/*
	SuperCollider real time audio synthesis system
    Copyright (c) 2002 James McCartney. All rights reserved.
	http://www.audiosynth.com

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
*/

#ifndef _SndBuf_
#define _SndBuf_

#include <stdint.h>

typedef struct SNDFILE_tag SNDFILE;

#ifdef SUPERNOVA

#include <atomic>
#include <cassert>

#ifdef __SSE2__
#include <emmintrin.h>
#endif


class rw_spinlock
{
	static const uint32_t unlocked_state = 0;
	static const uint32_t locked_state   = 0x80000000;
	static const uint32_t reader_mask    = 0x7fffffff;

#ifdef __SSE2__
	static inline void pause() { _mm_pause(); }
#else
	static inline void pause() { }
#endif

public:
	struct unique_lock
	{
		explicit unique_lock(rw_spinlock & sl) : sl_(sl) { sl_.lock();   }
		~unique_lock()                                   { sl_.unlock(); }

	private:
		rw_spinlock & sl_;
	};

	typedef unique_lock unique_lock;

	struct shared_lock
	{
		explicit shared_lock(rw_spinlock & sl): sl_(sl) { sl_.lock_shared();   }
		~shared_lock()                                  { sl_.unlock_shared(); }

	private:
		rw_spinlock & sl_;
	};

	rw_spinlock()                                    = default;
	rw_spinlock(rw_spinlock const & rhs)             = delete;
	rw_spinlock & operator=(rw_spinlock const & rhs) = delete;
	rw_spinlock(rw_spinlock && rhs)                  = delete;
	rw_spinlock & operator=(rw_spinlock & rhs)       = delete;

	~rw_spinlock() { assert(state == unlocked_state); }

	void lock()
	{
		for (;;) {
			while( state.load(std::memory_order_relaxed) != unlocked_state )
				pause();

			uint32_t expected = unlocked_state;
			if( state.compare_exchange_weak(expected, locked_state, std::memory_order_acquire) )
				break;
		}
	}

	bool try_lock()
	{
		uint32_t expected = unlocked_state;
		if( state.compare_exchange_strong(expected, locked_state, std::memory_order_acquire) )
			return true;
		else
			return false;
	}

	void unlock()
	{
		assert( state.load(std::memory_order_relaxed) == locked_state) ;
		state.store( unlocked_state, std::memory_order_release );
	}

	void lock_shared()
	{
		for(;;) {
			/* with the mask, the cas will fail, locked exclusively */
			uint32_t current_state    = state.load( std::memory_order_acquire ) & reader_mask;
			const uint32_t next_state = current_state + 1;

			if( state.compare_exchange_weak(current_state, next_state, std::memory_order_acquire) )
				break;
			pause();
		}
	}

	bool try_lock_shared()
	{
		/* with the mask, the cas will fail, locked exclusively */
		uint32_t current_state    = state.load(std::memory_order_acquire) & reader_mask;
		const uint32_t next_state = current_state + 1;

		if( state.compare_exchange_strong(current_state, next_state, std::memory_order_acquire) )
			return true;
		else
			return false;
	}

	void unlock_shared()
	{
		for(;;) {
			uint32_t current_state    = state.load(std::memory_order_relaxed); /* we don't need the reader_mask */
			const uint32_t next_state = current_state - 1;

			if( state.compare_exchange_weak(current_state, uint32_t(next_state)) )
				break;
			pause();
		}
	}

private:
	std::atomic<uint32_t> state {unlocked_state};
};

#endif

struct SndBuf
{
	double samplerate;
	double sampledur; // = 1/ samplerate
	float *data;
	int channels;
	int samples;
	int frames;
	int mask;	// for delay lines
	int mask1;	// for interpolating oscillators.
	int coord;	// used by fft ugens
	SNDFILE *sndfile; // used by disk i/o
	// SF_INFO fileinfo; // used by disk i/o
#ifdef SUPERNOVA
	bool isLocal;
	mutable rw_spinlock lock;
#endif
};

typedef struct SndBuf SndBuf;

struct SndBufUpdates
{
	int reads;
	int writes;
};
typedef struct SndBufUpdates SndBufUpdates;

enum { coord_None, coord_Complex, coord_Polar };

inline float PhaseFrac(uint32_t inPhase)
{
	union { uint32_t itemp; float ftemp; } u;
	u.itemp = 0x3F800000 | (0x007FFF80 & ((inPhase)<<7));
	return u.ftemp - 1.f;
}

inline float PhaseFrac1(uint32_t inPhase)
{
	union { uint32_t itemp; float ftemp; } u;
	u.itemp = 0x3F800000 | (0x007FFF80 & ((inPhase)<<7));
	return u.ftemp;
}

inline float lookup(const float *table, int32_t phase, int32_t mask)
{
	return table[(phase >> 16) & mask];
}


#define xlobits 14
#define xlobits1 13

inline float lookupi(const float *table, uint32_t phase, uint32_t mask)
{
	float frac = PhaseFrac(phase);
	const float *tbl = table + ((phase >> 16) & mask);
	float a = tbl[0];
	float b = tbl[1];
	return a + frac * (b - a);
}

inline float lookupi2(const float *table, uint32_t phase, uint32_t mask)
{
	float frac = PhaseFrac1(phase);
	const float *tbl = table + ((phase >> 16) & mask);
	float a = tbl[0];
	float b = tbl[1];
	return a + frac * b;
}

inline float lookupi1(const float* table0, const float* table1, uint32_t pphase, int32_t lomask)
{
	float pfrac = PhaseFrac1(pphase);
	uint32_t index = ((pphase >> xlobits1) & lomask);
	float val1 = *(const float*)((const char*)table0 + index);
	float val2 = *(const float*)((const char*)table1 + index);
	return val1 + val2 * pfrac;
}


inline float lininterp(float x, float a, float b)
{
	return a + x * (b - a);
}

inline float cubicinterp(float x, float y0, float y1, float y2, float y3)
{
	// 4-point, 3rd-order Hermite (x-form)
	float c0 = y1;
	float c1 = 0.5f * (y2 - y0);
	float c2 = y0 - 2.5f * y1 + 2.f * y2 - 0.5f * y3;
	float c3 = 0.5f * (y3 - y0) + 1.5f * (y1 - y2);

	return ((c3 * x + c2) * x + c1) * x + c0;
}


#endif
