OpenShot Audio Library | OpenShotAudio 1.0.0
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juce_LagrangeInterpolator.cpp
1/*
2 ==============================================================================
3
4 This file is part of the JUCE library.
5 Copyright (c) 2022 - Raw Material Software Limited
6
7 JUCE is an open source library subject to commercial or open-source
8 licensing.
9
10 The code included in this file is provided under the terms of the ISC license
11 http://www.isc.org/downloads/software-support-policy/isc-license. Permission
12 To use, copy, modify, and/or distribute this software for any purpose with or
13 without fee is hereby granted provided that the above copyright notice and
14 this permission notice appear in all copies.
15
16 JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
17 EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
18 DISCLAIMED.
19
20 ==============================================================================
21*/
22
23namespace juce
24{
25
26template <int k>
27struct LagrangeResampleHelper
28{
29 static forcedinline void calc (float& a, float b) noexcept { a *= b * (1.0f / k); }
30};
31
32template <>
33struct LagrangeResampleHelper<0>
34{
35 static forcedinline void calc (float&, float) noexcept {}
36};
37
38template <int k>
39static float calcCoefficient (float input, float offset) noexcept
40{
41 LagrangeResampleHelper<0 - k>::calc (input, -2.0f - offset);
42 LagrangeResampleHelper<1 - k>::calc (input, -1.0f - offset);
43 LagrangeResampleHelper<2 - k>::calc (input, 0.0f - offset);
44 LagrangeResampleHelper<3 - k>::calc (input, 1.0f - offset);
45 LagrangeResampleHelper<4 - k>::calc (input, 2.0f - offset);
46 return input;
47}
48
49float Interpolators::LagrangeTraits::valueAtOffset (const float* inputs, float offset, int index) noexcept
50{
51 float result = 0.0f;
52
53 result += calcCoefficient<0> (inputs[index], offset); if (++index == 5) index = 0;
54 result += calcCoefficient<1> (inputs[index], offset); if (++index == 5) index = 0;
55 result += calcCoefficient<2> (inputs[index], offset); if (++index == 5) index = 0;
56 result += calcCoefficient<3> (inputs[index], offset); if (++index == 5) index = 0;
57 result += calcCoefficient<4> (inputs[index], offset);
58
59 return result;
60}
61
62} // namespace juce