blob: 6c9b149c29bd3250641a286b625e6f2327ab48f1 [file] [log] [blame]
/* ring_buffer.c: Simple ring buffer API */
/*
* Copyright (c) 2015 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <ring_buffer.h>
#include <string.h>
/**
* Internal data structure for a buffer header.
*
* We want all of this to fit in a single u32_t. Every item stored in the
* ring buffer will be one of these headers plus any extra data supplied
*/
struct ring_element {
u32_t type :16; /**< Application-specific */
u32_t length :8; /**< length in 32-bit chunks */
u32_t value :8; /**< Room for small integral values */
};
int ring_buf_item_put(struct ring_buf *buf, u16_t type, u8_t value,
u32_t *data, u8_t size32)
{
u32_t i, space, index, rc;
space = ring_buf_space_get(buf);
if (space >= (size32 + 1)) {
struct ring_element *header =
(struct ring_element *)&buf->buf.buf32[buf->tail];
header->type = type;
header->length = size32;
header->value = value;
if (likely(buf->mask)) {
for (i = 0U; i < size32; ++i) {
index = (i + buf->tail + 1) & buf->mask;
buf->buf.buf32[index] = data[i];
}
buf->tail = (buf->tail + size32 + 1) & buf->mask;
} else {
for (i = 0U; i < size32; ++i) {
index = (i + buf->tail + 1) % buf->size;
buf->buf.buf32[index] = data[i];
}
buf->tail = (buf->tail + size32 + 1) % buf->size;
}
rc = 0U;
} else {
buf->misc.item_mode.dropped_put_count++;
rc = -EMSGSIZE;
}
return rc;
}
int ring_buf_item_get(struct ring_buf *buf, u16_t *type, u8_t *value,
u32_t *data, u8_t *size32)
{
struct ring_element *header;
u32_t i, index;
if (ring_buf_is_empty(buf)) {
return -EAGAIN;
}
header = (struct ring_element *) &buf->buf.buf32[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 = 0U; i < header->length; ++i) {
index = (i + buf->head + 1) & buf->mask;
data[i] = buf->buf.buf32[index];
}
buf->head = (buf->head + header->length + 1) & buf->mask;
} else {
for (i = 0U; i < header->length; ++i) {
index = (i + buf->head + 1) % buf->size;
data[i] = buf->buf.buf32[index];
}
buf->head = (buf->head + header->length + 1) % buf->size;
}
return 0;
}
/** @brief Wraps index if it exceeds the limit.
*
* @param val Value
* @param max Max.
*
* @return value % max.
*/
static inline u32_t wrap(u32_t val, u32_t max)
{
return val >= max ? (val - max) : val;
}
u32_t ring_buf_put_claim(struct ring_buf *buf, u8_t **data, u32_t size)
{
u32_t space, trail_size, allocated;
space = z_ring_buf_custom_space_get(buf->size, buf->head,
buf->misc.byte_mode.tmp_tail);
/* Limit requested size to available size. */
size = min(size, space);
trail_size = buf->size - buf->misc.byte_mode.tmp_tail;
/* Limit allocated size to trail size. */
allocated = min(trail_size, size);
*data = &buf->buf.buf8[buf->misc.byte_mode.tmp_tail];
buf->misc.byte_mode.tmp_tail =
wrap(buf->misc.byte_mode.tmp_tail + allocated, buf->size);
return allocated;
}
int ring_buf_put_finish(struct ring_buf *buf, u32_t size)
{
if (size > ring_buf_space_get(buf)) {
return -EINVAL;
}
buf->tail = wrap(buf->tail + size, buf->size);
buf->misc.byte_mode.tmp_tail = buf->tail;
return 0;
}
u32_t ring_buf_put(struct ring_buf *buf, const u8_t *data, u32_t size)
{
u8_t *dst;
u32_t partial_size;
u32_t total_size = 0U;
do {
partial_size = ring_buf_put_claim(buf, &dst, size);
memcpy(dst, data, partial_size);
total_size += partial_size;
size -= partial_size;
data += partial_size;
} while (size && partial_size);
ring_buf_put_finish(buf, total_size);
return total_size;
}
u32_t ring_buf_get_claim(struct ring_buf *buf, u8_t **data, u32_t size)
{
u32_t space, granted_size, trail_size;
space = (buf->size - 1) -
z_ring_buf_custom_space_get(buf->size,
buf->misc.byte_mode.tmp_head,
buf->tail);
trail_size = buf->size - buf->misc.byte_mode.tmp_head;
/* Limit requested size to available size. */
granted_size = min(size, space);
/* Limit allocated size to trail size. */
granted_size = min(trail_size, granted_size);
*data = &buf->buf.buf8[buf->misc.byte_mode.tmp_head];
buf->misc.byte_mode.tmp_head =
wrap(buf->misc.byte_mode.tmp_head + granted_size, buf->size);
return granted_size;
}
int ring_buf_get_finish(struct ring_buf *buf, u32_t size)
{
u32_t allocated = (buf->size - 1) - ring_buf_space_get(buf);
if (size > allocated) {
return -EINVAL;
}
buf->head = wrap(buf->head + size, buf->size);
buf->misc.byte_mode.tmp_head = buf->head;
return 0;
}
u32_t ring_buf_get(struct ring_buf *buf, u8_t *data, u32_t size)
{
u8_t *src;
u32_t partial_size;
u32_t total_size = 0U;
do {
partial_size = ring_buf_get_claim(buf, &src, size);
memcpy(data, src, partial_size);
total_size += partial_size;
size -= partial_size;
data += partial_size;
} while (size && partial_size);
ring_buf_get_finish(buf, total_size);
return total_size;
}