From 237d502404632de326c9c467f8a2c691f89f25c2 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Sat, 13 Apr 2024 00:48:37 -0700
Subject: [PATCH] Util: Add prototype mAudioBuffer wrapper

---
 include/mgba-util/audio-buffer.h | 34 ++++++++++++++++++
 src/util/audio-buffer.c          | 59 ++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 include/mgba-util/audio-buffer.h
 create mode 100644 src/util/audio-buffer.c

diff --git a/include/mgba-util/audio-buffer.h b/include/mgba-util/audio-buffer.h
new file mode 100644
index 000000000..b6d760822
--- /dev/null
+++ b/include/mgba-util/audio-buffer.h
@@ -0,0 +1,34 @@
+/* Copyright (c) 2013-2024 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef M_AUDIO_BUFFER_H
+#define M_AUDIO_BUFFER_H
+
+#include <mgba-util/common.h>
+
+CXX_GUARD_START
+
+#include <mgba-util/circle-buffer.h>
+
+struct mAudioBuffer {
+	struct mCircleBuffer data;
+	unsigned channels;
+};
+
+void mAudioBufferInit(struct mAudioBuffer* buffer, size_t capacity, unsigned channels);
+void mAudioBufferDeinit(struct mAudioBuffer* buffer);
+
+size_t mAudioBufferAvailable(const struct mAudioBuffer* buffer);
+size_t mAudioBufferCapacity(const struct mAudioBuffer* buffer);
+
+void mAudioBufferClear(struct mAudioBuffer* buffer);
+int16_t mAudioBufferPeek(const struct mAudioBuffer* buffer, unsigned channel, size_t offset);
+size_t mAudioBufferDump(const struct mAudioBuffer* buffer, int16_t* samples, size_t count, size_t offset);
+size_t mAudioBufferRead(struct mAudioBuffer* buffer, int16_t* samples, size_t count);
+size_t mAudioBufferWrite(struct mAudioBuffer* buffer, const int16_t* samples, size_t count);
+
+CXX_GUARD_END
+
+#endif
diff --git a/src/util/audio-buffer.c b/src/util/audio-buffer.c
new file mode 100644
index 000000000..bb705b38c
--- /dev/null
+++ b/src/util/audio-buffer.c
@@ -0,0 +1,59 @@
+/* Copyright (c) 2013-2024 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include <mgba-util/audio-buffer.h>
+
+#include <mgba-util/memory.h>
+
+void mAudioBufferInit(struct mAudioBuffer* buffer, size_t capacity, unsigned channels) {
+	mCircleBufferInit(&buffer->data, capacity * channels * sizeof(int16_t));
+	buffer->channels = capacity;
+}
+
+void mAudioBufferDeinit(struct mAudioBuffer* buffer) {
+	mCircleBufferDeinit(&buffer->data);
+}
+
+size_t mAudioBufferAvailable(const struct mAudioBuffer* buffer) {
+	return mCircleBufferSize(&buffer->data) / (buffer->channels * sizeof(int16_t));
+}
+
+size_t mAudioBufferCapacity(const struct mAudioBuffer* buffer) {
+	return mCircleBufferCapacity(&buffer->data) / (buffer->channels * sizeof(int16_t));
+}
+
+void mAudioBufferClear(struct mAudioBuffer* buffer) {
+	mCircleBufferClear(&buffer->data);
+}
+
+int16_t mAudioBufferPeek(const struct mAudioBuffer* buffer, unsigned channel, size_t offset) {
+	int16_t sample;
+	if (!mCircleBufferDump(&buffer->data, &sample, sizeof(int16_t), (offset * buffer->channels + channel) * sizeof(int16_t))) {
+		return 0;
+	}
+	return sample;
+}
+
+size_t mAudioBufferDump(const struct mAudioBuffer* buffer, int16_t* samples, size_t count, size_t offset) {
+	return mCircleBufferDump(&buffer->data,
+	                         samples,
+	                         count * buffer->channels * sizeof(int16_t),
+	                         offset * buffer->channels * sizeof(int16_t)) /
+	       (buffer->channels * sizeof(int16_t));
+}
+
+size_t mAudioBufferRead(struct mAudioBuffer* buffer, int16_t* samples, size_t count) {
+	return mCircleBufferRead(&buffer->data, samples, count * buffer->channels * sizeof(int16_t)) /
+	       (buffer->channels * sizeof(int16_t));
+}
+
+size_t mAudioBufferWrite(struct mAudioBuffer* buffer, const int16_t* samples, size_t count) {
+	size_t free = mCircleBufferCapacity(&buffer->data) - mCircleBufferSize(&buffer->data);
+	if (count * buffer->channels * sizeof(int16_t) > free) {
+		count = free / (buffer->channels * sizeof(int16_t));
+	}
+	return mCircleBufferWrite(&buffer->data, samples, count * buffer->channels * sizeof(int16_t)) /
+	       (buffer->channels * sizeof(int16_t));
+}