488de12ed4
Previously, error_string() returned char* which is bad Serenity style and caused issues when other error handling methods were tried. As both WavLoader and (future) FLAC loader store a String internally for the error message, it makes sense to return a String reference instead.
87 lines
2.8 KiB
C++
87 lines
2.8 KiB
C++
/*
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* Copyright (c) 2018-2021, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/ByteBuffer.h>
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#include <AK/RefCounted.h>
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#include <AK/RefPtr.h>
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#include <AK/StringView.h>
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#include <LibAudio/Buffer.h>
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#include <LibCore/File.h>
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namespace Audio {
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static const String empty_string = "";
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static String no_plugin_error = "No loader plugin available";
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class LoaderPlugin {
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public:
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virtual ~LoaderPlugin() { }
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virtual bool sniff() = 0;
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virtual bool has_error() { return false; }
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virtual const String& error_string() { return empty_string; }
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virtual RefPtr<Buffer> get_more_samples(size_t max_bytes_to_read_from_input = 128 * KiB) = 0;
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virtual void reset() = 0;
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virtual void seek(const int sample_index) = 0;
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// total_samples() and loaded_samples() should be independent
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// of the number of channels.
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//
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// For example, with a three-second-long, stereo, 44.1KHz audio file:
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// num_channels() should return 2
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// sample_rate() should return 44100 (each channel is sampled at this rate)
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// total_samples() should return 132300 (sample_rate * three seconds)
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virtual int loaded_samples() = 0;
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virtual int total_samples() = 0;
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virtual u32 sample_rate() = 0;
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virtual u16 num_channels() = 0;
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virtual PcmSampleFormat pcm_format() = 0;
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virtual RefPtr<Core::File> file() = 0;
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};
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class Loader : public RefCounted<Loader> {
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public:
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static NonnullRefPtr<Loader> create(const StringView& path) { return adopt_ref(*new Loader(path)); }
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static NonnullRefPtr<Loader> create(const ByteBuffer& buffer) { return adopt_ref(*new Loader(buffer)); }
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bool has_error() const { return m_plugin ? m_plugin->has_error() : true; }
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const String& error_string() const { return m_plugin ? m_plugin->error_string() : no_plugin_error; }
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RefPtr<Buffer> get_more_samples(size_t max_bytes_to_read_from_input = 128 * KiB) const { return m_plugin ? m_plugin->get_more_samples(max_bytes_to_read_from_input) : nullptr; }
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void reset() const
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{
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if (m_plugin)
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m_plugin->reset();
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}
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void seek(const int position) const
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{
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if (m_plugin)
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m_plugin->seek(position);
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}
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int loaded_samples() const { return m_plugin ? m_plugin->loaded_samples() : 0; }
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int total_samples() const { return m_plugin ? m_plugin->total_samples() : 0; }
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u32 sample_rate() const { return m_plugin ? m_plugin->sample_rate() : 0; }
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u16 num_channels() const { return m_plugin ? m_plugin->num_channels() : 0; }
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u16 bits_per_sample() const { return m_plugin ? pcm_bits_per_sample(m_plugin->pcm_format()) : 0; }
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RefPtr<Core::File> file() const { return m_plugin ? m_plugin->file() : nullptr; }
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private:
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Loader(const StringView& path);
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Loader(const ByteBuffer& buffer);
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mutable OwnPtr<LoaderPlugin> m_plugin;
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};
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}
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