 115const VMStateDescription vmstate_fifo8 = {
 116    .name = "Fifo8",
 117    .version_id = 1,
 118    .minimum_version_id = 1,
 119    .fields = (VMStateField[]) {
 120        VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, capacity),
 121        VMSTATE_UINT32(head, Fifo8),
 122        VMSTATE_UINT32(num, Fifo8),
 123        VMSTATE_END_OF_LIST()
 124    }
 125};
 126