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_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 27 void fifo8_destroy(Fifo8 *fifo) 28 { 29 g_free(fifo->data); 30 } 31 32 void 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 39 void 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 58 uint8_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 69 const 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 82 void fifo8_reset(Fifo8 *fifo) 83 { 84 fifo->num = 0; 85 fifo->head = 0; 86 } 87 88 bool fifo8_is_empty(Fifo8 *fifo) 89 { 90 return (fifo->num == 0); 91 } 92 93 bool fifo8_is_full(Fifo8 *fifo) 94 { 95 return (fifo->num == fifo->capacity); 96 } 97 98 uint32_t fifo8_num_free(Fifo8 *fifo) 99 { 100 return fifo->capacity - fifo->num; 101 } 102 103 uint32_t fifo8_num_used(Fifo8 *fifo) 104 { 105 return fifo->num; 106 } 107 108 const VMStateDescription vmstate_fifo8 = { 109 .name = "Fifo8", 110 .version_id = 1, 111 .minimum_version_id = 1, 112 .fields = (const 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