/*
* 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 .
*/
#define MIN(x, y) ((x < y) ? x : y)
#include
#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;
}