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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /*
3 : * This file is part of the LibreOffice project.
4 : *
5 : * This Source Code Form is subject to the terms of the Mozilla Public
6 : * License, v. 2.0. If a copy of the MPL was not distributed with this
7 : * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 : *
9 : * This file incorporates work covered by the following license notice:
10 : *
11 : * Licensed to the Apache Software Foundation (ASF) under one or more
12 : * contributor license agreements. See the NOTICE file distributed
13 : * with this work for additional information regarding copyright
14 : * ownership. The ASF licenses this file to you under the Apache
15 : * License, Version 2.0 (the "License"); you may not use this file
16 : * except in compliance with the License. You may obtain a copy of
17 : * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18 : */
19 :
20 :
21 : #include "mcvmath.hxx"
22 :
23 :
24 : // die folgenden Tabellen enthalten sin(phi) * 2**14
25 : // fuer phi= 360Grad*2**-32 bis 360 Grad
26 : // def. fuer x: phi=360Grad * 2**(x-16)
27 : // d.h. x = 16 -> 360 Grad
28 : // x = -16 -> (2**-16) * 360 Grad
29 : // x: -16 ... 0 ... 15
30 : //x= 0, 1, 2, 3, 4, 5, 6, 7,
31 : // 8, 9, 10, 11, 12, 13, 14, 15
32 :
33 : static const short CosTab[16] =
34 : {
35 : 16384, 16384, 16384, 16384, 16384, 16384, 16384, 16383,
36 : 16379, 16364, 16305, 16069, 15137, 11585, 0, -16383
37 : };
38 : static const short SinTab[16]=
39 : {
40 : 2, 3, 6, 13, 25, 50, 101, 201,
41 : 402, 804, 1606, 3196, 6270, 11585, 16384, 0
42 : };
43 :
44 : /**************************************************************************
45 : |*
46 : |* ImpMultBig2()
47 : |*
48 : |* Description Multiplier for FixPoint-calculations
49 : |*
50 : **************************************************************************/
51 :
52 : // first parameter should be the larger one
53 :
54 0 : Fix ImpMultBig2( const Fix& a, const Fix& b )
55 : {
56 0 : Fix f;
57 0 : f.x = (((b.x+FIX_A2)>>FIX_P2)*a.x+FIX_A3)>>FIX_P3;
58 0 : return f;
59 : }
60 :
61 : /**************************************************************************
62 : |*
63 : |* ImpSqrt()
64 : |*
65 : |* Description SquareRoot function for FixPoint-calculations
66 : |*
67 : **************************************************************************/
68 :
69 0 : sal_uInt16 ImpSqrt( sal_uLong nRadi )
70 : {
71 0 : sal_uLong inf = 1;
72 0 : sal_uLong sup = nRadi;
73 : sal_uLong sqr;
74 :
75 0 : if ( !nRadi )
76 0 : return 0;
77 :
78 0 : while ( (inf<<1) <= sup )
79 : {
80 0 : sup >>= 1;
81 0 : inf <<= 1;
82 : }
83 0 : sqr = (sup+inf) >> 1; // startvalue for iteration
84 :
85 0 : sqr = (nRadi/sqr + sqr) >> 1; // 2 Newton-Iterations suffice for
86 0 : sqr = (nRadi/sqr + sqr) >> 1; // +- 1 Digit
87 :
88 0 : return sal::static_int_cast< sal_uInt16 >(sqr);
89 : }
90 :
91 : /**************************************************************************
92 : |*
93 : |* ImpExPI()
94 : |*
95 : |* Description EXPI funktion or FixPoint-calculations
96 : |*
97 : **************************************************************************/
98 :
99 : // e**(i*nPhi), unit nPhi: 2**16 == 360 degrees
100 :
101 0 : FixCpx ImpExPI( sal_uInt16 nPhi )
102 : {
103 : short i;
104 0 : FixCpx aIter(1L); // e**(0*i)
105 0 : FixCpx Mul;
106 0 : const char Sft=14-FIX_POST;
107 :
108 0 : for ( i = 15; i >= 0; i-- )
109 : {
110 0 : if ( (1L<<i) & nPhi )
111 : {
112 0 : Mul.r.x = CosTab[i]>>Sft; // e**(i(phi1+phi2)) =
113 0 : Mul.i.x = SinTab[i]>>Sft; // e**(i*phi1)) * e**(i*phi2))
114 0 : aIter *= Mul;
115 : }
116 : }
117 :
118 0 : return aIter;
119 : }
120 :
121 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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