Add generic circular buffer
Add a circular buffer implementation, to factorize multiple specific queues implementation.
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3 changed files with 126 additions and 0 deletions
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@ -154,6 +154,9 @@ executable('scrcpy', src,
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### TESTS
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tests = [
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['test_cbuf', [
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'tests/test_cbuf.c',
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]],
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['test_control_event_queue', [
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'tests/test_control_event_queue.c',
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'src/control_event.c'
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50
app/src/cbuf.h
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50
app/src/cbuf.h
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// generic circular buffer (bounded queue) implementation
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#ifndef CBUF_H
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#define CBUF_H
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#include <stdbool.h>
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#include <unistd.h>
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// To define a circular buffer type of 20 ints:
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// typedef CBUF(int, 20) my_cbuf_t;
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//
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// data has length CAP + 1 to distinguish empty vs full.
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#define CBUF(TYPE, CAP) { \
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TYPE data[(CAP) + 1]; \
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size_t head; \
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size_t tail; \
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}
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#define cbuf_size_(PCBUF) \
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(sizeof((PCBUF)->data) / sizeof(*(PCBUF)->data))
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#define cbuf_is_empty(PCBUF) \
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((PCBUF)->head == (PCBUF)->tail)
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#define cbuf_is_full(PCBUF) \
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(((PCBUF)->head + 1) % cbuf_size_(PCBUF) == (PCBUF)->tail)
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#define cbuf_init(PCBUF) \
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(void) ((PCBUF)->head = (PCBUF)->tail = 0)
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#define cbuf_push(PCBUF, ITEM) \
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({ \
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bool ok = !cbuf_is_full(PCBUF); \
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if (ok) { \
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(PCBUF)->data[(PCBUF)->head] = (ITEM); \
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(PCBUF)->head = ((PCBUF)->head + 1) % cbuf_size_(PCBUF); \
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} \
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ok; \
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}) \
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#define cbuf_take(PCBUF, PITEM) \
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({ \
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bool ok = !cbuf_is_empty(PCBUF); \
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if (ok) { \
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*(PITEM) = (PCBUF)->data[(PCBUF)->tail]; \
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(PCBUF)->tail = ((PCBUF)->tail + 1) % cbuf_size_(PCBUF); \
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} \
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ok; \
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})
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#endif
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73
app/tests/test_cbuf.c
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73
app/tests/test_cbuf.c
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#include <assert.h>
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#include <string.h>
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#include "cbuf.h"
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struct int_queue CBUF(int, 32);
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static void test_cbuf_empty(void) {
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struct int_queue queue;
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cbuf_init(&queue);
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assert(cbuf_is_empty(&queue));
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bool push_ok = cbuf_push(&queue, 42);
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assert(push_ok);
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assert(!cbuf_is_empty(&queue));
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int item;
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bool take_ok = cbuf_take(&queue, &item);
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assert(take_ok);
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assert(cbuf_is_empty(&queue));
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bool take_empty_ok = cbuf_take(&queue, &item);
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assert(!take_empty_ok); // the queue is empty
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}
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static void test_cbuf_full(void) {
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struct int_queue queue;
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cbuf_init(&queue);
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assert(!cbuf_is_full(&queue));
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// fill the queue
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for (int i = 0; i < 32; ++i) {
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bool ok = cbuf_push(&queue, i);
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assert(ok);
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}
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bool ok = cbuf_push(&queue, 42);
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assert(!ok); // the queue if full
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int item;
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bool take_ok = cbuf_take(&queue, &item);
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assert(take_ok);
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assert(!cbuf_is_full(&queue));
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}
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static void test_cbuf_push_take(void) {
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struct int_queue queue;
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cbuf_init(&queue);
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bool push1_ok = cbuf_push(&queue, 42);
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assert(push1_ok);
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bool push2_ok = cbuf_push(&queue, 35);
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assert(push2_ok);
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int item;
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bool take1_ok = cbuf_take(&queue, &item);
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assert(take1_ok);
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assert(item == 42);
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bool take2_ok = cbuf_take(&queue, &item);
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assert(take2_ok);
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assert(item == 35);
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}
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int main(void) {
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test_cbuf_empty();
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test_cbuf_full();
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test_cbuf_push_take();
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return 0;
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}
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