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/src/util/bytebuf.c

@@ -0,0 +1,75 @@
+#include "bytebuf.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "util/log.h"
+
+bool
+sc_bytebuf_init(struct sc_bytebuf *buf, size_t alloc_size) {
+    assert(alloc_size);
+    buf->data = malloc(alloc_size);
+    if (!buf->data) {
+        LOG_OOM();
+        return false;
+    }
+
+    buf->alloc_size = alloc_size;
+    buf->head = 0;
+    buf->tail = 0;
+
+    return true;
+}
+
+void
+sc_bytebuf_destroy(struct sc_bytebuf *buf) {
+    free(buf->data);
+}
+
+void
+sc_bytebuf_read(struct sc_bytebuf *buf, uint8_t *to, size_t len) {
+    assert(len);
+    assert(len <= sc_bytebuf_read_available(buf));
+    assert(buf->tail != buf->head); // the buffer could not be empty
+
+    size_t right_limit = buf->tail < buf->head ? buf->head : buf->alloc_size;
+    size_t right_len = right_limit - buf->tail;
+    if (len < right_len) {
+        right_len = len;
+    }
+    memcpy(to, buf->data + buf->tail, right_len);
+
+    if (len > right_len) {
+        memcpy(to + right_len, buf->data, len - right_len);
+    }
+
+    buf->tail = (buf->tail + len) % buf->alloc_size;
+}
+
+void
+sc_bytebuf_skip(struct sc_bytebuf *buf, size_t len) {
+    assert(len);
+    assert(len <= sc_bytebuf_read_available(buf));
+    assert(buf->tail != buf->head); // the buffer could not be empty
+
+    buf->tail = (buf->tail + len) % buf->alloc_size;
+}
+
+void
+sc_bytebuf_write(struct sc_bytebuf *buf, const uint8_t *from, size_t len) {
+    assert(len);
+    assert(len <= sc_bytebuf_write_available(buf));
+
+    size_t right_len = buf->alloc_size - buf->head;
+    if (len < right_len) {
+        right_len = len;
+    }
+    memcpy(buf->data + buf->head, from, right_len);
+
+    if (len > right_len) {
+        memcpy(buf->data, from + right_len, len - right_len);
+    }
+
+    buf->head = (buf->head + len) % buf->alloc_size;
+}