| 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 | |
| 19 | void fifo8_reset(Fifo8 *fifo) |
| 20 | { |
| 21 | fifo->num = 0; |
| 22 | fifo->head = 0; |
| 23 | } |
| 24 | |
| 25 | void fifo8_create(Fifo8 *fifo, uint32_t capacity) |
| 26 | { |
| 27 | fifo->data = g_new(uint8_t, capacity); |
| 28 | fifo->capacity = capacity; |
| 29 | fifo8_reset(fifo); |
| 30 | } |
| 31 | |
| 32 | void fifo8_destroy(Fifo8 *fifo) |
| 33 | { |
| 34 | g_free(fifo->data); |
| 35 | } |
| 36 | |
| 37 | void fifo8_push(Fifo8 *fifo, uint8_t data) |
| 38 | { |
| 39 | assert(fifo->num < fifo->capacity); |
| 40 | fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data; |
| 41 | fifo->num++; |
| 42 | } |
| 43 | |
| 44 | void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num) |
| 45 | { |
| 46 | uint32_t start, avail; |
| 47 | |
| 48 | assert(fifo->num + num <= fifo->capacity); |
| 49 | |
| 50 | start = (fifo->head + fifo->num) % fifo->capacity; |
| 51 | |
| 52 | if (start + num <= fifo->capacity) { |
| 53 | memcpy(&fifo->data[start], data, num); |
| 54 | } else { |
| 55 | avail = fifo->capacity - start; |
| 56 | memcpy(&fifo->data[start], data, avail); |
| 57 | memcpy(&fifo->data[0], &data[avail], num - avail); |
| 58 | } |
| 59 | |
| 60 | fifo->num += num; |
| 61 | } |
| 62 | |
| 63 | uint8_t fifo8_pop(Fifo8 *fifo) |
| 64 | { |
| 65 | uint8_t ret; |
| 66 | |
| 67 | assert(fifo->num > 0); |
| 68 | ret = fifo->data[fifo->head++]; |
| 69 | fifo->head %= fifo->capacity; |
| 70 | fifo->num--; |
| 71 | return ret; |
| 72 | } |
| 73 | |
| 74 | uint8_t fifo8_peek(const Fifo8 *fifo) |
| 75 | { |
| 76 | assert(fifo->num > 0); |
| 77 | return fifo->data[fifo->head]; |
| 78 | } |
| 79 | |
| 80 | static const uint8_t *fifo8_peekpop_bufptr(Fifo8 *fifo, uint32_t max, |
| 81 | uint32_t skip, uint32_t *numptr, |
| 82 | bool do_pop) |
| 83 | { |
| 84 | uint8_t *ret; |
| 85 | uint32_t num, head; |
| 86 | |
| 87 | assert(max > 0 && max <= fifo->num); |
| 88 | assert(skip <= fifo->num); |
| 89 | head = (fifo->head + skip) % fifo->capacity; |
| 90 | num = MIN(fifo->capacity - head, max); |
| 91 | ret = &fifo->data[head]; |
| 92 | |
| 93 | if (do_pop) { |
| 94 | fifo->head = head + num; |
| 95 | fifo->head %= fifo->capacity; |
| 96 | fifo->num -= num; |
| 97 | } |
| 98 | if (numptr) { |
| 99 | *numptr = num; |
| 100 | } |
| 101 | return ret; |
| 102 | } |
| 103 | |
| 104 | const uint8_t *fifo8_peek_bufptr(Fifo8 *fifo, uint32_t max, uint32_t *numptr) |
| 105 | { |
| 106 | return fifo8_peekpop_bufptr(fifo, max, 0, numptr, false); |
| 107 | } |
| 108 | |
| 109 | const uint8_t *fifo8_pop_bufptr(Fifo8 *fifo, uint32_t max, uint32_t *numptr) |
| 110 | { |
| 111 | return fifo8_peekpop_bufptr(fifo, max, 0, numptr, true); |
| 112 | } |
| 113 | |
| 114 | static uint32_t fifo8_peekpop_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen, |
| 115 | bool do_pop) |
| 116 | { |
| 117 | const uint8_t *buf; |
| 118 | uint32_t n1, n2 = 0; |
| 119 | uint32_t len; |
| 120 | |
| 121 | if (destlen == 0) { |
| 122 | return 0; |
| 123 | } |
| 124 | |
| 125 | len = destlen; |
| 126 | buf = fifo8_peekpop_bufptr(fifo, len, 0, &n1, do_pop); |
| 127 | if (dest) { |
| 128 | memcpy(dest, buf, n1); |
| 129 | } |
| 130 | |
| 131 | /* Add FIFO wraparound if needed */ |
| 132 | len -= n1; |
| 133 | len = MIN(len, fifo8_num_used(fifo)); |
| 134 | if (len) { |
| 135 | buf = fifo8_peekpop_bufptr(fifo, len, do_pop ? 0 : n1, &n2, do_pop); |
| 136 | if (dest) { |
| 137 | memcpy(&dest[n1], buf, n2); |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | return n1 + n2; |
| 142 | } |
| 143 | |
| 144 | uint32_t fifo8_pop_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen) |
| 145 | { |
| 146 | return fifo8_peekpop_buf(fifo, dest, destlen, true); |
| 147 | } |
| 148 | |
| 149 | uint32_t fifo8_peek_buf(Fifo8 *fifo, uint8_t *dest, uint32_t destlen) |
| 150 | { |
| 151 | return fifo8_peekpop_buf(fifo, dest, destlen, false); |
| 152 | } |
| 153 | |
| 154 | void fifo8_drop(Fifo8 *fifo, uint32_t len) |
| 155 | { |
| 156 | len -= fifo8_pop_buf(fifo, NULL, len); |
| 157 | assert(len == 0); |
| 158 | } |
| 159 | |
| 160 | bool fifo8_is_empty(const Fifo8 *fifo) |
| 161 | { |
| 162 | return (fifo->num == 0); |
| 163 | } |
| 164 | |
| 165 | bool fifo8_is_full(const Fifo8 *fifo) |
| 166 | { |
| 167 | return (fifo->num == fifo->capacity); |
| 168 | } |
| 169 | |
| 170 | uint32_t fifo8_num_free(const Fifo8 *fifo) |
| 171 | { |
| 172 | return fifo->capacity - fifo->num; |
| 173 | } |
| 174 | |
| 175 | uint32_t fifo8_num_used(const Fifo8 *fifo) |
| 176 | { |
| 177 | return fifo->num; |
| 178 | } |
| 179 | |
| 180 | const VMStateDescription vmstate_fifo8 = { |
| 181 | .name = "Fifo8", |
| 182 | .version_id = 1, |
| 183 | .minimum_version_id = 1, |
| 184 | .fields = (const VMStateField[]) { |
| 185 | VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, capacity), |
| 186 | VMSTATE_UINT32(head, Fifo8), |
| 187 | VMSTATE_UINT32(num, Fifo8), |
| 188 | VMSTATE_END_OF_LIST() |
| 189 | } |
| 190 | }; |