Add audio sample ring-buffer

Add a thin wrapper around bytebuf to handle samples instead of bytes.
This simplifies the audio player, which mostly handles samples.

app/src/util/audiobuf.h

@@ -0,0 +1,94 @@
+#ifndef SC_AUDIOBUF_H
+#define SC_AUDIOBUF_H
+
+#include "common.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "util/bytebuf.h"
+
+/**
+ * Wrapper around bytebuf to read and write samples
+ *
+ * Each sample takes sample_size bytes.
+ */
+struct sc_audiobuf {
+    struct sc_bytebuf buf;
+    size_t sample_size;
+};
+
+static inline uint32_t
+sc_audiobuf_to_samples(struct sc_audiobuf *buf, size_t bytes) {
+    assert(bytes % buf->sample_size == 0);
+    return bytes / buf->sample_size;
+}
+
+static inline size_t
+sc_audiobuf_to_bytes(struct sc_audiobuf *buf, uint32_t samples) {
+    return samples * buf->sample_size;
+}
+
+static inline bool
+sc_audiobuf_init(struct sc_audiobuf *buf, size_t sample_size,
+                 uint32_t capacity) {
+    buf->sample_size = sample_size;
+    return sc_bytebuf_init(&buf->buf, capacity * sample_size + 1);
+}
+
+static inline void
+sc_audiobuf_read(struct sc_audiobuf *buf, uint8_t *to, uint32_t samples) {
+    size_t bytes = sc_audiobuf_to_bytes(buf, samples);
+    sc_bytebuf_read(&buf->buf, to, bytes);
+}
+
+static inline void
+sc_audiobuf_skip(struct sc_audiobuf *buf, uint32_t samples) {
+    size_t bytes = sc_audiobuf_to_bytes(buf, samples);
+    sc_bytebuf_skip(&buf->buf, bytes);
+}
+
+static inline void
+sc_audiobuf_write(struct sc_audiobuf *buf, const uint8_t *from,
+                  uint32_t samples) {
+    size_t bytes = sc_audiobuf_to_bytes(buf, samples);
+    sc_bytebuf_write(&buf->buf, from, bytes);
+}
+
+static inline void
+sc_audiobuf_prepare_write(struct sc_audiobuf *buf, const uint8_t *from,
+                          uint32_t samples) {
+    size_t bytes = sc_audiobuf_to_bytes(buf, samples);
+    sc_bytebuf_prepare_write(&buf->buf, from, bytes);
+}
+
+static inline void
+sc_audiobuf_commit_write(struct sc_audiobuf *buf, uint32_t samples) {
+    size_t bytes = sc_audiobuf_to_bytes(buf, samples);
+    sc_bytebuf_commit_write(&buf->buf, bytes);
+}
+
+static inline uint32_t
+sc_audiobuf_read_available(struct sc_audiobuf *buf) {
+    size_t bytes = sc_bytebuf_read_available(&buf->buf);
+    return sc_audiobuf_to_samples(buf, bytes);
+}
+
+static inline uint32_t
+sc_audiobuf_write_available(struct sc_audiobuf *buf) {
+    size_t bytes = sc_bytebuf_write_available(&buf->buf);
+    return sc_audiobuf_to_samples(buf, bytes);
+}
+
+static inline uint32_t
+sc_audiobuf_capacity(struct sc_audiobuf *buf) {
+    size_t bytes = sc_bytebuf_capacity(&buf->buf);
+    return sc_audiobuf_to_samples(buf, bytes);
+}
+
+static inline void
+sc_audiobuf_destroy(struct sc_audiobuf *buf) {
+    sc_bytebuf_destroy(&buf->buf);
+}
+
+#endif