Add ringbuffer data structure

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Midgard 2020-01-29 14:45:48 +01:00 committed by redfast00
parent 05c8516217
commit 69c9b2c9ca
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85
kernel/util/ringbuffer.c Normal file
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#ifndef RINGBUFFER_C
#define RINGBUFFER_C
#include <stdbool.h>
#include "../alloc.c"
/*
* Data layout: head
* [ 4, undef, undef, 1, 2, 3 ] (1 is first added etc.)
* So enqueue adds after 4 and dequeue removes 1.
*/
struct ringbuffer {
int head;
int size;
void** buffer;
int buffer_n;
};
void rbfr_clear(struct ringbuffer* this) {
this->size = 0;
this->head = 0;
}
struct ringbuffer* rbfr_create(const int capacity) {
struct ringbuffer* const this = alloc(sizeof (struct ringbuffer));
this->buffer = alloc(capacity * sizeof (void*));
this->buffer_n = capacity;
rbfr_clear(this);
return this;
}
void rbfr_destroy(struct ringbuffer* this) {
free(this->buffer);
free(this);
}
int rbfr_size(const struct ringbuffer* this) {
return this->size;
}
int rbfr_capacity(const struct ringbuffer* this) {
return this->buffer_n;
}
void rbfr_enqueue(struct ringbuffer* this, void* element) {
if (this->buffer_n == 0) {
return;
}
int index = this->head + this->size;
if (index >= this->buffer_n) {
index -= this->buffer_n;
}
this->buffer[index] = element;
if (this->size < this->buffer_n) {
this->size++;
} else {
this->head++;
}
return;
}
bool rbfr_peek(const struct ringbuffer* this, void** element) {
if (this->size == 0) {
return false;
}
*element = this->buffer[this->head];
return true;
}
bool rbfr_dequeue(struct ringbuffer* this, void** element) {
if (!rbfr_peek(this, element)) {
return false;
}
this->size--;
this->head++;
if (this->head >= this->buffer_n) {
this->head = 0;
}
return true;
}
#endif // RINGBUFFER_C