audio_core: Add initial code for keeping track of audout state.

src/audio_core/stream.cpp

@@ -0,0 +1,103 @@
+// Copyright 2018 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/assert.h"
+#include "common/logging/log.h"
+#include "core/core_timing.h"
+#include "core/core_timing_util.h"
+
+#include "audio_core/stream.h"
+
+namespace AudioCore {
+
+constexpr size_t MaxAudioBufferCount{32};
+
+/// Returns the sample size for the specified audio stream format
+static size_t SampleSizeFromFormat(Stream::Format format) {
+    switch (format) {
+    case Stream::Format::Mono16:
+        return 2;
+    case Stream::Format::Stereo16:
+        return 4;
+    case Stream::Format::Multi51Channel16:
+        return 12;
+    };
+
+    LOG_CRITICAL(Audio, "Unimplemented format={}", static_cast<u32>(format));
+    UNREACHABLE();
+    return {};
+}
+
+Stream::Stream(int sample_rate, Format format, ReleaseCallback&& release_callback)
+    : sample_rate{sample_rate}, format{format}, release_callback{std::move(release_callback)} {
+    release_event = CoreTiming::RegisterEvent(
+        "Stream::Release", [this](u64 userdata, int cycles_late) { ReleaseActiveBuffer(); });
+}
+
+void Stream::Play() {
+    state = State::Playing;
+    PlayNextBuffer();
+}
+
+void Stream::Stop() {
+    ASSERT_MSG(false, "Unimplemented");
+}
+
+s64 Stream::GetBufferReleaseCycles(const Buffer& buffer) const {
+    const size_t num_samples{buffer.GetData().size() / SampleSizeFromFormat(format)};
+    return CoreTiming::usToCycles((static_cast<u64>(num_samples) * 1000000) / sample_rate);
+}
+
+void Stream::PlayNextBuffer() {
+    if (!IsPlaying()) {
+        // Ensure we are in playing state before playing the next buffer
+        return;
+    }
+
+    if (active_buffer) {
+        // Do not queue a new buffer if we are already playing a buffer
+        return;
+    }
+
+    if (queued_buffers.empty()) {
+        // No queued buffers - we are effectively paused
+        return;
+    }
+
+    active_buffer = queued_buffers.front();
+    queued_buffers.pop();
+
+    CoreTiming::ScheduleEventThreadsafe(GetBufferReleaseCycles(*active_buffer), release_event, {});
+}
+
+void Stream::ReleaseActiveBuffer() {
+    released_buffers.push(std::move(active_buffer));
+    release_callback();
+    PlayNextBuffer();
+}
+
+bool Stream::QueueBuffer(BufferPtr&& buffer) {
+    if (queued_buffers.size() < MaxAudioBufferCount) {
+        queued_buffers.push(std::move(buffer));
+        PlayNextBuffer();
+        return true;
+    }
+    return false;
+}
+
+bool Stream::ContainsBuffer(Buffer::Tag tag) const {
+    ASSERT_MSG(false, "Unimplemented");
+    return {};
+}
+
+std::vector<Buffer::Tag> Stream::GetTagsAndReleaseBuffers(size_t max_count) {
+    std::vector<Buffer::Tag> tags;
+    for (size_t count = 0; count < max_count && !released_buffers.empty(); ++count) {
+        tags.push_back(released_buffers.front()->GetTag());
+        released_buffers.pop();
+    }
+    return tags;
+}
+
+} // namespace AudioCore