///////////////////////////////////////////////////////////////////////////////
/// -*- coding: UTF-8 -*-
///
/// \file   Discovery/Inc/Utils.h
/// \brief	Various Utilities...
/// \author Heinrichs Weikamp
/// \date   2018
///
/// $Id$
///////////////////////////////////////////////////////////////////////////////
/// \par Copyright (c) 2014-2018 Heinrichs Weikamp gmbh
///
///     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 3 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, see <http://www.gnu.org/licenses/>.
//////////////////////////////////////////////////////////////////////////////

#ifndef UTILS_H
#define UTILS_H

#include <stdint.h>
#include <stdbool.h>
#include <math.h>

#ifdef FloatToFixed
#undef FloatToFixed
#undef IntToFixed
#undef FixedToFloat
#undef FixedToInt
#endif

//
// 20.12 fixed-point operations
//

#define Fix(val) ((val)*4096)
#define F(val) Fix(val)

#define FixSqrt2 5793
#define FixInvSqrt2 2896
#define FixSinPiDiv4 FixInvSqrt2
#define FixCosPiDiv4 FixInvSqrt2
#define FixSinPiDiv8 1567
#define FixCosPiDiv8 3784

static inline int32_t FloatToFixed(float val) { return val*4096.0f; }
static inline int32_t IntToFixed(int val) { return val<<12; }
static inline int32_t IntToFixedPlusHalf(int val) { return (val<<12)+0x800; }

static inline float FixedToFloat(int32_t val) { return (float)val/4096.0f; }
static inline int32_t FixedToInt(int32_t val) { return val>>12; }
static inline int32_t FixedToRoundedInt(int32_t val) { return (val+0x800)>>12; }

//static inline int32_t FixedMul(int32_t a,int32_t b) { return ((int64_t)a*(int64_t)b)>>16; }

static inline int32_t imin(int32_t a,int32_t b) { return a<b?a:b; }
static inline int32_t imax(int32_t a,int32_t b) { return a>b?a:b; }
static inline int32_t iabs(int32_t a) { return a<0?-a:a; }
static inline int32_t isign(int32_t a) { return a>0?1:a<0?-1:0; }

static inline int64_t imul64(int64_t a, int64_t b) { return (a*b)>>12; }
static inline int32_t imul(int32_t a, int32_t b) { return (int32_t)imul64(a,b); }

static inline int64_t idiv64(int64_t num,int64_t den) { return (num<<12)/den; }
static inline int32_t idiv(int32_t num,int32_t den) { return (int32_t)idiv64(num,den); }

static inline int64_t isq64(int64_t val) { return imul64(val,val); }
static inline int32_t isq(int32_t val) { return imul(val,val); }

static uint32_t sqrti(uint32_t n)
{
	uint32_t s,t;

	#define sqrtBit(k) \
	t = s+(1UL<<(k-1)); t <<= k+1; if (n >= t) { n -= t; s |= 1UL<<k; }

	s=0;
	if(n>=1<<30) { n-=1<<30; s=1<<15; }
	sqrtBit(14); sqrtBit(13); sqrtBit(12); sqrtBit(11); sqrtBit(10);
	sqrtBit(9); sqrtBit(8); sqrtBit(7); sqrtBit(6); sqrtBit(5);
	sqrtBit(4); sqrtBit(3); sqrtBit(2); sqrtBit(1);
	if(n>s<<1) s|=1;

	#undef sqrtBit

	return s;
}

static inline int64_t isqrt64(int64_t val) { return sqrti((uint64_t)val<<12); }
static inline int32_t isqrt(int32_t val) { return sqrti((uint64_t)val<<12); }

static inline int64_t inorm64(int64_t a,int64_t b) { return sqrt((double)a*(double)a+(double)b*(double)b); }
static inline int32_t inorm(int32_t a,int32_t b) { return sqrt((double)a*(double)a+(double)b*(double)b); }

static inline int32_t ifloor(int a) { return a&~0xfff; }
static inline int32_t ifrac(int a) { return a&0xfff; }

int32_t isin(int a);
static inline int32_t icos(int a) { return isin(a+1024); }
static inline int32_t itan(int a) { return idiv(isin(a),icos(a)); } // TODO: use a table
static inline int32_t idegrees(int degrees) { return degrees*4096.0f/360.0f; }
static inline int32_t iradians(float radians) { return radians*4096.0f/2/3.1415926535897932f; }

static inline int32_t ilerp(int32_t a,int32_t b,int32_t t)
{
	return a+imul(b-a,t);
}

/*static inline int32_t islerp(int32_t a,int32_t b,int32_t t)
{
	return a;
}*/

//
// Bitwise operations
//

static inline int CountBits32(uint32_t val)
{
	val=(val&0x55555555)+((val&0xaaaaaaaa)>>1);
	val=(val&0x33333333)+((val&0xcccccccc)>>2);
	val=(val&0x0f0f0f0f)+((val&0xf0f0f0f0)>>4);
	val=(val&0x00ff00ff)+((val&0xff00ff00)>>8);
	val=(val&0x0000ffff)+((val&0xffff0000)>>16);
	return val;
}

static inline int CountBits16(uint16_t val)
{
	val=(val&0x5555)+((val&0xaaaa)>>1);
	val=(val&0x3333)+((val&0xcccc)>>2);
	val=(val&0x0f0f)+((val&0xf0f0)>>4);
	val=(val&0x00ff)+((val&0xff00)>>8);
	return val;
}

static inline int CountBits8(uint8_t val)
{
	val=(val&0x55)+((val&0xaa)>>1);
	val=(val&0x33)+((val&0xcc)>>2);
	val=(val&0x0f)+((val&0xf0)>>4);
	return val;
}

static inline uint32_t ReverseBits32(uint32_t val)
{
	val=((val>>1)&0x55555555)|((val<<1)&0xaaaaaaaa);
	val=((val>>2)&0x33333333)|((val<<2)&0xcccccccc);
	val=((val>>4)&0x0f0f0f0f)|((val<<4)&0xf0f0f0f0);
	val=((val>>8)&0x00ff00ff)|((val<<8)&0xff00ff00);
	val=((val>>16)&0x0000ffff)|((val<<16)&0xffff0000);
	return val;
}

static inline uint16_t ReverseBits16(uint16_t val)
{
	val=((val>>1)&0x5555)|((val<<1)&0xaaaa);
	val=((val>>2)&0x3333)|((val<<2)&0xcccc);
	val=((val>>4)&0x0f0f)|((val<<4)&0xf0f0);
	val=((val>>8)&0x00ff)|((val<<8)&0xff00);
	return val;
}

static inline uint8_t ReverseBits8(uint8_t val)
{
	val=((val>>1)&0x55)|((val<<1)&0xaa);
	val=((val>>2)&0x33)|((val<<2)&0xcc);
	val=((val>>4)&0x0f)|((val<<4)&0xf0);
	return val;
}

static int LowestBitSet32(uint32_t val)
{
	if(val==0) return -1;
	return CountBits32(val^val-1)-1;
}

static int LowestBitSet16(uint16_t val)
{
	if(val==0) return -1;
	return CountBits16(val^val-1)-1;
}

static int LowestBitSet8(uint8_t val)
{
	if(val==0) return -1;
	return CountBits8(val^val-1)-1;
}

#endif // UTILS_H