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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#include "mcvmath.hxx"
// die folgenden Tabellen enthalten sin(phi) * 2**14
// fuer phi= 360Grad*2**-32 bis 360 Grad
// def. fuer x: phi=360Grad * 2**(x-16)
// d.h. x = 16 -> 360 Grad
// x = -16 -> (2**-16) * 360 Grad
// x: -16 ... 0 ... 15
//x= 0, 1, 2, 3, 4, 5, 6, 7,
// 8, 9, 10, 11, 12, 13, 14, 15
static const short CosTab[16] =
{
16384, 16384, 16384, 16384, 16384, 16384, 16384, 16383,
16379, 16364, 16305, 16069, 15137, 11585, 0, -16383
};
static const short SinTab[16]=
{
2, 3, 6, 13, 25, 50, 101, 201,
402, 804, 1606, 3196, 6270, 11585, 16384, 0
};
/**************************************************************************
|*
|* ImpMultBig2()
|*
|* Description Multiplier for FixPoint-calculations
|*
**************************************************************************/
// first parameter should be the larger one
Fix ImpMultBig2( const Fix& a, const Fix& b )
{
Fix f;
f.x = (((b.x+FIX_A2)>>FIX_P2)*a.x+FIX_A3)>>FIX_P3;
return f;
}
/**************************************************************************
|*
|* ImpSqrt()
|*
|* Description SquareRoot function for FixPoint-calculations
|*
**************************************************************************/
sal_uInt16 ImpSqrt( sal_uLong nRadi )
{
sal_uLong inf = 1;
sal_uLong sup = nRadi;
sal_uLong sqr;
if ( !nRadi )
return 0;
while ( (inf<<1) <= sup )
{
sup >>= 1;
inf <<= 1;
}
sqr = (sup+inf) >> 1; // startvalue for iteration
sqr = (nRadi/sqr + sqr) >> 1; // 2 Newton-Iterations suffice for
sqr = (nRadi/sqr + sqr) >> 1; // +- 1 Digit
return sal::static_int_cast< sal_uInt16 >(sqr);
}
/**************************************************************************
|*
|* ImpExPI()
|*
|* Description EXPI funktion or FixPoint-calculations
|*
**************************************************************************/
// e**(i*nPhi), unit nPhi: 2**16 == 360 degrees
FixCpx ImpExPI( sal_uInt16 nPhi )
{
short i;
FixCpx aIter(1L); // e**(0*i)
FixCpx Mul;
const char Sft=14-FIX_POST;
for ( i = 15; i >= 0; i-- )
{
if ( (1L<<i) & nPhi )
{
Mul.r.x = CosTab[i]>>Sft; // e**(i(phi1+phi2)) =
Mul.i.x = SinTab[i]>>Sft; // e**(i*phi1)) * e**(i*phi2))
aIter *= Mul;
}
}
return aIter;
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|
