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126 lines
2.1 KiB
126 lines
2.1 KiB
#include <stdlib.h>
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#include <stdint.h>
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#include <stddef.h>
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#include <assert.h>
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#include <string.h>
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#include "circ_buff.h"
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// Defines the circular buffer structure
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struct circ_buf_t {
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char** buffer;
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size_t head;
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size_t tail;
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size_t max; // of the buffer
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bool full;
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};
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// Private Functions
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static void advance_pointer(cbuf_handle_t cbuf) {
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assert(cbuf);
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if(cbuf->full) {
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cbuf->tail = (cbuf->tail + 1) % cbuf->max;
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}
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cbuf->head = (cbuf->head + 1) % cbuf->max;
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// We mark full because we will advance tail on the next time around
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cbuf->full = (cbuf->head == cbuf->tail);
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}
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static void retreat_pointer(cbuf_handle_t cbuf) {
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assert(cbuf);
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cbuf->full = false;
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cbuf->tail = (cbuf->tail + 1) % cbuf->max;
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}
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// APIs
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cbuf_handle_t circ_buf_init(char** buffer, size_t size) {
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assert(buffer && size);
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cbuf_handle_t cbuf = malloc(sizeof(circ_buf_t));
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assert(cbuf);
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cbuf->buffer = buffer;
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cbuf->max = size;
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circ_buf_reset(cbuf);
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assert(circ_buf_empty(cbuf));
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return cbuf;
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}
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void circ_buf_free(cbuf_handle_t cbuf) {
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assert(cbuf);
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free(cbuf);
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}
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void circ_buf_reset(cbuf_handle_t cbuf) {
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assert(cbuf);
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cbuf->head = 0;
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cbuf->tail = 0;
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cbuf->full = false;
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}
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size_t circ_buf_size(cbuf_handle_t cbuf) {
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assert(cbuf);
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size_t size = cbuf->max;
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if(!cbuf->full) {
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if(cbuf->head >= cbuf->tail) {
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size = (cbuf->head - cbuf->tail);
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}
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else {
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size = (cbuf->max + cbuf->head - cbuf->tail);
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}
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}
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return size;
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}
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size_t circ_buf_capacity(cbuf_handle_t cbuf) {
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assert(cbuf);
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return cbuf->max;
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}
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void circ_buf_put(cbuf_handle_t cbuf, char* data) {
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assert(cbuf && cbuf->buffer);
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strcpy(cbuf->buffer[cbuf->head], data);
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advance_pointer(cbuf);
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}
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int circ_buf_get(cbuf_handle_t cbuf, char* data) {
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assert(cbuf && data && cbuf->buffer);
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int r = -1;
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if(!circ_buf_empty(cbuf)) {
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strcpy(data, cbuf->buffer[cbuf->tail]);
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retreat_pointer(cbuf);
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r = 0;
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}
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return r;
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}
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bool circ_buf_empty(cbuf_handle_t cbuf) {
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assert(cbuf);
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return (!cbuf->full && (cbuf->head == cbuf->tail));
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}
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bool circ_buf_full(cbuf_handle_t cbuf) {
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assert(cbuf);
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return cbuf->full;
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}
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