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 void 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 61 uint8_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 74 const 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 89 void fifo8_reset(Fifo8 *fifo) 90 { 91 fifo->num = 0; 92 fifo->head = 0; 93 } 94 95 bool fifo8_is_empty(Fifo8 *fifo) 96 { 97 return (fifo->num == 0); 98 } 99 100 bool fifo8_is_full(Fifo8 *fifo) 101 { 102 return (fifo->num == fifo->capacity); 103 } 104 105 uint32_t fifo8_num_free(Fifo8 *fifo) 106 { 107 return fifo->capacity - fifo->num; 108 } 109 110 uint32_t fifo8_num_used(Fifo8 *fifo) 111 { 112 return fifo->num; 113 } 114 115 const 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, 0, capacity), 121 VMSTATE_UINT32(head, Fifo8), 122 VMSTATE_UINT32(num, Fifo8), 123 VMSTATE_END_OF_LIST() 124 } 125 }; 126