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- /*
- * ring.c
- *
- * Copyright (c) 2023 Thomas Buck (thomas@xythobuz.de)
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * See <http://www.gnu.org/licenses/>.
- */
-
- #define MIN(x, y) ((x < y) ? x : y)
-
- #include <string.h>
-
- #include "config.h"
- #include "ring.h"
-
- void rb_add(struct ring_buffer *rb, const void *data, size_t length) {
- for (size_t i = 0; i < length; i++) {
- memcpy(rb->buffer + rb->head * rb->el_len, data + i * rb->el_len, rb->el_len);
-
- if (rb->full && (++(rb->tail) == rb->size)) {
- rb->tail = 0;
- }
-
- if (++(rb->head) == rb->size) {
- rb->head = 0;
- }
-
- rb->full = ((rb->head) == (rb->tail));
- }
- }
-
- size_t rb_len(struct ring_buffer *rb) {
- if (rb->head == rb->tail) {
- if (rb->full) {
- return rb->size;
- } else {
- return 0;
- }
- } else if (rb->head > rb->tail) {
- return rb->head - rb->tail;
- } else {
- return rb->size - rb->tail + rb->head;
- }
- }
-
- void rb_dump(struct ring_buffer *rb, void (*write)(const void *, size_t), size_t skip) {
- if (rb_len(rb) <= skip) {
- return;
- }
-
- if (rb->head > rb->tail) {
- if ((rb->head - rb->tail) > skip) {
- write(rb->buffer + ((rb->tail + skip) * rb->el_len), rb->head - rb->tail - skip);
- }
- } else {
- if ((rb->size - rb->tail) > skip) {
- write(rb->buffer + ((rb->tail + skip) * rb->el_len), rb->size - rb->tail - skip);
- }
-
- skip -= MIN(skip, rb->size - rb->tail);
- if (rb->head > skip) {
- write(rb->buffer + (skip + rb->el_len), rb->head - skip);
- }
- }
- }
-
- void rb_move(struct ring_buffer *rb, void (*write)(const void *, size_t)) {
- rb_dump(rb, write, 0);
- rb->head = 0;
- rb->tail = 0;
- rb->full = false;
- }
-
- void rb_peek(struct ring_buffer *rb, void *buf) {
- if (rb_len(rb) == 0) {
- return;
- }
-
- memcpy(buf, rb->buffer + rb->tail * rb->el_len, rb->el_len);
- }
-
- void rb_pop(struct ring_buffer *rb, void *buf) {
- if (rb_len(rb) == 0) {
- return;
- }
-
- memcpy(buf, rb->buffer + rb->tail * rb->el_len, rb->el_len);
- rb->tail++;
- if (rb->tail >= rb->size) {
- rb->tail = 0;
- }
- }
-
- size_t rb_get(struct ring_buffer *rb, void *data, size_t length) {
- size_t count = 0;
- while ((length > 0) && (rb_len(rb) > 0)) {
- rb_pop(rb, data + count * rb->el_len);
- count++;
- length--;
- }
- return count;
- }
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