113 lines
4.0 KiB
C++
113 lines
4.0 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2017 - ROLI Ltd.
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JUCE is an open source library subject to commercial or open-source
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licensing.
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The code included in this file is provided under the terms of the ISC license
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http://www.isc.org/downloads/software-support-policy/isc-license. Permission
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To use, copy, modify, and/or distribute this software for any purpose with or
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without fee is hereby granted provided that the above copyright notice and
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this permission notice appear in all copies.
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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//==============================================================================
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/**
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This class contains some helpful static methods for dealing with decibel values.
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@tags{Audio}
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*/
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class Decibels
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{
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public:
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//==============================================================================
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/** Converts a dBFS value to its equivalent gain level.
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A gain of 1.0 = 0 dB, and lower gains map onto negative decibel values. Any
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decibel value lower than minusInfinityDb will return a gain of 0.
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*/
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template <typename Type>
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static Type decibelsToGain (Type decibels,
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Type minusInfinityDb = Type (defaultMinusInfinitydB))
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{
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return decibels > minusInfinityDb ? std::pow (Type (10.0), decibels * Type (0.05))
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: Type();
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}
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/** Converts a gain level into a dBFS value.
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A gain of 1.0 = 0 dB, and lower gains map onto negative decibel values.
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If the gain is 0 (or negative), then the method will return the value
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provided as minusInfinityDb.
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*/
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template <typename Type>
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static Type gainToDecibels (Type gain,
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Type minusInfinityDb = Type (defaultMinusInfinitydB))
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{
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return gain > Type() ? jmax (minusInfinityDb, static_cast<Type> (std::log10 (gain)) * Type (20.0))
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: minusInfinityDb;
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}
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//==============================================================================
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/** Converts a decibel reading to a string.
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By default the returned string will have the 'dB' suffix added, but this can be removed by
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setting the shouldIncludeSuffix argument to false. If a customMinusInfinityString argument
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is provided this will be returned if the value is lower than minusInfinityDb, otherwise
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the return value will be "-INF".
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*/
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template <typename Type>
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static String toString (Type decibels,
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int decimalPlaces = 2,
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Type minusInfinityDb = Type (defaultMinusInfinitydB),
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bool shouldIncludeSuffix = true,
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StringRef customMinusInfinityString = {})
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{
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String s;
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s.preallocateBytes (20);
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if (decibels <= minusInfinityDb)
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{
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if (customMinusInfinityString.isEmpty())
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s << "-INF";
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else
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s << customMinusInfinityString;
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}
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else
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{
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if (decibels >= Type())
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s << '+';
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if (decimalPlaces <= 0)
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s << roundToInt (decibels);
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else
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s << String (decibels, decimalPlaces);
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}
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if (shouldIncludeSuffix)
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s << " dB";
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return s;
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}
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private:
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//==============================================================================
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enum { defaultMinusInfinitydB = -100 };
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Decibels() = delete; // This class can't be instantiated, it's just a holder for static methods..
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};
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} // namespace juce
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