serenity/Libraries/LibAudio/ABuffer.h

#pragma once

#include <AK/RefCounted.h>
#include <AK/ByteBuffer.h>
#include <AK/Types.h>
#include <AK/Vector.h>
#include <LibC/SharedBuffer.h>

// A single sample in an audio buffer.
// Values are floating point, and should range from -1.0 to +1.0
struct ASample {
    ASample()
        : left(0)
        , right(0)
    {}

    // For mono
    ASample(float left)
        : left(left)
        , right(left)
    {}

    // For stereo
    ASample(float left, float right)
        : left(left)
        , right(right)
    {}

    void clip()
    {
        if (left > 1)
            left = 1;
        else if (left < -1)
            left = -1;

        if (right > 1)
            right = 1;
        else if (right < -1)
            right = -1;
    }

    void scale(int percent)
    {
        float pct = (float)percent / 100.0;
        left *= pct;
        right *= pct;
    }

    ASample& operator+=(const ASample& other)
    {
        left += other.left;
        right += other.right;
        return *this;
    }

    float left;
    float right;
};

// A buffer of audio samples, normalized to 44100hz.
class ABuffer : public RefCounted<ABuffer> {
public:
    static RefPtr<ABuffer> from_pcm_data(ByteBuffer& data, int num_channels, int bits_per_sample, int source_rate);
    static NonnullRefPtr<ABuffer> create_with_samples(Vector<ASample>&& samples)
    {
        return adopt(*new ABuffer(move(samples)));
    }
    static NonnullRefPtr<ABuffer> create_with_shared_buffer(NonnullRefPtr<SharedBuffer>&& buffer)
    {
        return adopt(*new ABuffer(move(buffer)));
    }

    const ASample* samples() const { return (const ASample*)data(); }
    int sample_count() const { return m_buffer->size() / (int)sizeof(ASample); }
    const void* data() const { return m_buffer->data(); }
    int size_in_bytes() const { return m_buffer->size(); }
    int shared_buffer_id() const { return m_buffer->shared_buffer_id(); }
    SharedBuffer& shared_buffer() { return *m_buffer; }

private:
    explicit ABuffer(Vector<ASample>&& samples)
        : m_buffer(*SharedBuffer::create_with_size(samples.size() * sizeof(ASample)))
    {
        memcpy(m_buffer->data(), samples.data(), samples.size() * sizeof(ASample));
    }

    explicit ABuffer(NonnullRefPtr<SharedBuffer>&& buffer)
        : m_buffer(move(buffer))
    {
    }

    NonnullRefPtr<SharedBuffer> m_buffer;
    int m_sample_count { 0 };
};