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 if (fifo->num == fifo->capacity) { 35 abort(); 36 } 37 fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data; 38 fifo->num++; 39 } 40 41 void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num) 42 { 43 uint32_t start, avail; 44 45 if (fifo->num + num > fifo->capacity) { 46 abort(); 47 } 48 49 start = (fifo->head + fifo->num) % fifo->capacity; 50 51 if (start + num <= fifo->capacity) { 52 memcpy(&fifo->data[start], data, num); 53 } else { 54 avail = fifo->capacity - start; 55 memcpy(&fifo->data[start], data, avail); 56 memcpy(&fifo->data[0], &data[avail], num - avail); 57 } 58 59 fifo->num += num; 60 } 61 62 uint8_t fifo8_pop(Fifo8 *fifo) 63 { 64 uint8_t ret; 65 66 if (fifo->num == 0) { 67 abort(); 68 } 69 ret = fifo->data[fifo->head++]; 70 fifo->head %= fifo->capacity; 71 fifo->num--; 72 return ret; 73 } 74 75 const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num) 76 { 77 uint8_t *ret; 78 79 if (max == 0 || max > fifo->num) { 80 abort(); 81 } 82 *num = MIN(fifo->capacity - fifo->head, max); 83 ret = &fifo->data[fifo->head]; 84 fifo->head += *num; 85 fifo->head %= fifo->capacity; 86 fifo->num -= *num; 87 return ret; 88 } 89 90 void fifo8_reset(Fifo8 *fifo) 91 { 92 fifo->num = 0; 93 fifo->head = 0; 94 } 95 96 bool fifo8_is_empty(Fifo8 *fifo) 97 { 98 return (fifo->num == 0); 99 } 100 101 bool fifo8_is_full(Fifo8 *fifo) 102 { 103 return (fifo->num == fifo->capacity); 104 } 105 106 uint32_t fifo8_num_free(Fifo8 *fifo) 107 { 108 return fifo->capacity - fifo->num; 109 } 110 111 uint32_t fifo8_num_used(Fifo8 *fifo) 112 { 113 return fifo->num; 114 } 115 116 const VMStateDescription vmstate_fifo8 = { 117 .name = "Fifo8", 118 .version_id = 1, 119 .minimum_version_id = 1, 120 .fields = (VMStateField[]) { 121 VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, capacity), 122 VMSTATE_UINT32(head, Fifo8), 123 VMSTATE_UINT32(num, Fifo8), 124 VMSTATE_END_OF_LIST() 125 } 126 }; 127