blob: 21cdab63a1f7de18361a7060c0f1ff56dfb0f1bd [file] [log] [blame]
/* ring_buffer.c: Simple ring buffer API */
/*
* Copyright (c) 2015 Intel Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <misc/ring_buffer.h>
/**
* Internal data structure for a buffer header.
*
* We want all of this to fit in a single uint32_t. Every item stored in the
* ring buffer will be one of these headers plus any extra data supplied
*/
struct ring_element {
uint32_t type :16; /**< Application-specific */
uint32_t length :8; /**< length in 32-bit chunks */
uint32_t value :8; /**< Room for small integral values */
};
int sys_ring_buf_put(struct ring_buf *buf, uint16_t type, uint8_t value,
uint32_t *data, uint8_t size32)
{
uint32_t i, space, index, rc;
space = sys_ring_buf_space_get(buf);
if (space >= (size32 + 1)) {
struct ring_element *header =
(struct ring_element *)&buf->buf[buf->tail];
header->type = type;
header->length = size32;
header->value = value;
if (likely(buf->mask)) {
for (i = 0; i < size32; ++i) {
index = (i + buf->tail + 1) & buf->mask;
buf->buf[index] = data[i];
}
buf->tail = (buf->tail + size32 + 1) & buf->mask;
} else {
for (i = 0; i < size32; ++i) {
index = (i + buf->tail + 1) % buf->size;
buf->buf[index] = data[i];
}
buf->tail = (buf->tail + size32 + 1) % buf->size;
}
rc = 0;
} else {
buf->dropped_put_count++;
rc = -EMSGSIZE;
}
return rc;
}
int sys_ring_buf_get(struct ring_buf *buf, uint16_t *type, uint8_t *value,
uint32_t *data, uint8_t *size32)
{
struct ring_element *header;
uint32_t i, index;
if (sys_ring_buf_is_empty(buf)) {
return -EAGAIN;
}
header = (struct ring_element *) &buf->buf[buf->head];
if (header->length > *size32) {
*size32 = header->length;
return -EMSGSIZE;
}
*size32 = header->length;
*type = header->type;
*value = header->value;
if (likely(buf->mask)) {
for (i = 0; i < header->length; ++i) {
index = (i + buf->head + 1) & buf->mask;
data[i] = buf->buf[index];
}
buf->head = (buf->head + header->length + 1) & buf->mask;
} else {
for (i = 0; i < header->length; ++i) {
index = (i + buf->head + 1) % buf->size;
data[i] = buf->buf[index];
}
buf->head = (buf->head + header->length + 1) % buf->size;
}
return 0;
}