acrn-hypervisor/tools/acrntrace/sbuf.c

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/*
* Copyright (C) 2018 Intel Corporation. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <asm/errno.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <stdbool.h>
#include "sbuf.h"
static inline bool sbuf_is_empty(shared_buf_t *sbuf)
{
return (sbuf->head == sbuf->tail);
}
static inline uint32_t sbuf_next_ptr(uint32_t pos,
uint32_t span, uint32_t scope)
{
pos += span;
pos = (pos >= scope) ? (pos - scope) : pos;
return pos;
}
int sbuf_get(shared_buf_t *sbuf, uint8_t *data)
{
const void *from;
if ((sbuf == NULL) || (data == NULL))
return -EINVAL;
if (sbuf_is_empty(sbuf)) {
/* no data available */
return 0;
}
from = (void *)sbuf + SBUF_HEAD_SIZE + sbuf->head;
memcpy(data, from, sbuf->ele_size);
sbuf->head = sbuf_next_ptr(sbuf->head, sbuf->ele_size, sbuf->size);
return sbuf->ele_size;
}
int sbuf_write(int fd, shared_buf_t *sbuf)
{
const void *start;
int written;
if (sbuf == NULL)
return -EINVAL;
if (sbuf_is_empty(sbuf)) {
return 0;
}
start = (void *)sbuf + SBUF_HEAD_SIZE + sbuf->head;
written = write(fd, start, sbuf->ele_size);
if ( written != sbuf->ele_size) {
printf("Failed to write. Expect written size %d, returned %d\n",
sbuf->ele_size, written);
return -1;
}
sbuf->head = sbuf_next_ptr(sbuf->head, sbuf->ele_size, sbuf->size);
return sbuf->ele_size;
}
int sbuf_clear_buffered(shared_buf_t *sbuf)
{
if (sbuf == NULL)
return -EINVAL;
sbuf->head = sbuf->tail;
return 0;
}