95 lines
2.2 KiB
C
95 lines
2.2 KiB
C
/* ring_buffer.c: Simple ring buffer API */
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/*
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* Copyright (c) 2015 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <misc/ring_buffer.h>
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/**
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* Internal data structure for a buffer header.
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*
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* We want all of this to fit in a single uint32_t. Every item stored in the
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* ring buffer will be one of these headers plus any extra data supplied
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*/
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struct ring_element {
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uint32_t type :16; /**< Application-specific */
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uint32_t length :8; /**< length in 32-bit chunks */
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uint32_t value :8; /**< Room for small integral values */
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};
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int sys_ring_buf_put(struct ring_buf *buf, uint16_t type, uint8_t value,
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uint32_t *data, uint8_t size32)
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{
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uint32_t i, space, index, rc;
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space = sys_ring_buf_space_get(buf);
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if (space >= (size32 + 1)) {
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struct ring_element *header =
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(struct ring_element *)&buf->buf[buf->tail];
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header->type = type;
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header->length = size32;
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header->value = value;
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if (likely(buf->mask)) {
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for (i = 0; i < size32; ++i) {
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index = (i + buf->tail + 1) & buf->mask;
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buf->buf[index] = data[i];
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}
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buf->tail = (buf->tail + size32 + 1) & buf->mask;
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} else {
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for (i = 0; i < size32; ++i) {
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index = (i + buf->tail + 1) % buf->size;
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buf->buf[index] = data[i];
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}
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buf->tail = (buf->tail + size32 + 1) % buf->size;
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}
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rc = 0;
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} else {
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buf->dropped_put_count++;
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rc = -EMSGSIZE;
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}
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return rc;
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}
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int sys_ring_buf_get(struct ring_buf *buf, uint16_t *type, uint8_t *value,
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uint32_t *data, uint8_t *size32)
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{
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struct ring_element *header;
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uint32_t i, index;
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if (sys_ring_buf_is_empty(buf)) {
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return -EAGAIN;
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}
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header = (struct ring_element *) &buf->buf[buf->head];
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if (header->length > *size32) {
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*size32 = header->length;
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return -EMSGSIZE;
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}
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*size32 = header->length;
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*type = header->type;
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*value = header->value;
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if (likely(buf->mask)) {
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for (i = 0; i < header->length; ++i) {
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index = (i + buf->head + 1) & buf->mask;
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data[i] = buf->buf[index];
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}
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buf->head = (buf->head + header->length + 1) & buf->mask;
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} else {
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for (i = 0; i < header->length; ++i) {
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index = (i + buf->head + 1) % buf->size;
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data[i] = buf->buf[index];
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}
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buf->head = (buf->head + header->length + 1) % buf->size;
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}
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return 0;
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}
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