86 lines
1.5 KiB
C
86 lines
1.5 KiB
C
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#ifndef RINGBUFFER_C
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#define RINGBUFFER_C
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#include <stdbool.h>
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#include "../alloc.c"
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/*
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* Data layout: ↓head
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* [ 4, undef, undef, 1, 2, 3 ] (1 is first added etc.)
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* So enqueue adds after 4 and dequeue removes 1.
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*/
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struct ringbuffer {
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int head;
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int size;
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void** buffer;
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int buffer_n;
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};
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void rbfr_clear(struct ringbuffer* this) {
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this->size = 0;
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this->head = 0;
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}
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struct ringbuffer* rbfr_create(const int capacity) {
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struct ringbuffer* const this = alloc(sizeof (struct ringbuffer));
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this->buffer = alloc(capacity * sizeof (void*));
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this->buffer_n = capacity;
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rbfr_clear(this);
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return this;
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}
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void rbfr_destroy(struct ringbuffer* this) {
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free(this->buffer);
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free(this);
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}
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int rbfr_size(const struct ringbuffer* this) {
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return this->size;
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}
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int rbfr_capacity(const struct ringbuffer* this) {
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return this->buffer_n;
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}
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void rbfr_enqueue(struct ringbuffer* this, void* element) {
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if (this->buffer_n == 0) {
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return;
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}
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int index = this->head + this->size;
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if (index >= this->buffer_n) {
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index -= this->buffer_n;
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}
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this->buffer[index] = element;
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if (this->size < this->buffer_n) {
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this->size++;
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} else {
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this->head++;
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}
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return;
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}
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bool rbfr_peek(const struct ringbuffer* this, void** element) {
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if (this->size == 0) {
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return false;
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}
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*element = this->buffer[this->head];
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return true;
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}
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bool rbfr_dequeue(struct ringbuffer* this, void** element) {
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if (!rbfr_peek(this, element)) {
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return false;
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}
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this->size--;
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this->head++;
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if (this->head >= this->buffer_n) {
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this->head = 0;
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}
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return true;
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}
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#endif // RINGBUFFER_C
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