Introduce bytebuf util

Add a ring-buffer for bytes. It will be useful for audio buffering.

PR #3757 <https://github.com/Genymobile/scrcpy/pull/3757>

app/tests/test_bytebuf.c

@@ -0,0 +1,82 @@
+#include "common.h"
+
+#include <assert.h>
+#include <string.h>
+
+#include "util/bytebuf.h"
+
+void test_bytebuf_simple(void) {
+    struct sc_bytebuf buf;
+    uint8_t data[20];
+
+    bool ok = sc_bytebuf_init(&buf, 20);
+    assert(ok);
+
+    sc_bytebuf_write(&buf, (uint8_t *) "hello", sizeof("hello") - 1);
+    assert(sc_bytebuf_read_available(&buf) == 5);
+
+    sc_bytebuf_read(&buf, data, 4);
+    assert(!strncmp((char *) data, "hell", 4));
+
+    sc_bytebuf_write(&buf, (uint8_t *) " world", sizeof(" world") - 1);
+    assert(sc_bytebuf_read_available(&buf) == 7);
+
+    sc_bytebuf_write(&buf, (uint8_t *) "!", 1);
+    assert(sc_bytebuf_read_available(&buf) == 8);
+
+    sc_bytebuf_read(&buf, &data[4], 8);
+    assert(sc_bytebuf_read_available(&buf) == 0);
+
+    data[12] = '\0';
+    assert(!strcmp((char *) data, "hello world!"));
+    assert(sc_bytebuf_read_available(&buf) == 0);
+
+    sc_bytebuf_destroy(&buf);
+}
+
+void test_bytebuf_boundaries(void) {
+    struct sc_bytebuf buf;
+    uint8_t data[20];
+
+    bool ok = sc_bytebuf_init(&buf, 20);
+    assert(ok);
+
+    sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
+    assert(sc_bytebuf_read_available(&buf) == 6);
+
+    sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
+    assert(sc_bytebuf_read_available(&buf) == 12);
+
+    sc_bytebuf_write(&buf, (uint8_t *) "hello ", sizeof("hello ") - 1);
+    assert(sc_bytebuf_read_available(&buf) == 18);
+
+    sc_bytebuf_read(&buf, data, 9);
+    assert(!strncmp((char *) data, "hello hel", 9));
+    assert(sc_bytebuf_read_available(&buf) == 9);
+
+    sc_bytebuf_write(&buf, (uint8_t *) "world", sizeof("world") - 1);
+    assert(sc_bytebuf_read_available(&buf) == 14);
+
+    sc_bytebuf_write(&buf, (uint8_t *) "!", 1);
+    assert(sc_bytebuf_read_available(&buf) == 15);
+
+    sc_bytebuf_skip(&buf, 3);
+    assert(sc_bytebuf_read_available(&buf) == 12);
+
+    sc_bytebuf_read(&buf, data, 12);
+    data[12] = '\0';
+    assert(!strcmp((char *) data, "hello world!"));
+    assert(sc_bytebuf_read_available(&buf) == 0);
+
+    sc_bytebuf_destroy(&buf);
+}
+
+int main(int argc, char *argv[]) {
+    (void) argc;
+    (void) argv;
+
+    test_bytebuf_simple();
+    test_bytebuf_boundaries();
+
+    return 0;
+}