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/*
* Copyright (c) 2018-2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/FixedArray.h>
#include <AK/NonnullOwnPtr.h>
#include <AK/NonnullRefPtr.h>
#include <AK/RefCounted.h>
#include <AK/RefPtr.h>
#include <AK/Result.h>
#include <AK/Span.h>
#include <AK/Stream.h>
#include <AK/StringView.h>
#include <AK/Try.h>
#include <LibAudio/GenericTypes.h>
#include <LibAudio/LoaderError.h>
#include <LibAudio/Metadata.h>
#include <LibAudio/Sample.h>
#include <LibAudio/SampleFormats.h>
namespace Audio {
static constexpr StringView no_plugin_error = "No loader plugin available"sv;
// Experimentally determined to be a decent buffer size on i686:
// 4K (the default) is slightly worse, and 64K is much worse.
// At sufficiently large buffer sizes, the advantage of infrequent read() calls is outweighed by the memmove() overhead.
// There was no intensive fine-tuning done to determine this value, so improvements may definitely be possible.
constexpr size_t const loader_buffer_size = 8 * KiB;
// Two seek points should ideally not be farther apart than this.
// This variable is a heuristic for seek table-constructing loaders.
constexpr u64 const maximum_seekpoint_distance_ms = 1000;
// Seeking should be at least as precise as this.
// That means: The actual achieved seek position must not be more than this amount of time before the requested seek position.
constexpr u64 const seek_tolerance_ms = 5000;
using LoaderSamples = ErrorOr<FixedArray<Sample>, LoaderError>;
using MaybeLoaderError = ErrorOr<void, LoaderError>;
class LoaderPlugin {
public:
explicit LoaderPlugin(NonnullOwnPtr<SeekableStream> stream);
virtual ~LoaderPlugin() = default;
// Load as many audio chunks as necessary to get up to the required samples.
// A chunk can be anything that is convenient for the plugin to load in one go without requiring to move samples around different buffers.
// For example: A FLAC, MP3 or QOA frame.
// The chunks are returned in a vector, so the loader can simply add chunks until the requested sample amount is reached.
// The sample count MAY be surpassed, but only as little as possible. It CAN be undershot when the end of the stream is reached.
// If the loader has no chunking limitations (e.g. WAV), it may return a single exact-sized chunk.
virtual ErrorOr<Vector<FixedArray<Sample>>, LoaderError> load_chunks(size_t samples_to_read_from_input) = 0;
virtual MaybeLoaderError reset() = 0;
virtual MaybeLoaderError seek(int const sample_index) = 0;
// total_samples() and loaded_samples() should be independent
// of the number of channels.
//
// For example, with a three-second-long, stereo, 44.1KHz audio file:
// num_channels() should return 2
// sample_rate() should return 44100 (each channel is sampled at this rate)
// total_samples() should return 132300 (sample_rate * three seconds)
virtual int loaded_samples() = 0;
virtual int total_samples() = 0;
virtual u32 sample_rate() = 0;
virtual u16 num_channels() = 0;
// Human-readable name of the file format, of the form <full abbreviation> (.<ending>)
virtual DeprecatedString format_name() = 0;
virtual PcmSampleFormat pcm_format() = 0;
Metadata const& metadata() const { return m_metadata; }
Vector<PictureData> const& pictures() const { return m_pictures; };
protected:
NonnullOwnPtr<SeekableStream> m_stream;
Vector<PictureData> m_pictures;
Metadata m_metadata;
};
class Loader : public RefCounted<Loader> {
public:
static Result<NonnullRefPtr<Loader>, LoaderError> create(StringView path) { return adopt_ref(*new Loader(TRY(create_plugin(path)))); }
static Result<NonnullRefPtr<Loader>, LoaderError> create(Bytes buffer) { return adopt_ref(*new Loader(TRY(create_plugin(buffer)))); }
// Will only read less samples if we're at the end of the stream.
LoaderSamples get_more_samples(size_t samples_to_read_from_input = 128 * KiB);
MaybeLoaderError reset() const { return m_plugin->reset(); }
MaybeLoaderError seek(int const position) const
{
m_buffer.clear_with_capacity();
return m_plugin->seek(position);
}
int loaded_samples() const { return m_plugin->loaded_samples(); }
int total_samples() const { return m_plugin->total_samples(); }
u32 sample_rate() const { return m_plugin->sample_rate(); }
u16 num_channels() const { return m_plugin->num_channels(); }
DeprecatedString format_name() const { return m_plugin->format_name(); }
u16 bits_per_sample() const { return pcm_bits_per_sample(m_plugin->pcm_format()); }
Metadata const& metadata() const { return m_plugin->metadata(); }
Vector<PictureData> const& pictures() const { return m_plugin->pictures(); };
private:
static Result<NonnullOwnPtr<LoaderPlugin>, LoaderError> create_plugin(StringView path);
static Result<NonnullOwnPtr<LoaderPlugin>, LoaderError> create_plugin(Bytes buffer);
explicit Loader(NonnullOwnPtr<LoaderPlugin>);
mutable NonnullOwnPtr<LoaderPlugin> m_plugin;
mutable Vector<Sample, loader_buffer_size> m_buffer;
};
}
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