// Heavily based on:

//

// Band-limited sound synthesis and buffering

// Blip_Buffer 0.4.0

// http://www.slack.net/~ant/

#ifndef BLIPBUFFER_HH

#define BLIPBUFFER_HH

#include "FixedPoint.hh"

#include <array>

namespace openmsx {

class BlipBuffer

{

public:

	// Number of bits in phase offset. Fewer than 6 bits (64 phase offsets) results

	// in noticeable broadband noise when synthesizing high frequency square waves.

	static constexpr int BLIP_PHASE_BITS = 10;

	using TimeIndex = FixedPoint<BLIP_PHASE_BITS>;

	BlipBuffer();

	// Update amplitude of waveform at given time. Time is in output sample

	// units and since the last time readSamples() was called.

	void addDelta(TimeIndex time, float delta);

	// Read the given amount of samples into destination buffer.

	template<size_t PITCH>

	bool readSamples(float* out, size_t samples);

private:

	template<size_t PITCH>

	void readSamplesHelper(float* out, size_t samples);

private:

	static constexpr size_t BUFFER_SIZE = 1 << 14;

	static constexpr size_t BUFFER_MASK = BUFFER_SIZE - 1;

	std::array<float, BUFFER_SIZE> buffer;

	size_t offset = 0;

	ptrdiff_t availSamp = 0;

	float accum = 0.0f;

};

} // namespace openmsx

#endif